The detailed furnace has also been applied, by Mr. Hoyt, to the combination of bituminous coal,A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling through.A diagram showing a wet-tim furnace with multiple compartments and small air-spaces for preventing coal dust from falling though  BOILERS, STEAM. 175 Steam is used to produce the heat, consisting of a steam-pipe with a discharge office about one-tenth of an inch in diameter, discharging into the blast-pipe, which is open to the air at the outer end. Automatic arrangements for supplying coal to furnaces are sometimes employed. Smith's Auto- matic Boiler is described in Fig. 408. This is a supply-pump, from which falls into a revolving crusier, and in breaks up the coal, which is then conveyed by a belt to the boiler. Stokers are usually constructed of cast-iron, and should have openings in their sides sufficient to admit of the passage of the air necessary for combustion above the fire. The stokers are usually provided with a door, through which the air can enter, and also with a blast-pipe, through which the air circulates, are sometimes employed, and grate-stokers have been used in England. In burning coal, it is usually found desirable that the air shall be admitted directly into the furnace-door, and sometimes, for the purpose of effecting more thorough mixture, the air is blown through a tube connected with the furnace-door. In some cases, this tube is connected with a blast-pipe, so that after a fresh supply of coal is put into the furnace, the air may be admitted through this tube when the coal is ignited. In the "Sixth Annual Report of the Cincinnati Exposition," there are descriptions of several stokers, and accounts of experiments made with them. For water-heating purposes, in which no combustion occurs, after leaving the boiler, escape directly into the chimney, they must pass off at the temperature of the steam in the boiler, at least. By causing the steam to expand in passing through a pipe or nozzle, its velocity will increase, and consequently its heat will be communicated to the atmosphere. As long as this process continues, it will continue until all the heat has been communicated to the atmosphere. The heater may either be open, as when the exhaust steam is direct con- nected with the feed-water, or the water may be forced through a pipe or nozzle into the atmosphere. When using hot water for heating purposes, the feed-water must be drawn from the heater by the pump, which must thus force hot water, while with the latter cold water can be supplied by means of a separate pump. Some forms of heaters are intended to purify the water as well as to heat it by the use of a series of driven pumps or basins, in which the solid material will be deposited and removed before it reaches the heater. All natural waters hold very little oxygen; but when heated sufficiently, even in the latter state, they are capable of being purified by filtration on a scale sufficiently large to supply a moderate-sized steam-engine at a light expense, has yet come into practical use. How- A diagram showing a steam engine with various parts labeled. 408 A diagram showing a steam engine with various parts labeled. 409 A diagram showing a steam engine with various parts labeled. 410 A diagram showing a steam engine with various parts labeled. 411  176 BOILERS, STEAM. ever, it occurred to an inventor several years ago to hit upon a very simple and effectual substitute. And that was, instead of separating the water from the dirt, before passing it into the boiler, to sepa- rate and collect the dirt from the water, after it is in the boiler, by means of a series of vessels, either of glass or metal, placed in the boiler, and communicating with each other by pipes, so that what collectively might be considered a substitute for a false bottom, upon or into which all the matters held in suspension in the water might be deposited, would be removed from the water when it was boiled. The inventor thought this idea so good that he patented it, but he never lived long enough to know that they were even meant for imitation. These sediment vessels operate much after the same manner as certain quiet or still places do along the banks of rivers and streams. In these places, where the current is slow, and where no great force of water strikes against the sides of the banks, the mud and sand being deposited on the bottom of such shores, while any movable matter being accidentally deposited, they remain free from adhesion and not clinging to one another. But in a river or stream where the current is strong and rapid, and where it pre- vails, the steam rising from the boiler-bottom—the sole cause of cillation in all cases—being the agitating agent of all the particles of water suspended in the water, and causing them to move about, however violently it may boil externally; and the more violently the water boils, the more rapidly the internal vessel collects all loose sediment floating in the water. Hence, excepting those places in rivers and streams where there is a very slow current, keeping a boiler clean. The only difficulty in its practical application was liability to neglect in cleaning out the collectors themselves when they got filled up with sediment. This difficulty has been overcome by Mr. A. B. Armstrong. For the above reason it appears desirable to the patentee to have his cleansing apparatus made so effective as to prevent any deposit from being formed in his boilers at all times. For this purpose he is putting down the steam; which improvement A. B. Armstrong effected in 1898, when he first complete boiler- cleaning apparatus was applied and used on steamships belonging to Messrs. William H. Hanna Marshall & Son, Ltd., and also on steamships belonging to Messrs. J. W. Allen & Co., Ltd. Since the above period they have continued in general use in Lancashire. The principle of this invention is shown in Fig. 411. Many hundreds have been made and adapted to various kinds of boilers, including those of railway locomotives and steamships. In the heating apparatus of a locomotive engine, for example, it is generally necessary to have a gener- ally speaking, unnecessary, except for the purpose of preventing priming, which they must sufficiently or when they are not sufficient to prevent priming from occurring. The apparatus consists essentially of a pipe made with the narrow collecting aperture adjusted partly above and partly below the surface of the water. In this way it is used by opening the valve at the end of the boiler, and putting the handle of the pump on top of the boiler. The water is drawn through this pipe into a receiver placed at some distance from the outlet of the boiler are discharged upward through the pipe on the right hand. This operation creates a current, A diagram showing a steam boiler with a device for cleaning out sediment. Longitudinal section showing arrangement of Collectors. which draws all the water from both tanks; and then by opening from all parts of the water surface into the collector vessel and down into the receiver, whence they are discharged to the outside of the boiler by a repetition of the process. By thus drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all water from both tanks at once, and by drawing off all水  BOILERS, STEAM. 177 one of the water to prevent it from becoming too highly aerated. Blowing off is sometimes per- formed at intervals from the bottom of the boiler, but the better practice is to maintain a continuous low-off near the upper surface of the water in the boiler. A double feed-cock is shown in Fig. 413. The lower mouth of the blow-off pipe within the boiler is dis- closed near the water-level, whereby it catches and removes from the boiler the particles of impal- lable matter which may have been carried into it by the steam. E. Lamb attaches a valve to the mouth of the blow-off pipe, regulated by a float, with the view of preventing any loss of water due to evaporation. The float is made of copper, of the form of an oblate spheroid, with a tube passing through it for the reception of a spindle, the position of which is regulated by a screw-rod. The spindle is connected with a lever, which is attached to a screw-rod cut upon the spindle. The valve resembles a flue-key. The lower end of the spindle is connected with a ball-valve, which is placed in a groove cut in the side of the cylinder. When the spindle moves in a guide attached to any convenient part of the boiler. By this apparatus the loss of water due to evaporation is prevented, and at the same time, when necessary, a certain quan- tity of water blown off is either decidedly great or insufficient, the position of the feed-cock is altered so as to give a diminished or increased supply. When more fuel-water is admitted, the float will rise higher up in its tube, and consequently less water will be blown off ; when less fuel-water is admitted, the contrary effect is produced. The quantity of water blown off can be regulated by altering the position of the feed-cock, so that all the water within the boiler at a uniform density so soon as the right position of the feed-cock is ascer- tained. In order to avoid any accidental interruption of blowing off, two or more blow-offs are applied, and an efficient safety-gauge is indispensable, as there can otherwise be no limitation of the accidental interruption of the operation, and much mischief may be the result. In the ordi- nary way of blowing off, where the engineer keeps the blow-off cocks open until the water-level has descended any given number of inches, it is certain that, if the water-level descends, a certain volume of water will be blown off. This volume will depend on several causes; one cause being a differ- ence of pressure in the different boilers, one boiler having discharged its contents into another and leaving behind it some quantity of water. Another cause being that some quantity of water may be left in one boiler at a time, a determinable quantity of water is expelled by blowing out at definite intervals with a certainty which has been found to be very satisfactory. DAB VEL DAB VEL The following table shows how much use the use of the safety-gauge is in cases where boilers fitted with any description of continuous heating are used. Covering Boilers.—Internally fired boilers, by which term I mean those in which all parts of combustion are only in contact with boiler-heating surfaces are generally covered with metal plates, or with sheets of sheet iron or sheet steel. These plates are kept hot by radiation from below, or by fettling, plas- ter, straw, or some other material that is not a good con- ductor of heat. In such boilers it is necessary to keep the covering hot throughout its whole length and height, of the covering, in the case of a small boiler in an open shot-blast furnace (Fig. 414), and also in many cases for boilers and steam-pipes. The Chalmers-Spencer covering, Fig. 415, consists of two layers of cloth separated by a layer of felt or felted cotton wool; these layers are held together by means separated by means of wire cloth, so as to form an air- space, and the arrangement of H. W. John's covering, Fig. 416. In order to ascertain whether this covering was effective, experiments, by J. C. Handley, on the economic effect of such coverings were made on locomotives belonging to the locomotive type, was published in the Journal of the Franklin Institute, April, 1877. The following is a summary of the results obtained : 18  # BOILERS, STEAM. **Economic Effect of applying the Chalmers-Burnes Covering.**

	PERIMETER OF STEAM, IN FEET PER SQUARE INCH, ABOVE 100 lbs. per sq. inch.			PERIMETER OF STEAM, IN FEET PER SQUARE INCH, ABOVE 150 lbs. per sq. inch.			PERIMETER OF STEAM, IN FEET PER SQUARE INCH, ABOVE 200 lbs. per sq. inch.			PERIMETER OF STEAM, IN FEET PER SQUARE INCH, ABOVE 250 lbs. per sq. inch.
	100	150	200	100	150	200	100	150	200	100	150	200
Ratio of steam raised : Boiler uncoated.	18.7	18.6	18.5	17.9	17.8	17.7	17.3	17.2	17.1	16.9	16.8	16.7
To steam raised by boiler uncoated : to boiler uncoated.
Ratio of steam raised : Boiler coated.	43.3

Some experiments were made by E. Burnes, in 1859, to determine the value of various materials for coating steam-pipes (see Journal of the Franklin Institute, March, 1879). A summary of his results is contained in the accompanying table:

SUMMARY OF EXPERIMENTS ON COATINGS FOR STEAM-PIPES.	KIND OF NON-CONDUCTING ORAYING EXPLORER.	Periods of Use at Various Pressures.		Thermal Conductivity,		Per Cent of Heat Lost by Conduction,		Per Cent of Heat Lost by Radiation,		Per Cent of Heat Lost by Convection,		Per Cent of Heat Lost by Evaporation,		Per Cent of Heat Lost by Other Causes.
		Average Time on Pipe.	Pounds of Steam Per Hour.	Average Time on Pipe.	Pounds of Steam Per Hour.	Average Time on Pipe.	Pounds of Steam Per Hour.	Average Time on Pipe.	Pounds of Steam Per Hour.	Average Time on Pipe.	Pounds of Steam Per Hour.	Average Time on Pipe.	Pounds of Steam Per Hour.	Average Time on Pipe.

SUMMARY OF EXPERIMENTS ON COATINGS FOR STEAM-PIPES.	KIND OF NON-CONDUCTING ORAYING EXPLORER.	Average Time on Pipe.	Pounds of Steam Per Hour.	Average Time on Pipe.	Pounds of Steam Per Hour.	Average Time on Pipe.	Pounds of Steam Per Hour.	Average Time on Pipe.	Pounds of Steam Per Hour.	Average Time on Pipe.	Pounds of Steam Per Hour.	Average Time on Pipe.	Pounds of Steam Per Hour.	Average Time on Pipe.

SUMMARY OF EXPERIMENTS ON COATINGS FOR STEAM-PIPES.	KIND OF NON-CONDUCTING ORAYING EXPLORER.	Average Time on Pipe.	Pounds of Steam Per Hour.	Average Time on Pipe.	Pounds of Steam Per Hour.	Average Time on Pipe.	Pounds of Steam Per Hour.	Average Time on Pipe.	Pounds of Steam Per Hour.	Average Time on Pipe.	Pounds of Steam Per Hour.	Average Time on Pipe. The time spent with constant steam, thickness of cover on copper pipe, in inches. The time spent with constant steam, thickness of cover on heavy metal and cheaper stove, around which steam is conducted through a tube or pipe, and the same time spent between the outer and the gallery pipe. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick. The time spent with constant steam, thick.

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Safety Valve.-A safety-valve is so named because it is designed to prevent undue pressure in the boiler or vessel in which it is placed. The pressure in any vessel is governed by the rate at which heat is supplied to it and the rate at which heat is removed from it; but this is not always uniform and may vary greatly according to circumstances. In the light of experience it may be well to consider questions that are constantly arising in the practice of all who have charge of steam-boilers; viz:

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Safety Valve.-A safety-valve is so named because it is designed to prevent undue pressure in the boiler or vessel in which it is placed. The pressure in any vessel is governed by the rate at which heat is supplied to it and the rate at which heat is removed from it; but this is not always uniform and may vary greatly according to circumstances. In the light of experience it may be well to consider questions that are constantly arising in the practice of all who have charge of steam-boilers; viz:

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Safety Valve.-A safety-valve is so named because it is designed to prevent undue pressure in the boiler or vessel in which it is placed. The pressure in any vessel is governed by the rate at which heat is supplied to it and the rate at which heat is removed from it; but this is not always uniform and may vary greatly according to circumstances. In the light of experience it may be well to consider questions that are constantly arising in the practice of all who have charge of steam-boilers; viz:

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Safety Valve.-A safety-valve is so named because it is designed to prevent undue pressure in the boiler or vessel in which it is placed. The pressure in any vessel is governed by the rate at which heat is supplied to it and the rate at which heat is removed from it; but this is not always uniform and may vary greatly according to circumstances. In the light of experience it may be well to consider questions that are constantly arising in the practice of all who have charge of steam-boilers; viz:

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Safety Valve.-A safety-valve is so named because it is designed to prevent undue pressure in the boiler or vessel in which it is placed. The pressure in any vessel is governed by the rate at which heat is supplied to it and the rate at which heat is removed from it; but this is not always uniform and may vary greatly according to circumstances. In the light of experience it may be well to consider questions that are constantly arising in the practice of all who have charge of steam-boilers; viz:

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Safety Valve.-A safety-valve is so named because it is designed to prevent undue pressure in the boiler or vessel in which it is placed. The pressure in any vessel is governed by the rate at which heat is supplied to it and the rate at which heat is removed from it; but this is not always uniform and may vary greatly according to circumstances. In the light of experience it may be well to consider questions that are constantly arising in the practice of all who have charge of steam-boilers; viz:

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Safety Valve.-A safety-valve is so named because it is designed to prevent undue pressure in the boiler or vessel in which it is placed. The pressure in any vessel is governed by the rate at which heat is supplied to it and the rate at which heat is removed from it; but this is not always uniform and may vary greatly according to circumstances. In the light of experience it may be well to consider questions that are constantly arising in the practice of all who have charge of steam-boilers; viz:

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Safety Valve.-A safety-valve is so named because it is designed to prevent undue pressure in the boiler or vessel in which it is placed. The pressure in any vessel is governed by the rate at which heat is supplied to it and the rate at which heat is removed from it; but this is not always uniform and may vary greatly according to circumstances. In the light of experience it may be well to consider questions that are constantly arising in the practice of all who have charge of steam-boilers; viz:

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Safety Valve.-A safety-valve is so named because it is designed to prevent undue pressure in the boiler or vessel in which it is placed. The pressure in any vessel is governed by the rate at which heat is supplied to it and the rate at which heat is removed from it; but this is not always uniform and may vary greatly according to circumstances. In the light of experience it may be well to consider questions that are constantly arising in the practice of all who have charge of steam-boilers; viz:

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Safety Valve.-A safety-valve is so named because it is designed to prevent undue pressure in the boiler or vessel in which it is placed. The pressure in any vessel is governed by the rate at which heat is supplied to it and the rate at which heat is removed from it; but this is not always uniform and may vary greatly according to circumstances. In the light of experience it may be well to consider questions that are constantly arising in the practice of all who have charge of steam-boilers; viz:

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Safety Valve.-A safety-valve is so named because it is designed to prevent undue pressure in the boiler or vessel in which it is placed. The pressure in any vessel is governed by the rate at which heat is supplied to it and the rate at which heat is removed from it; but this is not always uniform and may vary greatly according to circumstances. In the light of experience it may be well to consider questions that are constantly arising in the practice of all who have charge of steam-boilers; viz:

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Safety Valve.-A safety-valve is so named because it is designed to prevent undue pressure in the boiler or vessel in which it  BOILERS, STEAM. 179 Position of weight: $w = \frac{0.7854 \times D^2 \times S \times P - L \times I - V \times P}{W}$ Diameter to open at given steam-pressure: $D = \sqrt{\left(\frac{P + X + L + V + F \times P}{0.7854 \times S \times P}\right)}$ Area of opening for given lift: (a) For a lift less than depth of seat: $A = 3.1416 \times [D \times X \times \sin a + e^2 \times (d \times a)^2 \times \cos a]$ (b) For a lift greater than depth of seat: $A = 3.1416 \times [D \times X \times e + w^2 \times (d \times a)^2 \times \cos a + D \times (e - h)]$ Diameter for given lift: (a) For a lift less than depth of seat: $D = 3.1416 \times X^2 \times (\sin a) \times X^2 \times \cos a$ (b) For a lift greater than depth of seat: $D = 3.1416 \times X^2 \times (\sin a) \times X^2 \times \cos a$ The following table will be found useful in connection with the last two rules, and examples illustrating the application of the formulas are appended: J B° ANGLE. Size. Code. ANGLE. Size. Code. ANGLE. Size. Code. B° 30 J B° 30 J B° 30 J B° 30 J B° 30 J B° 30 J B° 30 J B° 30 J B° 30 J B° 30 J B° 30 J B° 30 J B° 30 J B° 30 J B° 30 J B° 30 J B° 30 J B° 30 30 J B° 30 J B° 30 J B° 30 J B° 30 J B° 30 J B° 30 J B° 30 J B° 30 J B° 30 J B° 30 J B° 30 J B° 30 J B° 30 J B° 30 J B° 30 J B° 30 J B° 30 J B° 30 J B° 30 J B° 30 J B° 30 J B° 30 J B° 30 J Example.—1. A given safety-valve has a weight of 5 lb. 54 inches from the fulcrum, the lever weighs 6 lb., and the centre of gravity is 18 inches from the fulcrum; the weight of the valve is 5 lb., and its centre is 4 inches from the fulcrum. The diameter of the valve is 2 inches. At what pressure will the valve open? $$\frac{5}{(54-4+18+5)} = 1.58$$ lbs. per square inch. 2. The ball of a safety-valve weighing 1 lb., the lever weighs 1 lb., the valve weighs 5 lb., and has a diameter of 9 inches. The distance of the centre of gravity of the lever from the fulcrum is 18 inches, and the distance of the centre of the valve from the fulcrum is 4 inches. How far from the fulcrum must the ball be placed so that when the valve lifts one as a pressure of 100 lb.? $$\frac{5}{(18+4+9+5)} = 1.58$$ lbs. per square inch. $$\frac{5}{(18+4+9+5)} = 1.58$$ lbs. per square inch. Weight of ball, 40 line; lever, 7 line; valve, 2 line; distance from fulcrum, ball, 80 inches; centre of gravity of lever, 18 inches; centre of valve, 2 inches. Pressure of steam, 70 lbs. per square inch. What should be the distance from fulcrum? $$\frac{70}{(80+7+2+18+2)} = 1.54$$ lbs. per square inch. Distance from fulcrum: $$\frac{70}{(80+7+2+18+2)} = 1.54$$ lbs. per square inch. The diameter of a safety-valve is $X$, and it has three-eighths-of-an-inch deep, and has a level of 5 degrees. What is the area of opening, for a lift one-quarter of an inch? $$\frac{X}{(X-5)} = 1.54$$ lbs. per square inch. The distance from fulcrum to valve is $Y$. What is the area of opening for a lift one-third of an inch? $$\frac{Y}{(Y-5)} = 1.54$$ lbs. per square inch. The distance from fulcrum to valve is $Z$. What is the area of opening for a lift one-half of an inch? $$\frac{Z}{(Z-5)} = 1.54$$ lbs. per square inch. A safety-valve gives an opening of two square inches. What should be its diameter? $$\frac{2}{(2-5)} = 1.54$$ lbs. per square inch. $$\frac{2}{(2-5)} = 1.54$$ lbs. per square inch. $$\frac{2}{(2-5)} = 1.54$$ lbs. per square inch. $$\frac{2}{(2-5)} = 1.54$$ lbs. per square inch. $$\frac{2}{(2-5)} = 1.54$$ lbs. per square inch. $$\frac{2}{(2-5)} = 1.54$$ lbs. per square inch. $$\frac{2}{(2-5)} = 1.54$$ lbs. per square inch. $$\frac{2}{(2-5)} = 1.54$$ lbs. per square inch. $$\frac{2}{(2-5)} = 1.54$$ lbs. per square inch. $$\frac{2}{(2-5)} = 1.54$$ lbs. per square inch. $$\frac{2}{(2-5)} = 1.54$$ lbs. per square inch. $$\frac{2}{(2-5)} = 1.54$$ lbs. per square inch. $$\frac{2}{(2-5)} = 1.54$$ lbs. per square inch. $$\frac{2}{(2-5)} = 1.54$$ lbs. per square inch. $$\frac{2}{(2-5)} = 1.54$$ lbs. per square inch. $$\frac{2}{(2-5)} = 1.54$$ lbs. per square inch. $$\frac{2}{(2-5)} = 1.54$$ lbs. per square inch. $$\frac{2}{(2-5)} = 1.54$$ lbs. per square inch. $$\frac{2}{(2-5)} = 1.54$$ lbs. per square inch. $$\frac{2}{(2-5)} = 1.54$$ lbs. per square inch. $$\frac{2}{(2-5)} = 1.54$$ lbs. per square inch. $$\frac{2}{(2-5)} = 1.54$$ lbs. per square inch. $$\frac{2}{(2-5)} = 1.54$$ lbs. per square inch. $$\frac{2}{(2-5)} = 1.54$$ lbs. per square inch. $$\frac{2}{(2-5)} = 1.54$$ lbs. A table showing various angles and sizes for calculating safety-valve openings. The following table will be found useful in connection with the last two rules, and examples illustrating the application of the formulas are appended: Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Code Size Angle Angle Co...  180 **BOILERS, STEAM.** 7. A safety-valve has a head of 38% of its depth of seat on one-quarter inch, and is required to give an area of opening of 2 inches, with a lift of half an inch. What should be its diameter? $$2 = \frac{3}{4} \times 16 \times (0.35)^2 \times (0.04)^2 \times 0.819 = 1.81 \text{ inches}$$ $$\frac{3}{4} \times 16 \times (0.35)^2 \times (0.04)^2 \times 0.819 = 1.81 \text{ inches}$$ Instead of weights, springs are sometimes employed to hold down safety-valves. The calculations, involving the weight of the valve and the spring, and the steam-pressure, are the same as those previously employed, except that the tension of the spring is to be substituted for the weight of the ball, and the area of the valve is to be substituted for the area of the ball. In order to determine the dimensions of a spring most suitable for a given case, it is easy to calculate the dimensions of a spring for any other desired area. For instance, the cross-section of a spring adapted to one pressure on the valve, make a proportion, thus: Cross-section of first spring : Pressure on valve Cross-section of second spring : Pressure on valve The pitch of the second spring, or the distance from the centre of one cell to the centre of the next, is found by the following proportions: Pitch of first spring : Side of a square equal $$\frac{\pi}{4}$$ (Side of a square equal) (Area of a square equal) Pitch of second spring : Area in area to section giving rise to required spring. Example.--It is a common practice in proportioning the parts of direct-acting spring safety-valves to use a spring of the following dimensions: for a valve 8 inches in diameter and 100 lbs. steam-pressure, use a spring 1 inch thick and 1 inch wide; for a valve 6 inches in diameter and 50 lbs. steam-pressure, use a spring 1 inch thick and 1 inch wide; for a valve 4 inches in diameter and 25 lbs. steam-pressure, use a spring 1 inch thick and 1 inch wide; for a valve 2 inches in diameter and 10 lbs. steam-pressure, use a similar spring for a valve 9 inches in diameter, and a steam-pressure of 30 lbs. per square inch. Area of first valve Area of second valve Area of third valve Area of fourth valve 7.07 inches 509 509 509 Multiply by steam-pressure. 509 509 509 Total pressure on first valve. 184.6 inches 509 509 Multiply by steam-pressure. 509 509 509 Total pressure on second valve. 509 509 509 To find cross-sections of required springs: Pitch of second spring :: 307 :: 968 and, by the rule for proportion, the product of two extremes (307, 968), divided by the third term (707), will give us the fourth term. Now, $$\frac{307}{707} \div 968 = 0.34724$$ which equals cross-section of second spring. The equation $$\frac{3}{4} \times 16 \times (0.34724)^2 = 0.389$$ and this is the side of a square equal in area to cross-section being. To find pitch of second spring : $$\frac{3}{4} \times 16 \times (0.34724)^2 = 0.389$$ Here we solve the problem by multiplying by $$\frac{3}{4}$$ and dividing by the product by $$\frac{3}{4}$$ which gives $$\frac{3}{4} \times 16 \times (0.34724)^2 = 0.389$$ In order to determine how large a safety-valve is required for a boiler, the maximum evaporations must be known; but when these are not known, it is necessary to make some experiment for any special case, but the following numbers can be safely used in general practice: The number of pounds of water evaporated per hour is equal to the area of the grate in square feet multiplied by $$\frac{1}{2}$$ times its height in feet; for stationary boilers with open draught; $$\frac{1}{2}$$ times its height in feet; for stationary and marine boilers with forced draught; $$\frac{1}{2}$$ times its height in feet; for stationary and marine boilers with forced draught; $$\frac{1}{2}$$ times its height in feet. Numerous experiments have been made to determine the opening required to discharge a given weight of steam per hour, and the following rule, while not absolutely correct, gives results that can be used with confidence. $$A = \text{Area of opening}, \text{in square inches}$$ $$P = \text{Weight of steam}, \text{in pounds}, \text{per hour discharged per foot}$$ $$F = \text{Opening area}, \text{in square inches}, \text{in pounds per square inch}.$$ $$A = P \times F$$ Example.--Suppose that a boiler evaporates at the rate of water per hour, what should be the area of opening afforded by the safety-valve, so that the pressure shall not exceed 100 lbs. per square inch ? Absolute pressure in lbs. = 100 + 14.7 = 114.7 $$A = \frac{51.43 \times X^2}{X^2 - X^2} = 0.389 \text{ square inch}.$$ When a safety-valve is raised by the pressure of the steam in a boiler, it usually exposes more area than it requires; hence, if the valves were lowered when they were opened before they were closed, it would be unnecessary to raise them again due to the action of steam on their increased area. It is found in practice, however, that the ordinary safety-valve only rises very  BOILERS, STEAM. 181 sightly when the pressure for which it is set is reached, and that it is necessary for this pressure to be increased considerably to raise the value much higher. With the opening of the valve, steam begins to escape from the boiler with a high velocity, and in its escape it has to overcome the resistive effect of the spring, which is compressed by the weight of the valve. Although there is a greater area of valve to be acted on by the steam, the pressure is reduced. How much the pressure will be reduced in any given case can only be determined by experiment, since the data are therefore not available. In general, however, it may be said that in the case of a 5-inch valve, relieving a boiler at a pressure of 30 lbs. per square inch, the pressure made by the steam will be about 25 lbs. per square inch. The velocity of the steam when opened will vary with the form of valve and the pressure in the boiler, as a change in the valve area will cause a corresponding change in the velocity with which the steam issues from the orifice. In the case of a safety-valve kept down by a spring, it must be remembered that movements and changes in temperature will affect its action. When the valve is opened, it will lift but slightly, since every increase of lift requires additional force for the extension or compression of the spring. But in raising a heavy weight by means of a lever, it is possible to apply more force than would lie to find what pressure is acting when the valve is opened. It will then be possible, knowing the amount of lift required to open the valve, to determine how much force must be applied to the open valve that the steam-pressure will balance the resistance. It must be remembered in this connection that it is desirable to have the valve lift promptly and with little resistance, and indeed so that it will not lift until there is ample room within wide from the pressure due to the increased area, will be prevented, from same cause, from closing until the pressure equals that which it was designed to maintain. Numerous special forms of safety-valves have been devised, some of which are illustrated below. For extensive information concerning these valves see "Steam-Boiler Safety Valves," Com- mission appointed by Congress to examine life-saving inventions, 1868. Transactions of the Insti- tute of Mechanical Engineers, vol. 74, pp. 109-120; "Report on Steam-Valves," vol. 103, pp. 109-120; "Report on Safety-Valves by a Special Com- mission of the Board of Supervising Engineers," 1871. A large number of patents have been issued con- cerning these valves, many of them being repre- sented by the latter committee, and their recommendations are here adopted. Fig. 416 represents an ordinary lever safety-valve. The rule given below may be tested in connection with the other values. It will be observed that the ac- cumulation of water in front of the valve pre- vents motion from sticking. It should be noted that ordinary safety-valves, when discharging at different pressures, do not follow this rule exactly. The fol- lowing rule for calculating the area of valve that will give the required area of open- ing for any given rate of flow is based on the number of pounds of water evaporated per hour by 0.005; the product will be the area of valve in square inches. This rule gives a smaller area than would be obtained by trial and error calculations. It is well to remember that the valves used by the committee were constructed especially for the experi- ment, and that they were not intended for general use. The committee recommend that Prof. Ralston will probably be safer for general use. It may be added that rules of this form are ex- actly safe only for general use; our ordinary formulas giving very different results, as shown by experiments made by us on several occasions during our stay in England. In fact, all such experiments were made at a pressure of 30 lbs., would be: For the rule of United States Board of Inspection and Survey (see page 24), for those given by Hallowell (1838), for first given by Prof. Treadwell (1845), for those given by Prof. Ralston (1856). The committee recommend that no one should rely upon these rules without further examination. 10. Attention has been directed to discrepancies of these rules on several occasions; and in spite of the distinguished authority on which they rest, it is reasonable to hope that all but the best known authorities may have been found wanting. The committee observed that, where very large valves are used, their construction should be considered carefully; they should not be allowed to operate under conditions requiring them to be lifted by a kind of lifting of the valve; and they fix at limit as having an area of 10 square inches or less; recommending that two or more valves be used, when a greater area than 10 inches is required. The valves offered for test were divided by the committee into six classes, according to their construction: 1. Restraining-safety-valves, in which the escape of steam is opposed by a pin or striker, as shown in Fig. 417. 2. Double-lever-valves in which a disk is secured to each valve having a greater area than the valve, so as to force the valve farther from its seat when it opens. Fig. 418 is an example of this class. Annular safety-valves, with two seats upon an annular opening (as shown in Fig. 419), with a view of obtaining a greater area opening for a given lift. A diagram showing a lever safety-valve. 416  183 **BOILERS, STEAM.** A. Double-seated safety-valves, of the same general form as the double-puppet-valve, the upper and lower parts being of different sizes, so that they can readily and completely close at the time of opening. See Fig. 420. B. Common orifice-valves, which are assisted in their operation by small auxiliary valves or a combination of levers. One of this class is shown in Fig. 421. A diagram showing a double-seated safety-valve with two distinct sections. A diagram showing a common orifice-valve with an auxiliary valve. 6. Piston safety-valves (see Fig. 423 for an example of this class), in which a piston connected with the valve assists it to rise. A universal lever was adopted for all these valves. Each was attached, in turn, to the boiler, was set to blow off at 30 lbs., and was allowed to operate for 10 minutes, with a strong fire A diagram showing a piston safety-valve with a piston and connecting rod. A diagram showing a piston safety-valve with a lever and connecting rod. in the boiler, was then set to 70 lbs. pressure, and the experiment was repeated. The following table gives a summary of the results obtained with 12 of the competing valves, and 2 of the common valves constructed by order of the committee. The table in the report contains results of the list of Valve Type Results Double-seated Safety-Valve ... Common Orifice-Valve ... Piston Safety-Valve ...  BOILERS, STEAM 183 It will be observed that some of the special forms of valves, with considerably larger areas of opening than ordinary valves, allowed the pressure to increase as much or more. This is prob- able due to the fact that the very form by which the greater lift was obtained made it more difficult to close the valve, thus allowing a greater amount of steam to escape during the period of its operation. In the case of several experiments with the same valve, where the table shows considerable difference in the results, it is evident that the form of the valve had a decided effect on the results. The following table gives the results of several experiments with different forms of valves, and indicates the action of the valve when properly adjusted. This remark applies both to the common and special forms of valves. There is one peculiarity, quite an important one, which the table does not show, namely, that the pressure at any given time is not constant. With the common valves, when the valves open, the pressure gradually increases to the maximum, and then decreases again until it reaches a point below atmospheric pressure, when they are closed. With nearly all the other valves, however, after the valve opens, the pressure falls below the normal atmospheric pressure. This fall may be gradual or sudden. In some cases it may continue for several minutes, in the course of a 10 minute trial; and sometimes the pressure fell off at once and the valve blew off at a less pressure than that at which it was set, during the whole trial. It is evident that this is not a desirable condition for a safety-valve. The results of these experiments are shown in Table II., and the records of the trials seem fully to confirm the opinion stated in the report, that the common form of safety-valves are not adapted for use on locomotives and steamers in rough water, owing to their tendency to blow off under certain conditions. For use upon locomotives and steamers in rough water, some of the special forms of valves have been found satisfactory. The following table shows how well they perform on stationary engines (see also page 175). On stationary engines, safety-valves are usually set so that they will blow off at a lower pressure than they would on locomotives or steamers. The reason for this is that on stationary engines there is no danger of overloading them with steam. On locomotives and steamers, however, there is always a possibility of overloading them with steam. The best manner of loading a safety-valve has been the subject of animated discussion among engi- neers. Some say that it should be loaded with steam only up to a certain point; others say that it should be loaded with steam up to a certain point; and still others say that it should be loaded with steam up to a certain point. The best way to load a safety-valve is to load it with steam up to a certain point; and still others say that it should be loaded with steam up to a certain point. The soundness of this statement can be seen by looking at Fig. 42. In this figure we see two diagrams showing how steam enters into a boiler through a pipe connected to the exhaust-pipe, and how steam leaves from non-condensing engines are frequently objectionable. Figs. 43 and 44 show how steam enters into a boiler through a pipe connected to the exhaust-pipe, and how steam leaves from non-condensing engines are frequently objectionable. Figs. 45 and 46 show how steam enters into a boiler through a pipe connected to the exhaust-pipe, and how steam leaves from non-condensing engines are frequently objectionable. The construction will doubtless be evident from the figures. In Fig. 42 it will be noticed that the steam, instead of escaping from the end of pipe, is discharged through numerous small holes in the bottom plate of the boiler. This prevents any appreciable loss of heat from the passage of the "pans," all these minor vibrations are absorbed by each other's coils of wire." Walter H. Gage says: "In my experience I have found that first the ordinary gauge-cock, second the gauge gauge, and third the third float. The gauge-cocks on being turned, allow air to enter into each other's coils of wire." He further states: "I have found that three gauge-cocks inserted in each boiler, at different levels; and the rule is to so feed the boiler that there will be steam in top gauge-cock, and water in other two. The gauge gauge consists 184 **BOILERS, STEAM.** of a glass tube set in front of the boiler, communicating in its upper portion with the steam-room, and in its inferior portion with the water within the boiler, the position of the tube being so adjusted that the water-level stands at about the middle of its length. The tube is connected at the top and bottom to a glass gauge, which is graduated in inches, and is provided with cocks, so that the tube may be blown through by the steam when the boiler is filled with water, and also to allow air to escape from it. If the glass breaks, it is unsafe to treat to the glass gauge altogether as a means of ascertaining the water-level, as insufficient pressure will cause it to stand high in the tube though it may have sunk low in the boiler. In such case, however, if a partial vacuum be produced, the glass gauge becomes of especial value, as it will indicate whether in such a case, for, though opened, neither steam nor water will come out, but air will rush in. This sometimes occurs when a boiler is filled with water at too low a temperature. The gauge contains of a float resting on the surface of the water, and communicating with an index, so that the fluid level can be read directly from this index, made apparent. The float is usually of stone or cast-iron, but is so balanced as counter-weight as to make it self-balancing under all conditions of tempe- 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472A SHARPE'S WATER GAUGE BOSTON. stand-pipes are constructed in their diameter below the level at which the damper-plate usually operates, and danger has arisen from this cause, for the fluid has descended into this narrow neck when there was a surplus of steam in the boiler, and by stopping up the passage it has prevented the access of the feed-water. This danger should be so regulated as to avoid accidents of this description. **Ashcroft's Dampers Water-Gauge (for use on steam-boat boilers), consisting of a non- magnetic needle floating in a chamber of the gauge, which controls a nozzle on a dial graduated by dividing the connection between the two being entirely separate.** Fig. 435 is a front view of the dial, showing the needle and graduation scale. Fig. 436 is an en- A SHARPE'S WATER GAUGE BOSTON. view of the gauge, as if a cover plate had been at- ached to a brass rod R, which passes through a hole in the side cham- ber of the gauge, on the end of which is affixed a steel magnet, having two insulated negative poles. The rod plays in the space between these poles, having no stuffing box, valve connection, or packing of any kind about it; hence there is no friction. The needle on the dial moves on a polished silver pin, and is controlled by this magnet. It will instantly indicate the level of solid water. Fousing or priming has no effect upon the gauge. The scale on the dial will indicate a rise or fall of 12 inches of water, each degree measuring 2 inches.  BOILERS, STEAM. 185 The accompanying engraving (Fig. 439) represents Hopt's water-gauge, partly in section. It is a simple mechanical invention for telling, at all times, the position of the water in steam-boilers. The dotted circles show the connection with the boiler; the cock at the bottom is a blow-out cock for the purpose of blowing out any air that may have been introduced into the gauge by mistake. The gauge shows indication of the solid water within the boiler, the foam not being dense enough to move or affect the float, so that it will always remain in the same place, and thus give a constant indication of the position of the water. The float is also directly connected with the inclining hand, by means of a wire and spring, so that when the float rises or falls, the inclining hand moves up or down upon its surface. The float is also directly connected with the inclining hand, by means of a wire and spring, so that when the float rises or falls, the inclining hand moves up or down upon its surface. This is necessary to prevent the inclining hand from moving about the shaft, to prevent its always working with perfect ease and accuracy. No packing is needed, as the shaft, in passing through the case to connect with the indicator, forms of itself a perfect seal against leakage. It is easily applied to all kinds of steam-boilers, locomotive, stationary, and steamboats. A diagram showing a steam gauge with a float and a connecting rod. 439 The Nicholas water-gauge, Fig. 439, is designed to show the height of water in a boiler, when located at any level and at any distance from the boiler. It consists of two parts: one part is a glass tube, from which water is drawn into a cylinder, and connected to a cylinder interposed between the boiler and its cover; this cylinder contains a liquid which is used for indicating purposes. The other part is a detached gauge filled with water to any convenient height, and some colored fluid is introduced into the space above the water, so that, when the water-level changes in the boiler, it changes to the same degree in both parts of the gauge. When this happens, a line on one side of each part of the gauge indicates the amount of change. Steam-gauges are commonly used for indicating the pressure of steam, water, air, and other fluids, may be divided into two classes: gauges in which the pressure is measured by the motion of a piston or diaphragm; and those in which it is measured by a column of liquid, such as mercury. In all forms of steam-gauges, the connecting-pipes is generally bent, so that the part next to the gauge shall always contain water when in use, in order that the steam may not escape before it reaches this part; but in those gauges in which the pressure is transmitted by action within the springing or against the spring through the diaphragm or piston. Both varieties are illustrated on page 168. Fig. 439 shows one form of the well-known Bourdon gauge; in this gauge a thin metal tube is bent into a curve; when pressure is applied to such a tube, the tendency is to change the flattened section into a circle, and thus to straighten the tube, so that an indicating-hand attached to end of tube will be moved along scale. This A diagram showing a Bourdon gauge.  186 **BOILERS, STEAM.** form of gauge is sometimes arranged as shown in the figure, so that its accuracy can be tested at any time by hanging a weight at the point indicated. The dial of the gauge has a working-scale, for reading the pressure, and a second scale, for indicating the position of the pointer with respect to connection with the weight. The gauge is tested, with the steam-pressure acting upon it, by hanging A diagram showing a gauge with two scales: one for reading the pressure and another for indicating the position of the pointer. on the weight, when, if the hand falls back to the same figure on this scale as that in which it stood on the working-scale before adding the weight, it indicates that the reading of the gauge is correct, while any variation from the former reading shows the amount of error. An improved form of the Bourdon gauge is illustrated in Fig. 435. It consists of a Bourdon tube connected to a bellows, to which is attached an indicating mechanism. Fig. 436 illustrates a spring of another variety of gauge, which consists of two corrugated plates connected by a curved band. All the parts of this spring are made of metal, and when the pressure acts on one plate, the pressure is transmitted to the springs through elastic diaphragms. In Fig. 435 a coiled spring is employed, and in Fig. 434 there is a plunger resting on elastic packing, the movement of this plunger being communicated to a pointer. Spring-gauges are tested either by a mercury column or by hydraulic pressure from a test-pump, to which another gauge, known to be correct, is attached. The square-dish test-gauge, Fig. 437, is designed to be a cheap and simple substitute for the centil test-gauge. It consists of a valve exactly one square inch in area, a needle which can be connected with a test-pipe or with a mercury column, and a bulb so as to load the valve to any desired extent, so that when the apparatus is connected to a test-pipe, the pressure may be varied at will. Edison's recording steam-gauge, Figs. 438, 439, not only indicates the pressure at every instant, but also makes a record showing what the pressure was at any particular time and gives an alarm if the pressure exceeds a certain limit. The gauge consists of a cylinder in the form of a corrugated steel disk, and a pencil attached to the indicating-hand presses against a strip of paper fastened round the circumference of the cylinder. The pencil moves over the paper form a pressure-scale, and vertical divisions indicate a scale of time, as will be evident from an illustration of it in Fig. 440. When the pressure exceeds a certain limit, which can be fixed at pleasure, a bell attached to the gauge commences to ring, and at the same time connection is made with an electric bell situated elsewhere on board ship or engine-room. This electric bell rings until the pressure is reduced to within limits. To obtain the record of pressure during an experiment, as for instance, the steam-pressure in a boiler-test, or the water-pressure in the trial of a pumping-engine, the paper is made to move as far as possible under A diagram illustrating Edison's recording steam-gauge. the influence of gravity.  BOILERS, STEAM. 187 then by ordinary use. It will be seen that this gauge maintains a constant watch on the safe and skill of the boiler-attended, and might be very useful in the case of a disastrous boiler-junction, where no witnesses are present to witness the accident, or even at the time of the accident. The instrument is covered by a glass dome, which may be secured by a spring and catch, preserving the diagram in view. In the other class of pressure-gauges to which attention has been made, the pressure is indicated by a column of heavy liquid, usually mercury. This siphon-gauge, Fig. 440, is the form commonly employed for showing low pressures. It is merely a tube con- taining mercury, one end of which being connected with the boiler, and the other being open. A light stick is placed on the mercury in the two siphons, by falling or falling, when the end of the column is influenced by the pressure, a change is communicated to the siphon corresponding to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inch; or to a pressure per square inches. 456 In the ordinary siphon-gauge, the height of the mercury column indicates the amount of force exerted upon it. A rise of one-inch corresponds to this press- ure since, for each rise in one branch of the siphon, there must be an equal fall in the other. Hence, if the pres- sure forces mercury up one-inch in one branch of the second siphon-gauge, it will rise half an-inch in the first, one-quarter of an-inch in the third siphon, and so on down through all branches until no more gage for showing high pressures but consists of several branches of series of siphons filled with mercury, arranged in such manner that they can be opened and closed separately the several mercury columns. In the counter-steam-gauge (a glass tube is inverted in reservoirs of mer- cury) the level of the mercury in each branch is regulated by means of valves. The rise in the tube nearly reaches that surface (but slightly lower, owing resistance of air in the glass tube). As soon, however, as the pressur communicated exceeds that of atmosphere, A diagram showing how water levels are measured in boilers. 457  188 **BOILERS, STEAM.** the mercury will be forced up into the tube, and the heated air condensed, until its elastic resis- tance is just equal to the pressure. The height of the mercurial column will of course vary with any variation of pressure, and thereby indicate the degree of pressure at every moment by means of the scale, which is to be taken according to the barometric or atmospheric pressure of the time. A diagram showing a barometer with a scale indicating pressure levels. 480 A diagram showing a barometer with a scale indicating pressure levels. 481 The high degree of pressure to which the last-described form of manometer may be subjected with- out error from friction or loss of mercury, the permanent elasticity, and the everywhere existing and exactly defined qualities of the material of resistance (atmospheric air, or other fluid) in the same tube, make it a very desirable instrument for meas- uring atmospheric pressure. This form is simple and conven- ient form, make it a very desirable instrument for meas- urement of atmospheric pressure. It has been constructed, however, it has defects, which have prevented its general use as a practical instrument. One defect is that the coating and consequent quality of the glass tube, by the deposition on its outside, causes a certain amount of induced resistance; so that the expansion and partial loss of air from within the tube whenever any partial vacuum is produced in the tube, causes a corresponding increase in mercury in the tube above the mercury; its coefficient of expansion is greater than that of mercury; as in engines working expansively; the almost constant temperature of the atmosphere; and finally, the violation between the mercury and the glass, and to find its way into the tube above the mercury; and the great inequality in the diameter of the glass tube, which is contrary to the law that governs the volume of air under fluids. Some improvements, designed to correct these defects, were proposed, some years ago, by Mr. Paul Stillman, of New York. Fig. 441 is the usual form of the patent manometer for showing atmospheric pressure. Fig. 442 represents the form of one for showing a vacuum. Fig. 443 is in the form used for showing less than 1 as- tream. Fig. 444 is in a longitudinal section through the centre of a manometer for showing less than 1 as- stream in which the tube is firmly secured by means of the stuffing-box O. A cap P is screwed into this box to pre- vent the escape of air from below. A screw B is inserted in the brass one C, and in the middle to confine it in the reser- voir D. The cover E is fastened on by screws F. The tube G is to be immersed. D D are scales divided into atmospheres, pounds, or inches of pres- sure, as desired. B are blocks to secure the scales in their proper places. P is a plug for admitting air into the reservoir D. A cap H is screwed into this box to prevent air from entering through the opening of the screw; prevent its oscillation, and at the same time allow the orifice to be made to admit more or less air as required. In Fig. 441 the reservoir for mercury is a deep cell, with an iron tube communicating from the cock at the bottom to the middle of chamber above surface of mercury. In Fig. 443 it is A diagram showing a manometer with a scale indicating pressure levels. 482 A diagram showing a manometer with a scale indicating pressure levels. 483  BOILERS, STEAM. 189  190 **BOILERS, STEAM.** In Shaw's gauge, Fig. 443, there is a double-headed piston, on the small head of which the steam presses, and the large head transmits this pressure to an open mercury column. The heads are A diagram showing a double-headed piston gauge with a mercury column. separated from the steam and mercury by rubber diaphragms, so that the piston can be fitted loosely, without any tendency to leak. The Stiles gauge, Fig. 444, is a model of simplicity and accuracy, no packing being used in its construction. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron cylinder fits loosely into another cylinder containing the steam and mercury. A large iron Cylinder fittingly contains a water level indicator, which gives warning, usually by blowing a whistle when the water-level falls below a certain point; they depend generally for their action upon a float or a float which opens a whistle-valve when it is immersed in water in the boiler, or on the direct pressure of steam, which is only effective when it acts upon a float when the water-level is depressed, or on a lever which is moved by rotation of a toothed wheel when exposed to contact with steam instead of water. Fig. 447 is a fuselame, a flat annular plate or rod which passes upward through a hollow pipe C of the steam-valve D. The lower end of the whistle P is passed through an orifice in the top of the boiler (indicated by letters e), and screwed into the top of the tube, A diagram showing a fuselage with a whistle valve.  BOILERS, STEAM. 191 which is thus kept steady, if it is a vertical position. It is a wire attached to the stem of the float, near the top, which, catching against the plane $A$, on the fall of the stem $A$, prevents it from descending farther. When the water falls below the level of the wire, the wire will be pulled down, and the steam will escape, impinging against the $B$ of the bell apparatus, and causing it to ring. One form of an alarm which acts by expansion is illustrated in Fig. 448, which represents a boiler with a double tube. This is necessary for our description. A tube descends into the boiler just below the prop-water-line, and is secured to the sides. The bottom of this tube is connected into which two tubes, $B$ and $X$, are fixed. The upper end of these tubes is connected into a fixed level at the proper temperature of the boiler. In the tube $X$ is a wire so arranged that when the water rises it should be of platinum, will come just above the working level of the boiler. The upper end of this tube is at such a height which will be caused by the heat which would cause it to rise, and will be equal to the pressure of steam in the boiler; and at starting, the apparatus is so adjusted when the steam is at the working-pressure in the boiler, and when the wire is in the tube $X$ proceeds the wire to the bell-apparatus $P Q$ for the purpose of ringing a bell. The wire is connected to a battery $A L$. By this arrangement, when the heat in the boiler rises above a certain point, and causes the water to boil, and steam to escape from the boiler, the quicksilver expands, and coming in contact with the platinum wires, completes the electric circuit, and the bells will "ring" as soon as they have reached their maximum temperature at night. Plugs of fusible metal are very often used as low-water alarms, being A diagram showing a boiler with a double tube system for detecting low water levels. (FIGS. 435 AND 436 ARE COPPER BOILERS.) (A BELL APPARATUS FOR STEAMBOAT INDEPENDENCE.) 435  102 BOILERS, STEAM. screwed into some portion of the boiler directly over the fire, so that if the plate becomes overheated on account of the heat being too great, the steam will escape, and thus prevent the boiler from becoming dangerous to life and limb. The purpose of this device is to protect the operator from the danger of his own carelessness, and to enable him to attend to other matters which may come under his immediate notice without fear of injury from the boiler. **Damper-regulator—These devices are designed to control the draught mechanically, closing the damper when the pressure falls below a certain limit, and opening it as the pressure falls. Although there have been many attempts at inventing such an instrument was first introduced in this country, its essential features having been patented by Mr. W. H. B. Clark, in January, 1864. Both figures are in section. The construction of this device is shown in Fig. 438, from which it will be seen that a valve is attached to the damper, and that from the boiler is introduced beneath a valuated rubber diaphragm, which is connected with a lever, like a common safety-valve, to its lever $H$, to which a spring is attached. When the pressure falls below a certain point, the diaphragm closes the damper in the chimney or flue. Fig. 439 shows the position of the diaphragm and piston when the pres- sure is at its maximum. The diaphragm and piston are then raised by means of a spring, and when the pressure ceases that which is desired, the diaphragm and piston are returned to their original positions by a spring, until it attains the position, Fig. 439, when the draught is regulated. In this case it will be seen that the regulation of the draught is controlled by the sliding weight or pin on the steel- arm $A$, as shown in Fig. 438. The diaphragm is composed of two pieces of metal, and that any desired amount of motion may be given from $A$ to $B$. This movement is limited by a stop, but for a movement not greater than one-eighth of an inch, however, provided that a flat disk will an- swer, provided that cylinder $C$ does not move in the figure. In some forms of these instruments recently introduced, cor- rective movements are pro- vided instead of a piston or plunger. **Boilers—The illustrations of boilers are from Mr. F. E. Bowers's "Steam Engineering," Figs. 451 to 664 will give you an idea of past and present practice. In 1827, Rob- ert L. Stevens & Co., con- structed a pair of boil- ers for steamship Independence, which ran between South America and New York. Of these Figs. 451 and 453 are correct repre- sentations, the form of which has been adapted to the burning of anthra- cite coal by means of bellows, or what is commonly called the fan. No difficulty was ever found in the accom- plishment of these purposes they were intended to show how many improvements have since that time been adopted; they are still working satisfactorily. To Mr. Stevens due credit of first establishing the water-cylinder, which serves as a purpose of protecting the mouth of these tubes. A diagram showing a cylindrical boiler with a dome-shaped top. 438 A diagram showing a cylindrical boiler with a dome-shaped top. 439 [Fig. 438.—The steamboat New York built by H. H. Duryea & Co., has one copper boiler with two fireplaces and two furnaces; each furnace has three fireplaces; each fireplace has four burners; each burner has three tubes; each tube has two nozzles; each nozzle has two nozzles; each nozzle has two nozzles; each nozzle has two nozzles; each nozzle has two nozzles; each nozzle has two nozzles; each nozzle has two nozzles; each nozzle has two nozzles; each nozzle has two nozzles; each nozzle has two nozzles; each nozzle has two nozzles; each nozzle has two nozzles; each nozzle has two nozzles; each nozzle has two nozzles; each nozzle has two nozzles; each nozzle has two nozzles; each nozzle has two nozzles; each nozzle has two nozzles; each nozzle has two nozzles; each nozzle has two nozzles; each nozzle has two nozzles; each nozzle has two nozzles; each nozzle has two nozzles; each nozzle has two nooz  BOILERS, STEAM. 193 Fig. 484 and 485 represent boilers of the Rolls, built by T. F. Scou & Co., which had one engine of 3-inch cylinder, 10 feet stroke; 186 cubic feet in cylinder, which gave, in proportion to the boiler, 1-1/2 to 1. Used anthracite, with a blower. A diagram showing the interior of a boiler. Fire-Surface in this Boiler. In the steam chimney. .................................................. 12,000 front connection. ........................................................... 7,000 return connection. .......................................................... 477,005 back connection. ............................................................ 114,000 inside flue. ..................................................................... 818,008 furnace, bridge-wall, etc. ................................................. 1,297,185 Total number of square feet in boiler. .................................. 2,875 A vertical water-tube boiler patented by D. B. Martin was used almost to the exclusion of every other form in the United States for many years. It differs from the Earl of Dunstanfield's boiler in that it has no firebox and no grate; but the most important of all the experi- ments ever made was the trial, in 1863 and 1864, by a board of engineers, of the vertical water- tube boiler on the principle of Martin's patent. The results were favorable to the gen- eral practice, and with various modifications. A full summary of these experiments will be found in papers published by the American Society of Mechanical Engineers. It is probable that at that time, the best examples of standard practice, and the proportions of the horizontal fire-tube boiler were essentially the same as at present. The boilers are illustrated in Figs. 486 to 489, and the principal dimensions are as follows: Name of Valve Time of Valve Set to Open at 25 Pounds Set to Open at 30 Pounds At Least Amount Required At Least Amount Required At Least Amount Required At Least Amount Required Ashworth 1st Trial 1st Trial 1st Trial 1st Trial Crosby 1st Trial 1st Trial 1st Trial 1st Trial Crosby 2nd Trial 2nd Trial 2nd Trial 2nd Trial Crosby 3rd Trial 3rd Trial 3rd Trial 3rd Trial Crosby 4th Trial 4th Trial 4th Trial 4th Trial Crosby 5th Trial 5th Trial 5th Trial 5th Trial Crosby 6th Trial 6th Trial 6th Trial 6th Trial Crosby 7th Trial 7th Trial 7th Trial 7th Trial Crosby 8th Trial 8th Trial 8th Trial 8th Trial Crosby 9th Trial 9th Trial 9th Trial 9th Trial Crosby 10th Trial Horizontal Fire-Tube Boiler Vertical Water-Tube Boiler Length 190 ft. 190 ft. Width 2 ft. 2 ft. Number of rows 3 3 Length of row 66 ft. 66 ft. Width of row 4 ft. 4 ft. Total number of tubes 276 276 Leverage of tubes 5 ft. 5 ft. Number of tubes per row 96 96 Total number of tubes 96 96 Diameter of tubes (outside) 2 in. 2 in. Diameter of tubes (inside) 1-3/4 in. 1-3/4 in. Bending-elevation (outside) 2 in. 2 in. Bending-elevation (inside) 1-3/4 in. 1-3/4 in. Tubes per row (outside) 96 96 Tubes per row (inside) 96 96 Total number of tubes (outside) 96 96 Total number of tubes (inside) 96 96 Area-space in general: Total area space (outside) Total area space (inside) Cross section of chimney: Length of chimney: Weight of boiler: Total weight: The general result of the experiments was to show that, as the boilers were constructed, the verti- cal water-tube boiler was the most economical, but as rapid a rate of combustion could not be main- 15 $8,400 lbs. The general result of the experiments was to show that, as the boilers were constructed, the verti- cal water-tube boiler was the most economical, but as rapid a rate of combustion could not be main- 15.  194 BOILERS, STEAM. tained in it as in the other, with natural draught. In varying the proportions, however, it was found that by removing a sufficient number of the vertical tubes, the water-tube boiler could be made to burn coal at the same rate as the fire-tube boiler, and with about the same economy. This A diagram showing the arrangement of a water-tube boiler. fact does not seem to have been very generally noticed, but it is well illustrated in the boiler designed by Thoron Skeed, Fig. 409, which seems to have some important advantages over the ordinary water tube boiler. Fig. 465 shows the space at present occupied by the boilers and fire-room of A diagram showing the arrangement of a water-tube boiler with a fire-room. the P. M. R. S. Colon, and Fig. 461 the space required for Mr. Skeed's water-tube boilers to evaporate the same amount of water as the others. The following table illustrates this point more fully : Boilers for Steamship Colon. Mr. Skeed's Proposed Boilers. Water-tube Boilers. Free surface in four boilers 798 sq. ft. 524 sq. ft. Normal draught 84 cu. ft. 84 cu. ft. Cross area to flow 34 34 Width of fire room 84 84 Cross area of space in four boilers and fire-room 13,500 13,500 Total cross area of space 13,500 13,500 Total cross area of space from 187° per hour 94,000 94,000 The objections are sometimes made to the vertical water-tube boiler, that the tube-boxes cannot be cleaned quite as readily as the horizontal tubes, and that a leaky tube in the water-tube boiler cannot be stopped as readily as an horizontal tube; since in the former case water must be A diagram showing the arrangement of a water-tube boiler with a fire-room and tube-boxes. 465 461 469 469 461 469 469 461 469 469 461 469 469 461 469 469 461 469 469 461 469 469 461 469 469 461 469 469 461 469 469 461 469 469 461 469 469 461 469195 Flow from the boiler before the tube can be plugged or expanded. Practically, however, these objections are not very serious. Fig 486, A and B, illustrate the modern marine boiler, which is now in general use. It is a tubular boiler with a cylindrical shell, and cylindrical flues which form the furnaces. In this example the flues are strengthened by ring-joints, as shown at A. The longitudinal seams are strengthened, and the longitudinal seams are made with transjoints, with covering plates on each side. Some of the tubes are of extra thickness, to take the place of longitudinal braces, being secured with nuts at the ends. Fig 488 gives views of a boiler designed by Mr. C. E. Emery, of New York, which is selected as  196 BOILERS, STEAM. A detailed technical drawing of a steam boiler, showing its various components and dimensions. STEAM-BOILER DESIGNED BY G. E. EMERTY, C. E. OF NEW YORK. Copyright 1905 by the American Society of Mechanical Engineers. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission of the ASME.  BOILERS, STEAM. 197 A good example of modern practice. The sectional dimensions will be found on the plan, and the peculiarities of construction are there clearly detailed. The large opening from steam-drum to shell, which ordinarily would be a source of weakness, is strengthened by transverse braces arranged very nearly at the third lines of the struts, the same being crossed simply to permit the passage of A diagram showing the internal structure of a boiler. Boiler Diagram a man above and below them. The connection from drum to boiler is made through oval openings of man-hole size, which do not materially weaken the main shell. The coming of back ends of furnace-tubes into the shell is secured by means of a short flange, which is bolted to the shell at the code, as shown, and pass between angle-grooves, which support the plates. All longitudinal seams and those between the tubes and shell are riveted, and all other seams are stiffened by flanging ends of sections outward, and riveting flanges together through welding rings. The sectional boiler, several varieties of which have been illustrated, and which is now successively used on many ships, is one in which the water circulates under pressure. The efficiency of the tubes being destroyed in a short time, probably on account of imperfect circulation under the usual water level, has led to the adoption of a new form of boiler in which this difficulty is pre- sente. (In the "Transactions of the Institution of Naval Architects," 1874,) is a paper containing an account of this new form of boiler, and also a description of its working. A similar form has been found in Engineering, xxi., and an abstract of it in Chief-Engineer King's Report on European Ships of War. **Improvement of Boilers.—The water-heating surface of a boiler is all the surface which has flame or heated gas from the furnace on one side and water on the other. Surface which has flame or hot gas on both sides is called fire-surface.** The area for the passage of the products of combustion, taken at any section of their course after leaving the furnace, is called passage area. This area may be measured either horizontally or vertically. Ordinarily, when not otherwise specified, the term refers to the area through or around the tubes of fire and water-tube boilers, and through the flue of air blowers, although it is equally applicable, as it is shown in Fig. 306, to all forms of boilers. In some cases it includes also that part of the passage area through which gases pass directly from the furnace to the chimney—a fact which must be considered in designing boilers for ships. In some cases it includes also that part of the passage area through which gases pass from the chimney to the atmosphere; but in most cases it does not include such part. In some cases it includes also that part of the passage area through which gases pass from one part of a boiler to another; but in most cases it does not include such part. In some cases it includes also that part of the passage area through which gases pass from one part of a boiler to another; but in most cases it does not include such part. As has been noticed, the products of combustion turn twice in their passage to the chimney. Examination might be given to still a greater number of deflections of the heat gases. It may be evi- dent that if these deflections could be reduced to zero, i.e., if they did not occur at all (as with any type), dependence upon the amount of air supplied for combustion, and thus upon its governor principally by its own action, would be entirely eliminated; and that this would greatly improve the performance of a boiler in another important particular. When it is very large, the hot gases, in passing over the heating surface, are not broken up and mingled in such a manner as to cause their temperature to fall so rapidly as to prevent their reaching a high temperature before they are exhausted; and this effect is often produced. Until the improvement in the calorimeter was first announced by Chief-Engineer B. F. Burdette (Engineering, xii.), no one had thought that this effect could be produced except upon the rate of heating to the grate surface for any given rate of combustion; and this principle will still be found in many engineering treatises, and will be acted upon to a large extent, in practice. The best rules that can be given for designing boilers are drawn from experience; and the three laws laid down by Mr. Burdette are worthy of careful study by engineers. The following experi- ments that have ever been made, will be of great value to those who study them carefully. A diagram showing different types of boilers. Boiler Diagram  BOILERS, STEAM. Summary of Expenditures with Personal Property, 1884, 1886. REVENUE AND EXPENDITURE $108 PURPOSE OF CONSTRUCTION THE PURPOSE OF WATER PUMPING, FRESH AND BRINE. $108 BOARD OF WATER PUMPING, FRESH AND BRINE. $108 BOARD OF WATER PUMPING, FRESH AND BRINE. $108 BOARD OF WATER PUMPING, FRESH AND BRINE. $108 BOARD OF WATER PUMPING, FRESH AND BRINE. $108 BOARD OF WATER PUMPING, FRESH AND BRINE. $108 BOARD OF WATER PUMPING, FRESH AND BRINE. $108 BOARD OF WATER PUMPING, FRESH AND BRINE. $108 BOARD OF WATER PUMPING, FRESH AND BRINE. $108 BOARD OF WATER PUMPING, FRESH AND BRINE. $108 Purpose of Construction Total Cost Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Board of Water Pumping Fresh and Brine Purposes of Construction Passes of Cistern RELATIVE EFFICIENCY. NATURAL DRAUGHT PURPOSED DRAUGHT Rate of Flow per Hour Rate with Four Feet Fuel Rate with Four Feet Fuel Rate with Four Feet Fuel 1 1 948 1,711 1,469 2 378 504 340 341 3 270 370 280 280 4 192 257 198 198 5 148 191 148 148 6 105 139 105 105 7 753 Construction of Boilers.—The following rules, giving about one-eighth the ultimate strength of the material for the working stroke, and following the proportions recommended by the best authorities, will be found sufficient for all practical purposes. The boiler should be so designed that the steam pressure shall not exceed two-thirds of its ultimate strength, and that the steam pressure shall not be less than half ; but, taking into account the rapid deterioration of steam-boilers, and the violent strains to which they are subjected, it is advisable to allow a margin of safety greater than that here specified. The boiler should be so constructed that no part of it shall be weakened by any defect or lack of thickness which may be permitted, on principles of true economy. The reader will find interesting data relating to this subject in Fairbanks's " Useful Information for Engineers," Haskins's " Treatise on the Steam Boiler," and in the papers read before the Iron Founders' Association, and the English Boiler Insurance Association, "Proceedings of the Institution of Civil Engineers," vol. vi., "Fouling and Corrosion," by J. W. H. Smith, Esq., F.R.I.C.S., 1873; Grashow's "Feuchtigkeitshütte," and "Des Ingénieurs Taschenbuch, von dem Verein 'Hütte.'" Notation. $$E = \text{diameter of rivet, in inches}$$ $$L = \text{length of rivet under head, in inches}$$ $$W = \text{width of rivet under head, in inches}$$ $$P = \text{distance between centres of rivets, in inches}$$ $$F = \text{working pressure of steam, in pounds per square inch}$$ $$L_1 = \text{length of cylindrical plate, in inches}$$ $$L_2 = \text{length of cylindrical flange, in inches}$$ $$R = \text{radius of circular plate, in inches}$$ $$r = \text{radius of rectangular plate, in inches}$$ $$b = \text{breadth of rectangular plate, in inches}$$ $$S = \text{distance between centres of stays, in inches}$$ $$A = \text{area of cross-section of stay, in square inches}$$ 1. Diameter of rivets. $$\frac{E}{2}, \quad \frac{E}{2}, \quad \frac{E}{2}, \quad \frac{E}{2}, \quad \frac{E}{2}, \quad \frac{E}{2}, \quad \frac{E}{2}, \quad \frac{E}{2}, \quad \frac{E}{2}, \quad \frac{E}{2}, \quad \frac{E}{2}, \quad \frac{E}{2}, \quad \frac{E}{2}, \quad \frac{E}{2}, \quad \frac{E}{2}, \quad \frac{E}{2}, \quad \frac{E}{2}, \quad \frac{E}{2}, \quad \frac{E}{2}, \quad \frac{E}{2}, \quad \frac{E}{2}, \quad \frac{E}{2}, \quad \frac{E}{2}, \quad \frac{E}{2}, \quad \frac{E}{2}, \quad \frac{E}{2}, \quad \frac{E}{2}, \quad \frac{E}{2}, \quad \frac{E}{2}, \quad \frac{E}{2}, \quad \frac{E}{2}, \quad \frac{E}{2}, \quad \frac{E}{2}, \quad \frac{E}{2}, \quad \frac{E}{2}, \quad \frac{E}{2}, \quad \frac{E}{2}, \\ K = T + S + L_1 + L_2 + R + r + b + S + L_1 + L_2 + R + r + b + S + L_1 + L_2 + R + r + b + S + L_1 + L_2 + R + r + b + S + L_1 + L_2 + R + r + b + S + L_1 + L_2 + R + r + b + S + L_1 + L_2 + R + r + b + S + L_1 + L_2 + R + r + b + S + L_1 + L_2 + R + r + b + S + L_1 + L_2 + R + r + b + S + L_1 + L_2 + R + r + b + S + L_1 + L_2 + R + r + b + S + L_1 + L_2 + R + r + b + S + L_1 + L_2 + R + r + b + S + L_1 + L_2  BOILERS, STEAM. 211 (8.) Each line of rivets, double riveted joints. p = T × 7. for plates up to ½ inch in thickness. 6. for plates from ⅔ to ¾ inch in thickness. 5. for plates from ⅔ to ¾ inch in thickness. 4. for plates from ⅓ to ¼ inch in thickness. 4. Lap of joint. Single-riveted Double-riveted t = T × 0.5 0.5 0.35 0.35 0.25 0.25 0.15 0.15 0.1 0.1 5. Working pressure for cylindrical shells. P = T × D × t 10,000 7,000 5,000 4,000 3,000 2,500 2,000 1,500 1,250 1,125 1,000 950 900 850 800 750 700 650 600 550 500 450 400 375 350 325 312.5 300 275 262.5 250 225 212.5 200 175 162.5 156.25 148.75 142.5 137.5 132.5 127.5 122.5 117.5 112.5 107.5 102.5 97.5 92.5 87.5 82.5 77.5 72.5 67.5 62.5 57.5 52.5 47.5 42.5 37.5 32.5 27.5 22.5 17.5 12.75 11.25 9.75 8.75 7.75 6.75 6. 6. Thickness of cylindrical shell.                                                                       &nb... <img> <page_number>482</page_number> <img> Automatic Application of Brakes by Electricity.-An ingenious device has been adopted on the Northern Railway of France, by means of which brakes are applied automatically when the signals are against a train. The general principle involved is, that when the train passes a signal against  BREAD AND BISCUIT MACHINERY. 229 It, a brush of wire on the engine comes in contact with a raised wedge at the side of the rail, and closes a battery circuit. The moment this occurs the engine-whistle is sounded, and steam is turned on to the boiler, which is thus heated up to its proper temperature. This apparatus is illustrated in Fig. 485, a, which shows an engine and portion of a track fitted with the lever-gear. The lever-gear consists of two levers, A, B, and a pair of levers, C, D, which are connected by a rod, E. The levers A and B are pivoted at their upper ends to the frame of the engine, while the levers C and D are pivoted at their lower ends to the frame of the car. The levers A and B are actuated by the counterweights; F, vacuum-cylinders acted on by the ejectors and working the brake-levers; I, wires establishing the electric communication from one end of the train to the other, and connecting in series with each other all the cars in which there is an electric motor; J, a switch for opening and closing the current; K, a switch for opening and closing the current between the car and earth; L, a switch for opening and closing the current between the car and the lever; M, a switch for opening and closing the current between the lever and earth; N, a switch for opening and closing the current between the lever and earth; O, a switch for opening and closing the current between the lever and earth; P, a switch for opening and closing the current between the lever and earth; Q, a switch for opening and closing the current between the lever and earth; R, a switch for opening and closing the current between the lever and earth; S, a switch for opening and closing the current between the lever and earth; T, a switch for opening and closing the current between the lever and earth; U, a switch for opening and closing the current between the lever and earth; V, a switch for opening and closing the current between the lever and earth; W, a switch for opening and closing the current between the lever and earth; X, a switch for opening and closing the current between the lever and earth; Y, a switch for opening and closing the current between the lever and earth; Z, a switch for opening and closing the current between the lever and earth. The dotted line shows how these switches are connected together. The dotted line also shows how these switches are connected together. The dotted line also shows how these switches are connected together. The dotted line also shows how these switches are connected together. The dotted line also shows how these switches are connected together. The dotted line also shows how these switches are connected together. The dotted line also shows how these switches are connected together. The dotted line also shows how these switches are connected together. The dotted line also shows how these switches are connected together. The dotted line also shows how these switches are connected together. The dotted line also shows how these switches are connected together. The dotted line also shows how these switches are connected together. The dotted line also shows how these switches are connected together. The dotted line also shows how these switches are connected together. 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The dotted line also shows how these switches are connected together. The dotted line also shows how these switches are connected together. The dotted line also shows how these switches are connected together. The dotted line also shows how these switches are connected together. The dotted line also shows how these switches are connected together. The dotted line also shows how these switches are connected together. The dotted line also shows how these switches are connected together. The dotted line also shows how these switches are connected together. The dotted line also shows how these switches are connected together. The dotted line also shows how these switches are connected together. The dotted line also shows how these switches are connected together. The dotted line also shows how these switches are connected together. The dotted line also shows how these switches are connected together. The dotted line also shows how these switches are connected together. The dotted line also shows how these switches are connected together. The dotted line also shows how these switches are connected together. The dotted line also shows how these switches are connected together. The dotted line also shows how these switches are connected together. The dotted line also shows how these switches are connected together. The dotted line also shows how these switches areconnected  230 BREAD AND BISCUIT MACHINERY. represented in Fig. 494. The mass-mechanizer $A$ and mixer $B$ are cast in one piece, and communicate by an equilibrium-valve and raised aperture; the water-chamber $C$ is connected with a water-pipe and with the gas-generating chamber $E$, through pipes whose discharge is controlled by cocks. The flour and water are conveyed into the mass-mechanizer by means of a pipe, at a pressure of 100 lbs. per square inch, it is allowed to pass through the water, which, when thoroughly charged, is admitted to the mixing-chamber, where it is mixed with the flour and sent by revolving beater. The revolving beater is so arranged that it cannot be choked by dough. The two vessels are also connected by an equilibrium-valve $D$, allowing the dough to fall into the mixing-chamber, and then being raised up again, allowing the dough to fall into the baking-pan, $G$. When the dough is passed to the baking-pan, by means which allow of its being surrounded by air or gas under pressure, it is immediately baked in the oven, and the expansion of the dough on rising causes a slight increase in temperature. The bread rises to a height of about 15 inches above the floor of the oven; this is known as "the rise," and is due to the expansion of the gases formed during baking. The bread is baked in a steam oven, which is heated by a fire placed in a brick stove, and which is supplied with steam from a boiler. The steam is admitted to the oven by means of a pipe, and is allowed to escape through another pipe. The steam is admitted to the oven by means of a pipe, and is allowed to escape through another pipe. The steam is admitted to the oven by means of a pipe, and is allowed to escape through another pipe. The process of making baked bread is known as the "wine process," and consists in forming a paste from flour and water, which is then kneaded until it becomes soft and elastic; it is easily kneaded, requiring only half the power to work the kneading machine than would be required for hand-kneading. The dough is kneaded in a machine (shown in Fig. 495) which consists of two cylinders revolving in opposite directions, one cylinder being driven by a belt from a flywheel, while the other cylinder is driven by a belt from a motor. The dough is kneaded in this manner until the carbonic acid gas passes out of it; the dough is then allowed to rest for some time before being kneaded again. The effect of this new wine process on the flour is that the gluten cells of the starch are softened and broken up, and the dough is thus expanded more quickly than when kneaded by hand; it also becomes soft and elastic; it is easily kneaded, requiring only half the power to work the kneading machine than would be required for hand-kneading. The dough is kneaded in a machine (shown in Fig. 495) which consists of two cylinders revolving in opposite directions, one cylinder being driven by a belt from a flywheel, while the other cylinder is driven by a belt from a motor. The dough is kneaded in this manner until the carbonic acid gas passes out of it; the dough is then allowed to rest for some time before being kneaded again. The effect of this new wine process on the flour is that the gluten cells of the starch are softened and broken up, and the dough is thus expanded more quickly than when kneaded by hand; it also becomes soft and elastic; it is easily kneaded, requiring only half the power to work the kneading machine than would be required for hand-kneading. The use of such low pressures, besides being a great secondary gain, is of considerable importance in giving to the bread a soft and beautiful plastic texture. The dough, when prepared by the wine-process also makes and bakes better than the product made on an investment of 100 lbs. less than the oven-heat hitherto required for inverted bread. The effect of this new wine process on the flour is that the gluten cells of the starch are softened and broken up, and the dough is thus expanded more quickly than when kneaded by hand; it also becomes soft and elastic; it is easily kneaded, requiring only half the power to work the kneading machine than would be required for hand-kneading. Bread-making Machinery.--With Watson's bread-making apparatus (Fig. 498 to 499), the entire operation can be performed without any assistance whatever from outside persons. This apparatus has been used for many years in England, but has never been introduced into America. It consists essentially of three parts: (1) A large cylindrical mass-mechanizer (Fig. 498), which contains all necessary machinery for preparing and baking bread; (2) A large cylindrical mass-mechanizer (Fig. 498), which contains all necessary machinery for preparing and baking bread; (3) A large cylindrical mass-mechanizer (Fig. 498), which contains all necessary machinery for preparing and baking bread. 495496497498499500501502503504505506507508509510511512513514515516517518519520521522523524525526527528529530531532533233 BREAD AND BISCUIT MACHINERY. A large machine with a dough mixer at the top, a dough divider below it, and a dough sheeter below that. The rotation of the trough by the balls and dough are elevated together, and by their falling down the dough will be subjected to best handling. The dough is then taken up by the hands of the baker. Instead of employing a revolving cylinder, it is fixed; as agitator is made to revolve, and the dough is thus agitated about an axis, extending the whole length of the trough. The flour-mill or roller-making, as practised in large baking establishments in this country, consists of two parts: 1. The flour-mill or cylinder of beating; 2. mixing; 3. breaking or kneading; 4. rolling; 5. sheering; 6. cutting; 7. op- eration; the cylinder-agitator is generally used. It is raised some distance from the floor, and is supported on two shafts, one on each side, but, super, etc. It consists of a nearly cylin- drical pan U, which is supported on two shafts, which run through its centre, and is revolved by a wheel G, which is turned by a shaft H. This shaft carries four stirrers I, which are placed at right angles to the drum-former of the pan. The driving wheel G has a spur gear on its periphery, which gear into a pinion on another shaft. The pinion J drives a second wheel K, which has a toothed segment for lifting the cover and for turning it over. The cover is gener- ally 1 barrel of flour, and the time required for mixing is 10 minutes. From the mixer the dough passes into a second cylinder, of which two kinds are used, viz., the simple cylinder, and the double cylinder. In both cases only very tender dough is em- ployed, but only for very tender dough. In the simple cylinder (Fig. 489) when under the iron roller it is folded, this process is continued until the dough is perfectly smooth and elastic. The speed of this machine is about 180 revolutions per minute. Fig. 490 shows a double cylinder, the object of folding being to accomplish the same result. From the break the dough is carried to the cutting-machine, which are of various forms: 1. The V-shaped cutter; 2. The cylinder and the stamper. The latter is in more gen- eral use than the former. The cylindrical machine is much more expensive with- out any advantage whatever over the other. The stamper is made in two forms: that which requires the scraper, or the portion between the two blades of the cutter (Fig. 491), and the English machines manufactured by Vickers and others. In these machines instead of wood- en rippers, the crockers are made of metal; and an ascending apron carries the scoop into a box. A machine of the first class consists of an iron cylinder with two horizontal blades or knives which reduce the dough to about an eighth of an inch thick; these knives can be ad- justable; the cutter is in the centre of the machine; it consists of two horizontal blades un- der the cutter and over a bed-piece of hard wood, covered with rubber three-eighths of an inch thick; this bed-piece supports the cutter. The web is stretched over rollers on each end of this bed-piece; it is drawn by a toothed wheel moved by an eccentric on the cutter-shaft. The motion is such that when the A close-up view of a dough sheeter showing how it works.  BREAKER, OR CRUSHER. 233 stamper is down the wall is stationary, and as it rises it moves forward just sufficiently to bring fresh dough into place. The cutters are made of gunmetal and fixed with little ejections on both buncut and scrap. This machine is used principally for raised crackers. It makes about 100 revo- lutions per minute, and the time required varies according to the size of the loaves or other material. Bread usually requires 5 minutes; raised crackers 3 minutes; fancy crackers 2 minutes; and plain crackers 1 minute. The stamper is driven by a belt from the shaft of the flour-mill, which is connected with a gear-wheel. The movements of the aprons--of which there are three, viz., that which carries the dough direct to the cutter and the pan, the scrap elevator, so also that of the brush and presser--are regulated by a lever at the side of the machine. This motion is easily adjustable to alter the movement of the aprons and rollers. An improvement on this machine consists in placing a pair of shears between the two rollers (to whose courtesy we are indebted for the facts presented in this article), which afford a continuous feed and separate the dough from the scrap separated by a finger device, the biscuits going into pans over one. The machine makes 60 revolutions per minute, and as it rises it moves forward just suffi- ciently to bring fresh dough into place. The cutters are made of gunmetal and fixed with little ejections on both buncut and scrap. This machine is used principally for raised crackers. It makes about 100 revo- lutions per minute, and the time required varies according to the size of the loaves or other material. Bread usually requires 5 minutes; raised crackers 3 minutes; fancy crackers 2 minutes; and plain crackers 1 minute. The stamper is driven by a belt from the shaft of the flour-mill, which is connected with a gear-wheel. The movements of the aprons--of which there are three, viz., that which carries the dough direct to the cutter and the pan, the scrap elevator, so also that of the brush and presser--are regulated by a lever at the side of the machine. This motion is easily adjustable to alter the movement of the aprons and rollers. An improvement on this machine consists in placing a pair of shears between the two rollers (to whose courtesy we are indebted for the facts presented in this article), which afford a continuous feed and separate the dough from the scrap separated by a finger device, the biscuits going into pans over one. The machine makes 60 revolutions per minute, and as it rises it moves forward just suffi- ciently to bring fresh dough into place. The cutters are made of gunmetal and fixed with little ejections on both buncut and scrap. This machine is used principally for raised crackers. It makes about 100 revo- lutions per minute, and the time required varies according to the size of the loaves or other material. Bread usually requires 5 minutes; raised crackers 3 minutes; fancy crackers 2 minutes; and plain crackers 1 minute. The stamper is driven by a belt from the shaft of the flour-mill, which is connected with a gear-wheel. The movements of the aprons--of which there are three, viz., that which carries the dough direct to the cutter and the pan, the scrap elevator, so also that of the brush and presser--are regulated by a lever at the side of the machine. This motion is easily adjustable to alter the movement of the aprons and rollers. An improvement on this machine consists in placing a pair of shears between the two rollers (to whose courtesy we are indebted for the facts presented in this article), which afford a continuous feed and separate the dough from the scrap separated by a finger device, the biscuits going into pans over one. The machine makes 60 revolutions per minute, and as it rises it moves forward just suffi- ciently to bring fresh dough into place. The cutters are made of gunmetal and fixed with little ejections on both buncut and scrap. This machine is used principally for raised crackers. It makes about 100 revo- lutions per minute, and the time required varies according to the size of the loaves or other material. Bread usually requires 5 minutes; raised crackers 3 minutes; fancycrackers 2 minutes; and plain crackers 1 minute. The stamper is driven by a belt from the shaft of the flour-mill, which is connected with a gear-wheel. The movements of the aprons--of which there are three, viz., that which carries the dough direct to the cutter and the pan, the scrap elevator, so also that of the brush and presser--are regulated by a lever at the side of the machine. This motion is easily adjustable to alter the movement of the aprons and rollers. An improvement on this machine consists in placing a pair of shears between the two rollers (to whose courtesy we are indebted for the facts presented in this article), which afford a continuous feed and separate the dough from The first attempt upon the Pacific coast to substitute machine for hand labor in rolling were in the direction of stamping of unusual weight, raised by means of a height of 6 feet, and allowed to  324 BREAKER, OR CRUSHER deep upon the mass of rock to be broken. Stamps of this kind, either single or two in a battery, were placed at the superb mill erected near Aurora, at the Real del Monte, and at the Antelope. They weighed 2,000 lbs each. There were no mortars, but a solid bed or anvil was surrounded with massive pieces of iron, which were so arranged that when the stamp fell on them they would rebound back up again. The stamps were 1 foot in diameter, could be rolled in and subjected to a succession of blows. The two heads could break up almost any stone, but the smaller ones required more blows than the larger ones. We consider that for each blow a ton weight of stamp will be needed to break 4 feet, and that the smaller the mass to be broken, the greater will be the number of blows necessary. For example, if a stone 6 inches in height, lay upon the anvil, the stamp fall upon it from a height of 5 feet 6 inches; but when a block 2 feet high, which needed much harder blow, was upon the anvil, the stamp fall only from a height of 3 feet 6 inches. This is very well seen in the way in which we use at Washoe and at Virginia. At the Silver King mine on Lake Superior, heavy hammers have been used for breaking up coarse quartz gravels, and these have managed after all manner of the methods of breaking up large ore-masses. They are open- worked machines, made of pieces of native copper, which cannot be hardened by fire, but are united with ice, and in hammering are heated to redness. The Blake Breaker and Crush- er (see Fig. 498) is made by Whitney Blake of New Haven, Conn., and consists of a frame $A$ (Fig. 498), a side-view or elevation of this ma- chine being shown in Fig. 499. The bar $B$, which is fastened to the frame $A$, is called the fly-wheel shaft, which should revolve at least once per minute. The larger circle $D$, including $D_1$, is a section of the circumference $F$ of a pinion or con- vexed wheel, which is fastened to the bar $B$. The pinion $E$ is fastened to the bar $B$ by means of an al- lowe or toggle joint. If he fixed jaw, this is bolted in place, a section of its teeth, against the end of the frame. $P P'$ are circular plates against which the stone is crushed; while the lower end of the bar $B$ is fastened to the frame $A$ by means of a pin $Q Q'$. The bar $B$ is re- moved from each side, and held in place by $Q Q'$; by changing the position of the checks from right to left, whereupon they are driven into their respective holes in the bar $B$, thus holding it in place; and by moving the bar of iron $K$, which passes freely through it, and forms the piston upon which it vibrates. $L$ is a spring of iron or steel; $M M$ are bolts; $N N$ are steel tongues; $O O$ are steel tongues; $R R$ are steel tongues; $S S$ are steel tongues; $T T$ are steel tongues; $U U$ are steel tongues; $V V$ are steel tongues; $W W$ are steel tongues; $X X$ are steel tongues; $Y Y$ are steel tongues; $Z Z$ are steel tongues; $AA$ are steel tongues; $BB$ are steel tongues; $CC$ are steel tongues; $DD$ are steel tongues; $EE$ are steel tongues; $FF$ are steel tongues; $GG$ are steel tongues; $HH$ are steel tongues; $II$ are steel tongues; $JJ$ are steel tongues; $KK$ are steel tongues; $LL$ are steel tongues; $MM$ are steel tongues; $NN$ are steel tongues; $OO$ are steel tongues; $PP$ are steel tongues; $QQ$ are steel tongues; $RR$ are steel tongues; $SS$ are steel tongues; $TT$ are steel tongues; $UU$ are steel tongues; $VV$ are steel tongues; $WW$ are steel tongues; $XX$ are steel tongues; $YY$ are steel tongues; $ZZ$ are steel tongues; $AAAAA$ are steel tongues; $BBBBB$ are steel tongues; $CCCCC$ are steel tongues; $DDDDD$ are steel tongues; $EEEEEE$ are steel tongues; $FFFFF$ are steel tongues; $GGGGG$ are steel tongues; $HHHHH$ are steel tongues; $IIIII$ are steel tongues; $JJJJJ$ are steel tongues; $KKKKK$ are steel tongues; $LLLLL$ are steel tongues; $MMMMM$ are steel tongues; $NNNNN$ are steel tongues; $OOOOO$ are steel tongues; $PPPPTTQQQQQSSSSSRRRRRWWWWWXXXYYYZZZZZAAAAABBBBCCCCDDDEEEEFFFFGGGGHHHHIIIIJJKKKKLLLLMMMNNOONNOOPPPQQQQRSSSTTUUUVVWWWWWXXXXYYYYZZZZZAAAAABBBBCCCCDDDEEEEFFFFGGGGHHHHIIIIJJKKKKLLLLMMMNNOONNOOPPPQQQQRSSSTTUUUVVWWWWWXXXXYYYYZZZZZAAAAABBBBCCCCDDDEEEEFFFFGGGGHHHHIIIIJJKKKKLLLLMMMNNOONNOOPPPQQQQRSSSTTUUUVVWWWWWXXXXYYYYZZZZZAAAAABBBBCCCCDDDEEEEFFFFGGGGHHHHIIIIJJKKKKLLLLMMMNNOONNOOPPPQQQQRSSSTTUUUVVWWWWWXXXXYYYYZZZZZAAAAABBBBCCCCDDDEEEEFFFFGGGGHHHHIIIIJJKKKKLLLLMMMNNOONNOOPPPQQQQRSSSTTUUUVVWWWWWXXXXYYYYZZZZZAAAAABBBBCCCCDDDEEEEFFFFGGGGHHHHIIIIJJKKKKLLLLMMMNNOONNOOPPPQQQQRSSSTTUUUVVWWWWWXXXXYYYYZZZZZAAAAABBBBCCCCDDDEEEEFFFFGGGGHHHHIIIIJJKKKKLLLLMMMNNOONNOOPPPQQQQRSSSTTUUUVVWWWWWXXXXYYYYZZZZZAAAAABBBBCCCCDDDEEEEFFFFGGGGHHHHIIIIJJKKKKLLLLMMMNNOONNOOPPPQQQQRSSSTTUUUVVWWWWWXXXXYYYYZZZZZAAAAABBBBCCCCDDDEEEEFFFFGGGGHHHHIIIIJJKKKKLLLLMMMNNOONNOOPPPQQQQRSSSTTUUUVVWWWWWXXXXYYYYZZZZZAAAAABBBBCCCCDDDEEEEFFFFGGGGHHHHIIIIJJKKKKLLLLMMMNNOONNOOPPPQQQQRSSSTTUUUVVWWWWWXXXXYYYYZZZZZAAAAABBBBCCCCDDDEEEEFFFFGGGGHHHHIIIIJJKKKKLLLLMMMNNOONNOOPPPQQQQRSSSTTUUUVVWWWWWXXXXYYYYZZZZZAAAAABBBBCCCCDDDEEEEFFFFGGGGHHHHIIIIJJKKKKLLLLMMMNNOONNOOPPPQQQQRSSSTTUUUVVWWWWWXXXXYYYYZZZZZAAAAABBBBCCCCDDDEEEEFFFFGGGGHHHHIIIIJJKKKKLLLLMMMNNOONNOOPPPQQQQRSSSTTUUUVVWWWWWXXXXYYYYZZZZZAAAAABBBBCCCCDDDEEEEFFFFGGGGHHHHIIIIJJKKKKLLLLMMMNNOONNOOPPPQQQQRSSSTTUUUVVWWWWWXXXXYYYYZZZZZAAAAABBBBCCCCDDDEEEEFFFFGGGGHHHHIIIIJJKKKKLLLLMMMNNOONNOOPPPQQQQRSSSTTUUUVVWWWWWXXXXYYYYZZZZZAAAAABBBBCCCCDDDEEEEFFFFGGGGHHHHIIIIJJKKKKLLLLMMMNNOONNOOPPPQQQQRSSSTTUUUVVWWWWWXXXXYYYYZZZZZAAAAABBBBCCCCDDDEEEEFFFFGGGGHHHHIIIIJJKKKKLLLLMMMNNOONNOOPPPQQQQRSSSTTUUUVVWWWWWXXXXYYYYZZZZZAAAAABBBBCCCCDDDEEEEFFFFGGGGHHHHIIIIJJKKKKLLLLMMMNNOONNOOPPPQQQQRSSSTTUUUVVWWWWWXXXXYYYYZZZZZAAAAABBBBCCCCDDDEEEEFFFFGGGGHHHHIIIIJJKKKKLLLLMMMNNOONNOOPPPQQQQRSSSTTUUUVVWWWWWXXXXYYYYZZZZZAAAAABBBBCCCCDDDEEEEFFFFGGGGHHHHIIIIJJKKKKLLLLMMMNNOONNOOPPPQQQQRSSSTTUUUVVWWWWWXXXXYYYYZZZZZAAAAABBBBCCCCDDDEEEEFFFFGGGGHHHHIIIIJJKKKKLLLLMMMNNOONNOOPPPQQQQRSSSTTUUUVVWWWWWXXXXYYYYZZZZZAAAAABBBBCCCCDDDEEEEFFFFGGGGHHHHIIIIJJKKKKLLLLMMMNNOONNOOPPPQQQQRSSSTTUUUVVWWWWWXXXXYYYYZZZZZAAAAABBBBCCCCDDDEEEEFFFFGGGGHHHHIIIIJJKKKKLLLLMMMNNOONNOOPPPQQQQRSSSTTUUUVVWWWWWXXXXYYYYZZZZZAAAAABBBBCCCCDDDEEEEFFFFGGGGHHHHIIIIJJKKKKLLLLMMMNNOONNOOPPPQQQQRSSSTTUUUVVWWWWWXXXXYYYYZZZZZAAAAABBBBCCCCDDDEEEEFFFFGGGGHHHHIIIIJJKKKKLLLLMMMNNOONNOOPPPQQQQRSSSTTUUUVVWWWWWXXXXYYYYZZZZZAAAAABBBBCCCCDDDEEEEFFFFGGGGHHHHIIIIJJKKKKLLLLMMMNNOONNOOPPPQQQQRSSSTTUUUVVWWWWWXXXXYYYYZZZZZAAAAABBBBCCCCDDDEEEEFFFFGGGGHHHHIIIIJJKKKKLLLLMMMNNOONNOOPPPQQQQRSSSTTUUUVVWWWWWXXXXYYYYZZZZZAAAAABBBBCCCCDDDEEEEFFFFGGGGHHHHIIIII  BREAKER, OR CRUSHER. 235 To make good road-metal from hard compact stones, the jaws should be set from 1 to 1½ inch apart at the beginning, for softer and for granular stones it may be wider. **Holl-Breaker** is similar in principle and mode of action to the Blake machine, but differs in var- ious respects. The upper jaw is a single piece of cast iron, and is attached by means of a pin to the fixed jaw; and the jaws are driven by separate toggle-levers and eccentric, so that they make al- ternate strokes. This alternate movement is turned to account to draw back the jaws, the forward movement being assisted by a spring. The lower jaw is a single piece of cast iron, and is detachable, and is held in place by wedge-shaped bolts which may be easily tightened. The fixed jaw has the teeth on one side only, and these are arranged with respect to the movable jaw that the teeth of the latter work opposite a space in the fixed jaw, and thus give a continuous cutting action to the teeth of the movable jaw. The teeth of the each are directly opposed to the teeth of the movable jaw. The arrangement is claimed to give the jaws an improved cutting action. **Bull-Breaker** consists of an upright circular shell, in which is a vertical shaft, the upper ex- tremity of which is pivoted in a ball-and-socket bearing in the cover surrounding the shell or case. The lower extremity of this shaft is fitted with a cone-shaped roller, which revolves in its con- vex position with reference to the centre of the hub. The breaking head, which is placed near the upper end of this shaft, is also pivoted in a ball-and-socket bearing in the cover surrounding the hub; and lying in the hub of the gear below, and advances successively toward every portion of the outer wall, revolving the ore between chilker faces on both the walls and across them. The capacity of this breaker is stated to be 10,000 tons per hour. The **Bull-Breaker** is designed to work upon material on the principle of abrasion, instead of on the generally adopted principle of direct compression or impact. It breaks, crushes, and pulverizes by repeated blows against each other, and by repeated pressure against a stationary concen- trated steel faces thereof; the motion of the rubbing surfaces being obtained by the oscillation of the body. Both swing at the same time, in one and the same direction, and at an equal speed. At their different positions they strike each other with great force; and while this force (in order of production wanted) is such that the distance apart from face to face is seen as at all points of contact between them; yet they do not touch each other; but merely rub against each other's faces, and take down contact-which acts at their other extremities recovering the state that just out from their first contact; and then again striking each other with greater force than before; and move on a newly horizontal plane, alternately pushing and pulling the dice within it till the full dis- tance of the stroke, and imparting the rubbing effect. Thus, by this method, all parts of the line to dif- ferent sizes are reduced to nearly uniform size; and all kinds of steel rock. The crank-shaft drives the rolls and crank is direct by way of a pinion. The crank-shaft, fly-wheel, and pulley do not re- quire special mention. T = P × D × t × h × r² ÷ (πD²) Diameter of shell. r² ÷ (πD²) = k² × b² × c² = k² × b² × c² = k² × b² × c² = k² × b² × c² = k² × b² × c² = k² × b² × c² = k² × b² × c² = k² × b² × c² = k² × b² × c² = k² × b² × c² = k² × b² × c² = k² × b² × c² = k² × b² × c² = k² × b² × c² = k² × b² × c² = k² × b² × c² = k² × b² × c² = k² × b² × c² = k² × b² × c² = k² × b² × c² = k² × b² × c² = k² × b² × c² = k² × b² × c² = k² × b² × c² = k² × b² × c² = k² × b² × c² = k² × b² × c² = k² × b² × c² = k² × b² × c² = k² × b₂  213 BOILERS, STEAM. 11. Working pressure for stoved surface. Copper plates. Wrought-iron plates. Steel plates. $P = \frac{7T}{8} \times$ 17,000 27,000 43,000 12. Thickness for stoved surface. Copper plates. Wrought-iron plates. Steel plates. $T = S \times V^2 F$ 0.00767 0.0365858 0.0361414 13. Working pressure for stoves. $A = \frac{P}{S} \times$ Copper stays. 4,000 4,000 4,000 14. Area of stove: $d = A \times S^2 \times$ 0.00022 0.000833 15. Diameter of stove: $d = v(1.172 \times A)$, The following table for converting vulgar fractions into decimals will be found useful in connection with these rules. Nom. Fractions. Divisions. Decimals. Divisions. 1 1 1 0.995 1 1 1 0.995 1 1 1 0.995 1 1 1 0.995 1 1 1 0.995  **BOILERS.** 0.38 inch. In this example it will be seen that one of the constants has to be determined by trial, since it depends on the thickness of the plate, which is unknown. 6. The working pressure for the flat head of a cylindrical boiler, unstayed, 20 inches diameter, male of wrought-iron half as thick, $m = \frac{1}{2} \times 9000 = 22.5$ lbs. per square inch. 10. The thickness for a steel plate, unstayed, 12 inches square, exposed to a pressure of 40 lbs. per square inch, is found to be 0.075 inch. 11. The working pressure for a wrought-iron plate, stayed at intervals of 7 inches, and three-eighths of an inch thick, $= (0.75)^{\frac{3}{8}} = 27,000 = 74.5$ lbs. per square inch. 12. The thickness for a steel plate, exposed to a pressure of 100 lbs. per square inch, with stays 5 inches from centre to centre, $= \frac{5}{\sqrt{100}} = 0.0624171 = 0.34$ inch. 13. The thickness for a wrought-iron plate, unstayed, 3 inches by 3 inches, 0.65 square inch, and placed 8 inches between centres, $= \frac{8}{\sqrt{3}} = 2.84$ lbs. per square inch. 14. The area for wrought-iron stays, 8 inches between centres, for a pressure on the plate of 100 lbs. per square inch, $= 100 \times (57 - 0.0628) = 635$ square inch. 15. The perimeter of a round stay, whose area is 0.628 square inch, $y(1.725 - 0.628) = 0.89$ inch. As before remarked, if these rules are to be changed so as to give the proportions with a different degree of safety than those given in the preceding examples. Thus if a boiler is to be proportioned with only five-eighths as much strength as these rules give, multiply the constants in the for wrought-iron plates by $\frac{5}{8}$. Lifting machines are generally used in the construction of modern boilers with plates more than half an inch thick. The joints between plates are made by means of a machine called a clipping and clamping the seams. Sometimes the edges of the sheet that is to be clamped is pinned before the sheet is put into position. An important improvement in the mode of calling out the thicknesses of plates is illustrated in Fig. 448, which sufficiently shows the nature of the Where holes are cut in boilers for man and hand doors, and for connections with steam-drum, the sheet should be slightly thicker than usual, and any pipe that is attached to a boiler should be slightly thicker than usual also when being screwed into threads cut in the sheet. The method shown in Fig. 449 is secured to the tube-boshes by expanding them slightly at the inner or outer or at both edges of the sheets. Formerly this was done with a hand-tool and light hammer, but tube-expanders now employed almost exclusively. The two forms in common use are Frouss's, A diagram showing how to expand tubes. Fig. 448 and 449; and Dodson's, Fig. 449. The former, it will be seen, consists of an expanding bellow plug; in common use held together by a spring. In using this tool, it is inserted into the end of the tube, and expanded by the action of a tacker mounted driven into it; turning the expander slightly away from the tube while it is being expanded. The latter consists of a series of tubes connected by a joint which expands outwardly by the action of a tackering mandrel, which needs only to be turned a few times to do the work. It is stated that this method prevents "corrosion" or "rusting." Incrustation and Corrosion.—The action of the boiling feed water heater, which removes the solid  214 **BOILERS, STEAM.** Inquiries from the water before it enters the boiler has already been referred to. This device proves very efficacious in many instances, but there are some qualities of feed-water that cannot be purified in this manner. None of the water used in marine boilers can be rendered pure by ma- chines of this kind, because they are not adapted to deal with the large quantities of water required in creations upon the sheets and flues. The means of information on the heating surfaces of a boiler, however, have been greatly improved by the introduction of the steam-gauge, which shows at a glance the boiler temperature. In consequence of this improvement, the boiler frequently becomes overheated, and is thus rendered worthless. There are many so- called safety-valves, but none of them are really safe. They are liable to be broken by the pressure of the steam, and it is difficult to find anything that will attack incrustations, that is not also liable to injure the iron. An account of a number of these precautions, with their analysis, is contained in a "Report on Water for Marine Engines," published by the United States Department of Commerce. It is evident, however, that in the case of spring waters, as crude petroleum, soda ash, and tannate of soda. In using any of these remedies, it is necessary to heat the water thoroughly before adding it to the boiler. Otherwise it may be suffered by allowing the water to remain in the boiler after the fire is hauled, until it is quite cold, and then added to the hot water. The use of soda ash and tannate of soda have been used with some success. Tobacco juice was tried for some time in vessels of the United States Navy, and it was found that, while the amount of deposit was not diminished, it could be more easily removed. At the present time, marine-cremendors are used with nearly all marine engines and, in general, the amount of deposit is less than formerly. The reason for this is that a more perfect cleaning has been introduced into marine practice. For instance, when a con- face-container was employed, corroded very rapidly, particularly in spots over the fire, so that in a few months the crown-heat was usually taken out of place. Although the cause of this cor- rosion is not known with certainty, it appears probable that it was caused by water being carried from the cylinder into the boiler, and possibly by a slight degree of pulsation action between the brasses and cast-iron parts. When this condition existed, it was found that a very thin layer of soft lead had been deposited on the brasses. This soft lead has been removed by washing with hot water and soap solution. A similar remedy has been discovered, which consists in tinting the condenser tubes, and allowing a very thin coating of lead to form on them. This method has been found successful in several cases. As a matter of fact, it is sometimes dissolved. Mr. F. J. Rowan recommends that an artificial coating be pro- duced by feeding in a thin mixture of lead and magnesium hydroxide. In this connection it may be said that many and important improvements have been made throughout the most prominent points. For useful information on this subject, reference is made to the "Reports of the Board of Marine Inspectors," issued by the United States Department of Commerce under the direction of F. J. Rowan. **Boiler Explosions.—At present there are numerous companies that are willing, for a small premium, to insure a steam-user against loss from boiler explosions; and that succeed; but a rigid system of inspection, in preventing nearly all accidents to boilers under their charge. The boiler insurance companies have no interest whatever in promoting such an investigation into causes of explosions attending every boiler explosion occurring in that country, so that the ultimate cause of such acci- dents are unknown. The reason why explosions occur is not always due to any defect in design or construction proper; but rather the boiler, weakened in some manner, is no longer able to sustain the ordi- nary working pressure without breaking down. Such accidents are not uncommon; but they are extremely prevalent, as accepted by most intelligent engineers at present. Many of them have been directly disproved by experiments conducted by Mr. W. H. Hough (Engineering Journal, 1885; 1887; 1872); but the most remarkable one occurred in 1876 (see "The Engineer," July 30th). The following is an account thereof: [Text continues] A boiler exploded on board ship "Windsor" on June 20th last year (1885), by reason of an accident which took place during its service on board ship "Windsor." On May 20th last year (1885) this vessel left New York for Liverpool with a cargo of coal for Liverpool; she arrived at Liverpool on June 20th last year (1885). During her passage she had been subjected to considerable strain from her load; and although she had been inspected by competent engineers before leaving New York harbor (the report being dated May 1st last year), yet she had not been examined since her departure from New York harbor. On June 20th last year (1885) at about 10 o'clock p.m., while she was lying at anchor off Liverpool (England), she suddenly gave way under her own weight; and immediately after she broke up into two pieces; one piece floating on top of another piece which lay on bottom; and both pieces were floating on top of each other. The first piece floated away from ship's side about 30 feet; and then sank below water-line; and then rose again above water-line; and then sank again below water-line; and then rose again above water-line; and then sank again below water-line; and then rose again above water-line; and then sank again below water-line; and then rose again above water-line; and then sank again below water-line; and then rose again above water-line; and then sank again below water-line; and then rose again above water-line; and then sank again below water-line; and then rose again above water-line; and then sank again below water-line; and then rose again above water-line; and then sank again below water-line; and then rose again above water-line; and then sank again below water-line; and then rose again above water-line; and then sank again below water-line; and then rose again above water-line; and then sank again below water-line; and then rose again above water-line; and then sank again below water-line; and then rose again above water-line; and then sank again below water-line; and then rose again above water-line; and then sank again below water-line; and then rose again above water-line; and then sank again below water-line; and then rose again above water-line; and then sank again below water-line; and then rose again above water-line; and then sank again below water-line; and then rose again above water-line; and then sank again below water-line; and then rose again above water-line; and then sank again below water-line; and then rose again above water-line; and then sank again below water-line; and then rose again above water-line; and then sank again below water-line; and then rose again above water-line; and then sank again below水线；然后沉下水线；然后再次浮出水面；然后再次沉下水线；然后再次浮出水面；然后再次沉下水线；然后再次浮出水面；然后再次沉下水线；然后再次浮出水面；然后再次沉下水线；然后再次浮出水面；然后再次沉下水线；然后再次浮出水面；然后再次沉下水线；然后再次浮出水面；然后再次沉下水线；然后再次浮出水面；然后再次沉下水线；然后再次浮出水面；然后再次沉下水线；然后再次浮出水面；然后再次沉下水线；然后再次浮出水面；然后再次沉下水线；然后再次浮出水面；然后再次沉下水线；然后再次浮出水面；然后再次沉下水线；然后再次浮出水面；然后再次沉下水线；然后再次浮出水面；然后再次沉下水线；然后再次浮出水面；然后再次沉下水线；然后再次浮出水面；然后再次沉下水线；然后再次浮出水面；然后再次沉下水线；然后再次浮出水面；然后再次沉下水线；然后再次浮出水面；然后再次沉下水线；然后再次浮出水面；然后再次沉下水线；然后再次浮出水面；然后再次沉下水线；然后再次浮出水面；然后再次沉下水线；然后再次浮出水面；然后再次沉下水线；然后再次浮出水面；然后再次沉下水线；然后再次浮出水面；然后再次沉下水线；然后再次浮出水面；然后再次沉下水线；然后再次浮出水面；然后再次沉下水线；然后再次浮出水面；然后再次沉下水线；然后再次浮出水面；然后再次沉下水线；然后再次浮出水面；然后再次沉下水线；然后再次浮出水面；然后再次沉下水线；然后再次浮出水面；然后再次沉下水线；然后再次浮出水面；然后再次沉下水线；然后再次浮出水面；然后再次沉下水线；然后再次浮出水面；然后再次沉下水线；然后再次浮出水面；然后多次 214214  **BOILERS, SUGAR.** 215 **BOILERS, SUGAR.** See **SUGAR-MAKING MACHINERY**. **BOLESTEARS** are used to support a piece of work at a proper distance above an anvil while being punched or drilled; consequently, the greater the length of drift that protrudes beyond the work, the greater will be the force required to punch or drill it. The BOLESTEARS are made of iron, having holes of various diameters; other bolsters are slotted or may have a long narrow gap, as in forgings, to receive the work. When the work is to be drilled, it is placed on the BOLESTEARS together until the peg is of the proper width. After the bolster is finished, it is cut from the bar, which serves as a guide for the BOLESTEARS. **BOLT-MAKING MACHINERY.** See **NAIL-MAKING MACHINERY**. **BOLTS. See Mills, Gage.** **BOSE-BLACK APPARATUS.** See **SCARFING MACHINE**. **BOOK-MAKING MACHINERY.** This consists of two kinds of bookbinding, known respectively as "cloth-case" and "extra." The first is the cheapest, and that in which machinery is employed; the second is the most expensive, and that in which handwork predominates. The sheets of paper are folded at the rate of from 10,000 to 12,000 per day by folding machines (see *Book-scoring Ma- chines*). The sheets are then laid in piles, collected in sets to form the book, examined, and pressed into a neat condition by means of a press (see *Book-pressing Machines*). The book is then sewed by machinery or by hand. Several volumes are taken together, and an instant fire resulting saws make as many cuts as are necessary to separate them. The sheets are then folded into cloth cases (see *Cloth-case Making Machinery*). A late improvement in sewing sheets consists in gathering the sheets of a sheet in two hoops, old signa- tures being inserted between them. The sheets are then sewed with a machine similar to that when the sheets are gathered in proper sequence, the cuts being made by binding-tinders passing through the continuous thread formed by their interposition. This is claimed to give a very strong binding, and enables books to be sewn without difficulty. In making extra bindings, the sheets and papers are pasted on the back, and its free edge is cut in a cutting machine (see *Paper-cutting Machines*). The edges of the sheets are then trimmed with a trimming machine (see *Trimming Machines*). The case is prepared of cloth and glued, and stamped in an embossing press (see *Presses*). Finally, the book is bound with a cover of cloth or leather (see *Cloth-covering Machinery*). For the manu- facture of the hand-processes for both cloth-case and extra binding will be found in the article "Book- binding," in the *American Encyclopedia.* **BOOK-MAKING MACHINERY.** An apparatus for folding sheets of books for sewing and binding. In fig. 649 is represented a simple form of the Chambers machine. The operator transfers a sheet to his left hand and places it on a table which has been previously set up for this pur- pose. A rock-stool shaft carries a curved arm with a folder C at its extremity, which presses the table, where it passes between rollers which double it and deliver it into a sewing machine (see *Sewing Machines*). To fold an octavo, the one- folded sheet is held by its lower edge against a folding edge, when it is carried to a second roller D which turns it over, and it is thence led to a trough, where it is passed upside down. BOOT-MAKING MACHINERY. See **SHOE-MAKING MACHINERY**. **BOULDERING MACHINERY.** See **DRAILL- ING AND BORING MACHINERY**. **BOOTS:** See **PUNCHED-LEATHER**, **BLAST**, **BOTTLE-MAKING**, **Ice GLASS**, **MASONRY**, **BRACE**, **DILL**, **See DILLER**, **BREATHING MACHINE**, **BREATHING MACHINE**, (1) to a machine for separating the breath from expired air; (2) to a breathing-machine (see *Breathing Machine*), (3) to the handle of a fire-engine pump; (4) to an iron coathanger with a sharp retracting angle, used in basket-making, to fasten the bark from the oaks; (5) to a heavy machine used for rubbing muddy houses; (6) to a frame for combining refractory animals while they are alive; (7) to a machine for breaking up rocks (see *Dredging Machines*); (8) to a vehicle for breaking horses, consisting of running-gears and a driver's seat; (9) to a machine for breaking up stones; (10) to a machine for breaking up coal; (11) to break up stone by means of steam power; (12) to break up stone by means of steam power; (13) to break up stone by means of steam power; (14) to break up stone by means of steam power; (15) to break up stone by means of steam power; (16) to break up stone by means of steam power; (17) to break up stone by means of steam power; (18) to break up stone by means of steam power; (19) to break up stone by means of steam power; (20) to break up stone by means of steam power; (21) to break up stone by means of steam power; (22) to break up stone by means of steam power; (23) to break up stone by means of steam power; (24) to break up stone by means of steam power; (25) to break up stone by means of steam power; (26) to break up stone by means of steam power; (27) to break up stone by means of steam power; (28) to break up stone by means of steam power; (29) to break up stone by means of steam power; (30) to break up stone by means of steam power; (31) to break up stone by means of steam power; (32) to break up stone by means of steam power; (33) to break up stone by means of steam power; (34) to break up stone by means of steam power; (35) to break up stone by means of steam power; (36) to break up stone by means of steam power; (37) to break up stone by means of steam power; (38) to break up stone by means of steam power; (39) to break up stone by means of steam power; (40) to break up stone by means of steam power; (41) to break up stone by means of steam power; (42) to break up stone by means of steam power; (43) to break up stone by means of steam power; (44) to break up stone by means of steam power; (45) to break up stone by means of steam power; (46) to break up stone by means of steam power; (47) to break up stone by means of steam power; (48) to break up stone by means of steam power; (49) to break up stone by means of steam power; (50) to break up stone by means of steam power; (51) to break up stone by means of steam power; (52) to break up stone by means of steam power; (53) to break up stone by means of steam power; (54) to break up stone by means of steam power; 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(142)tobreakupstonebymeans-of-steam-power; (143)tobreakupstonebymeans-of-steam-power; (144)tobreakupstonebymeans-of-steam-power; (145)tobreakupstonebymeans-of-steam-power; (146)tobreakupstonebymeans-of-steam-power; (147)tobreakupstonebymeans-of-steam-power; (148)tobreakupstonebymeans-of-steam-power; (149)tobreakupstonebymeans-of-steam-power; (150)tobreakupstonebymeans-of-steam-power; (15 234567891012345678910IIIIIIIVIIIXVIIIXIXXIIXIVXVIXVIIXVIIIXIXXIIXIVXVIXVII216 **BRAKES.** automatic brakes, or, more properly speaking, some of the continuous brakes, under certain circum- stances, can be made to work automatically. In all cases the breaking force is applied to the wheels, but in the case of the hand-brakes this force is applied by means of a lever which is connected between the various brakes only in the manner in which this force is transmitted to the blocks—com- monly called action—from the motor, whether the latter be steam or air pressure, the force of grav- ity, or the weight of the train. Hard-Brakes. The ordinary hard brake is operated by a brake-man from the platform or the roof or at other convenient place on the train. It consists of two rods, one on each side of the train, and two levers. On the upper end of the rod is a hand-wheel, and to the lower end a chain in a clutch, which, when wound up by the hand-wheel, allows of a sudden release of the brake. On each side of the car, truck or car, their ends being fitted with metallic friction-blocks, which press against the wheels. The vertical rod is connected by a pin to a support on the platform or the roof of the train. The brakes are put on or released when the motion of the train is stopped. There are various other forms of hand-brakes. Screw-brakes are often used on locomotives, in which the carriage is provided with a screw which is turned by a lever. One arm of this screw is fixed to one end of a bell-crank, the other arm of the crank is pulled by a rod provided with a nut which is moved by a lever. The nut is carried simply by the weight of the brake-man, who stands at one end of a lever acting on the bars. As the effect of these brakes increases with their power, it becomes necessary for better devices to effect quick and powerful action of brakes has augmented and improved. The automatic brake was invente- red for human strength, and continuous brakes have been invented, all tending to increase safety and prevent accidents. The automatic brake is actuated by steam pressure. A fast train has depended upon whether two seconds or eighteen elapsed between the application of the brake and its complete stopping. Macdonald determined that theoretically perfect brake should stop a train running at 38 and 50 miles an hour respectively within the following distances: In bad weather. 767 feet and 1,277 feet. In moderate weather. 800 feet and 916 feet. In fine weather. 859 feet and 1000 feet. Under bad conditions. 1000 feet and 1444 feet. In order to obtain good results from the use of any form of the tender- brake, application of brakes to rear car, use of sand on rails, and reversal of engine, Captain Tyler in 1875 caused the following trials to be made on the Derby, Castle Dominion & Trust Line, Eng- land. These trials were made with three locomotives (one with steam engine) running over a line via tender-brake and one gauge's-van brake at rear of train applied, sand used, and engine reversed, and steam applied at rear car. The first trial was made with a locomotive having a weight of which was 100 tons per cwt. e.g., was running at a rate of 49.19 miles per hour when the brake was applied at rear car. The second trial was made with a locomotive having a weight of which was 100 tons per cwt. e.g., was running at a rate of 49.19 miles per hour when the brake was applied at rear car. The third trial was made with a locomotive having a weight of which was 100 tons per cwt. e.g., was running at a rate of 49.19 miles per hour when the brake was applied at rear car. The fourth trial was made with a locomotive having a weight of which was 100 tons per cwt. e.g., was running at a rate of 49.19 miles per hour when the brake was applied at rear car. The fifth trial was made with a locomotive having a weight of which was 100 tons per cwt. e.g., was running at a rate of 49.19 miles per hour when the brake was applied at rear car. The application of the brake, run a distance of 907 yards. In the second experiment all available means except reversing the engine were used; i.e., it ran up, and level; speed, 48.95 mile; time, 60 seconds; distance covered by engine alone, 352 yards; distance covered by engine plus air pressure alone, 352 yards; distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 yards; total distance covered by air pressure alone, 352 Steam-Brakes.—Those consist either of apparatus independently attached to the locomotive or to each individual truck or car or both together with an independent mechanism for operating them. An example of the first kind is a steam cylinder placed in the locomotive between the driving-wheels, with two ports communicating with cylinders in each truck or car. When steam is admitted through one port into one cylinder and out through another port into another cylinder, the piston in each cylinder moves forward and applies its force to one end of each lever connecting it with the back-end wheel or truck or car. This method is very effective but expensive because it requires two cylinders for each truck or car although they are far from being so effective as continuous brakes are. Of there are several types: I.—The first type is known as "air-pressure" brakes because it uses compressed air instead of steam. A small closed vessel which is connected with boiler through two other pipes each furnished with a cock. One cock admits steam into vessel while other admits water from sea into vessel through pipe connected with exhaust pipe. A mixture of steam and water can be introduced into closed vessel and from it hot pipe to pipe first mentioned to exhaust pipe. This provides for admission of a mixture of steam and water into vessel. The second type is known as "air-pressure" brakes because it uses compressed air instead of steam. A small closed vessel which is connected with boiler through two other pipes each furnished with a cock. One cock admits steam into vessel while other admits water from sea into vessel through pipe connected with exhaust pipe. A mixture of steam and water can be introduced into closed vessel and from it hot pipe to pipe first mentioned to exhaust pipe. This provides for admission of a mixture of steam and water into vessel. The third type is known as "air-pressure" brakes because it uses compressed air instead of steam. A small closed vessel which is connected with boiler through two other pipes each furnished with a cock. One cock admits steam into vessel while other admits water from sea into vessel through pipe connected with exhaust pipe. A mixture of steam and water can be introduced into closed vessel and from it hot pipe to pipe first mentioned to exhaust pipe. This provides for admission of a mixture of steam and water into vessel. The fourth type is known as "air-pressure" brakes because it uses compressed air instead of steam. A small closed vessel which is connected with boiler through two other pipes each furnished with a cock. One cock admits steam into vessel while other admits water from sea into vessel through pipe connected with exhaust pipe. A mixture of steam and water can be introduced into closed vessel and from it hot pipe to pipe first mentioned to exhaust pipe. This provides for admission of a mixture of steam and water into vessel. The fifth type is known as "air-pressure" brakes because it uses compressed air instead of steam. A small closed vessel which is connected with boiler through two other pipes each furnished with a cock. One cock admits steam into vessel while other admits water from sea into vessel through pipe connected with exhaust pipe. A mixture of steam and water can be introduced into closed vessel and from it hot pipe to pipe first mentioned to exhaust pipe. This provides for admission of a mixture of steam and water into vessel. The sixth type is known as "air-pressure" brakes because it uses compressed air instead of steam. A small closed vessel which is connected with boiler through two other pipes each furnished with a cock. One cock admits steam into vessel while other admits water from sea into vessel through pipe connected with exhaust pipe. A mixture of steam and water can be introduced into closed vessel and from it hot pipe to pipe first mentioned to exhaust pipe. This provides for admission of a mixture of steam and water into vessel. The seventh type is known as "air-pressure" brakes because it uses compressed air instead of steam. A small closed vessel which is connected with boiler through two other pipes each furnished with a cock. One cock admits steam into vessel while other admits water from sea into vessel through pipe connected with exhaust pipe. A mixture of steam and water can be introduced into closed vessel and from it hot pipe to pipe first mentioned to exhaust pipe. This provides for admission of a mixture of steam and water into vessel. The eighth type is known as "air-pressure" brakes because it uses compressed air instead of steam. A small closed vessel which is connected with boiler through two other pipes each furnished with a cock. One cock admits steam into vessel while other admits water from sea into vessel through pipe connected with exhaust pipe. A mixture of steam and water can be introduced into closed vessel and from it hot pipe to pipe first mentioned to exhaust pipe. This provides for admission of a mixture of steam and water into vessel. The ninth type is known as "air-pressure" brakes because it uses compressed air instead of steam. A small closed vessel which is connected with boiler through two other pipes each furnished with a cock. One cock admits steam into vessel while other admits water from sea into vessel through pipe connected with exhaust pipe. A mixture of steam and water can be introduced into closed vessel and from it hot pipe to pipe first mentioned to exhaust pipe. This provides for admission of a mixture of steam and water into vessel. The tenth type is known as "air-pressure" brakes because it uses compressed air instead of steam. A small closed vessel which is connected with boiler through two other pipes each furnished with a cock. One cock admits steam into vessel while other admits water from sea into vessel through pipe connected with exhaust pipe. A mixture of steam and water can be introduced into closed vessel and from it hot pipe to pipe first mentioned to exhaust pipe. This provides for admission of a mixture The eleventh type is known as "air-pressure" brakes because it uses compressed air instead of steam. A small closed vessel which is connected with boiler through two other pipes each furnished with a cock. One cock admits steam into vessel while other admits water from sea into vessel through pipe connected with exhaust pipe. A mixture The twelfth type is known as "air-pressure" brakes because it uses compressed The thirteenth type is known as "air-pressure" brakes because it uses compressed The fourteenth type is known as "air-pressure" brakes because it uses compressed The fifteenth type is known as "air-pressure" brakes because it uses compressed The sixteenth type is known as "air-pressure" brakes because it uses compressed The seventeenth type is known as "air-pressure" brakes because it uses compressed The eighteenth type is known as "air-pressure" brakes because it uses compressed The nineteenth type is known as "air-pressure" brakes because it uses compressed The twentieth type is known as "air-pressure" brakes because it uses compressed The twenty-first type is known as "air-pressure" brakes because it uses compressed The twenty-second type is known as "air-pressure" brakes because it uses compressed The twenty-third type is known as "air-pressure" brakes because it uses compressed The twenty-fourth type is known as "air-pressure" brakes because it uses compressed The twenty-fifth type is known as "air-pressure" brakes because it uses compressed The twenty-sixth type is known as "air-pressure" brakes because it uses compressed The twenty-seventh type is known as "air-pressure" brakes because it uses compressed The twenty-eighth type is known as "air-pressure" brakes because it uses compressed The twenty-ninth type is known as "air-pressure" brakes because it uses compressed The thirty-first type is known as "air-pressure" brakes because it uses compressed The thirty-second type is known as "air-pressure" brakes because it uses compressed The thirty-third type is known as "air-pressure" brakes because it uses compressed The thirty-fourth type is known as "air-pressure" brakes because it uses compressed The thirty-fifth type is known as "air-pressure" brakes because it uses compressed The thirty-sixth type is known as "air-pressure" brakes because it uses compressed The thirty-seventh type is known as "air-pressure" brakes because it uses compressed The thirty-eighth type is known as "air-pressure" brakes because it uses compressed The thirty-ninth type is known as "air-pressure" brakes because it uses compressed The forty-first type is known as "air-pressure" brakes because it uses compressed The forty-second type is known as "air-pressure" brakes because it uses compressed The forty-third type is known as "air-pressure" brakes because it uses compressed The forty-fourth type is known as "air-pressure" brakes because it uses compressed The forty-fifth type is known as "air-pressure" brakes because it uses compressed The forty-sixth type is known as "air-pressure" brakes because it uses compressed The forty-seventh type is known as "air-pressure" brakes because it uses compressed The forty-eighth type is known as "air-pressure" brakes because it uses compressed The forty-ninth type is known as "air-pressure" brakes because it uses compressed The fifty-first type is known as "air-pressure" brakes because it uses compressed The fifty-second type is known as "air-pressure" brakes because it uses compressed The fifty-third type is known as "air-pressure" brakes because it uses compressed The fifty-fourth type  BRAKES. 217 Lindesoe's brakes act upon the principle of producing the retarding power by using steam from the boiler as a back-pressure upon the piston in a more advantageous manner than with the reversing of the valve-gear. The steam in front of the piston is pressed back into the boiler, and acts thus by its pressure on the piston, which is connected to the brake-shaft. The steam is admitted through a simple nozzle being at the time closed, and the steam admitted through the exhaust-pipes being pumped back into the boiler. The engine is not reversed as in the Lindesoe device. Curtin's brake. The main requirements to be sought for in selecting a railway-brake which can be applied to every wheel throughout the train, if so desired, are: 1. It must be so adjustable as to allow of varying the rate of application according to circumstances. 2. It must be capable of application to every wheel throughout the train, if so desired. 3. It must be so reliable that loss of time occurs but rarely. 4. It must be so simple as to be easily understood by those who apply it, and the moment when its full power can be exerted throughout the train. 5. It must be so easy to apply by the engineer, and so simple as to enable him to put out the train. 6. It must be capable of being applied independently of other brakes and train-guards acting in concert, or by either independently of the other. 7. It must be such that all circumstances may be taken into account, and all circumstances be capable of meeting them, and that it shall be in the shortest possible distance. 8. It must be such that no accident has the effect of failing of any one of its vital parts, such fail- ure must not cause failure of the application of the brake or other- wise, so that any such failure, may be automatically arrested, and not allow any accident to de- terminate made known. 7. It must, in the event of a train breaking down, it must further be capable of immediate auto- matic application to all its wheels, under all conditions. 8. It must be so simple as to require little attention in its mode of working, and not be more expensive than required for any one of its parts than any other portion of the mechanism of the locomotive. The device is called upon to per- form two distinct functions: (1) The apparatus itself, and not by the additional weight or force which can be called in to aid its appli- cation which cannot itself fulfill the purpose for which it is used. It should preferably be incursive for free air admission and should be easily cheap in maintenance; for if the latter condition be not fulfilled, constant watching and fre- quent renewals would be required, and the eighth requirement named above would not be com- plied with. Continuous brakes may be divided into four varieties: 1. Those operating throughout the train by steam pressure only; 2. Those operated by compressed air only; 3. Those operated by electro-magnetism; 3. Those in which water is forced through pipes, which thus serves as a brake fluid; 4. Those in which compressed air is used through pipes, which thus serves as a brake fluid; 5. Those in which braking devices are operated either by compressed air or by air at normal pressure through the passages provided for each type; each variety having its own advantages and disadvantages. 1. CHAIN AND MECHANICAL BRAKES. The first class is that of the Crompton feeds. Fig. 470, may be described as follows: To the ordinary hand-wheel and brake-shafts (for winding up the brakes) is attached a chain running over a pulley on top of a cylinder, which cylinder is moved up or down by a reverse motion of the brake-shaft, to which is attached an arm and pawl; $t$, taking into consideration that this arm is hinged at $b$ and $c$, and that $d$ is a lever pivoted at $e$, $f$ being a pin which passes through $d$ and $e$. When $d$ is held in check by a lever, $a$, from $b$, the extremity of which passes a branch line to the top of the car at $D$, and continuing about 3 feet forward to the bell-coil, the branch-line is attached to A diagram showing a mechanical brake system.  218 BRAKES. here it be to such a way that when the lever is drawn up vertically, the dog disconnects. This is rendered necessary to insure the working of the brake by the bell-cord, whether the train is extended on an up grade, or contracted on a down grade. The attachment of the branch line of each car consists of a bell-cord, which is attached to the lever, and is connected with the bell-cord, either by pulling the bell-cord, and at the same time it does not interfere with the bell-cord as a means of operating the brake. The bell-cord is attached to the lever by means of a hook, and this hook is passed through a hole in the bell-cord, which is then pulled up a flat link chain, and this pulling on a set of rods under the cars causes the blocks to the wheels. By pulling on the bell-cord, and at the same time releasing the lever, the dog is released, and thus operates the brake. In case of any accident separation of the train produces this effect, namely, bringing the retarding force on all the cars into action. The *Lederberg* brake is not a true continuous brake, though, may it be fitted to every car in the track, but it is only applicable to one car at a time. The brake is applied by a lever in each car, and to one or more others in connection with it. The brakes are applied to the wheels by a friction-pulley, which engages with a friction-wheel on each side of the car. This wheel is connected with a chain running over a pulley on each side of the car, up a flat link chain, and this pulling on a set of rods under the cars causes the blocks to the wheels. By pulling on this chain, and at the same time releasing the lever, the dog is released, and thus operates the brake. In case of any accident separation of the train produces this effect, namely, bringing the retarding force on all the cars into action. The *Lederberg* brake is not a true continuous brake, though, may it be fitted to every car in the track, but it is only applicable to one car at a time. The brake is applied by a lever in each car, and to one or more others in connection with it. The brakes are applied to the wheels by a friction-pulley, which engages with a friction-wheel on each side of the car. This wheel is connected with a chain running over a pulley on each side of the car, up a flat link chain, and this pulling on a set of rods under the cars causes the blocks to the wheels. By pulling on this chain, and at the same time releasing the lever, the dog is released, and thus operates the brake. In case of any accident separation of the train produces this effect, namely, bringing the retarding force on all the cars into action. The *Lederberg* brake is not a true continuous brake, though, may it be fitted to every car in the track, but it is only applicable to one car at a time. The brake is applied by a lever in each car, and to one or more others in connection with it. The brakes are applied to the wheels by a friction-pulley, which engages with a friction-wheel on each side of the car. This wheel is connected with a chain running over a pulley on each side of the car, up a flat link chain, and this pulling on a set of rods under the cars causes the blocks to the wheels. By pulling on this chain, and at the same time releasing the lever, the dog is released, and thus operates the brake. In case of any accident separation of the train produces this effect, namely, bringing the retarding force on all the cars into action. The *Lederberg* brake is not a true continuous brake, though, may it be fitted to every car in the track, but it is only applicable to one car at a time. The brake is applied by a lever in each car, and to one or more others in connection with it. The brakes are applied to the wheels by a friction-pulley, which engages with a friction-wheel on each side of the car. This wheel is connected with a chain running over a pulley on each side of the car, up a flat link chain, and this pulling on a set of rods under the cars causes the blocks to the wheels. By pulling on this chain, and at the same time releasing the lever, the dog is released, and thus operates the brake. In case of any accident separation of the train produces this effect, namely, bringing the retarding force on all the cars into action. The *Lederberg* brake is not a true continuous brake, though, may it be fitted to every car in the track, but it is only applicable to one car at a time. The brake is applied by a lever in each car, and to one or more others in connection with it. The brakes are applied to the wheels by a friction-pulley, which engages with a friction-wheel on each side of the car. This wheel is connected with a chain running over a pulley on each side of the car, up a flat link chain, and this pulling on a set of rods under  BRAKES. 219 meatage, with a which-handle at each end, and carrying a fixed double-grooved sheave, round which in opposite directions are wound chains, two of which connect with the friction-axe. If the trans- mission-chain be tightened, a partial revolution of the sheaves is effected; and by the other chains the force of the friction-axe is communicated to the wheels of the train. In whatever direction the chain may be pulled, the action is always the same. It being important to have the work done without any slackening of the chain, this is accomplished by the constant correspon- dence for changes in the length of the train; and this was accomplished by carrying the chain from car to car, through three pulleys, R, F, G, two stationary and attached to each end of the coupland bar (which is also attached to the frame), and one movable, attached to the middle of the con- trols of the other pulleys. The three pulleys represent then the corners of a triangle with a flexible base (which is represented by the chain). The movable pulley can be moved at will over its entire length. Around these sides the chain is carried from car to car, and its length is thus con- stant, so that no slackening occurs. The chain is fastened at one end to a fixed point on the car, and placed at any point of the train, or in several places, pulleys on the chain to means of a crank or a hand-wheel, and put the brakes on. To this end, after the train has been made up and the ordinary coupling between cars has been effected, all that remains to do is to bring together the ends of the chains until the friction-rings are brought into contact with the wheels; the transmission-couplings are then fast- ened. The brake is then applied by pulling on one of the handles; and this is done by means of a ratchet wheel, passing by means of a lever from one side of the chain to another, as shown in Fig. 471. The junction of the chains is shown at such a point, that with the maximum motion of the chain, either by tightening up or slackening out, it cannot pass over either of the pulleys. The union of these chains is effected by means of a spring which holds them together when they are in position; but when they are separated, they are held apart by springs connected with their respective ends. When an application or taking off of the brakes is said to be instantaneously applied or taken off, it means that immediately after it has been applied or taken off, it is instantly applied or taken off again. This operation is performed by means of a lever which is attached to both ends of each chain; and when it is desired to apply or take off brakes on more parts, the separated parts would immediately be automatically acted upon by the brake. Another ad- vantage which this brake possesses over many other common brakes is that its action begins without any slackening of the chain; and therefore it does not require any time for its effectuation. A further claim that by this brake any train at the highest speed can be brought to a standstill in all weather is also claimed. 2. ELECTRO-MAGNETIC BRAKE.—Austrian's Brake (Fischel).—Each carriage of the train is supplied with a powerful electromagnet which attracts a steel plate attached to each wheel. The electromagnet is placed with the engine foot-plate, by means of four insulated wires passing through whole length of train. By means of these wires two distinct currents may be sent through either wire or wires at once or both separately. The current sent through one wire attracts one plate; while that sent through another wire attracts another plate above forward axle, upon one end which is fixed a strong steel plate; while that sent through another wire attracts another plate below forward axle, upon one end which is fixed a strong steel plate; while that sent through another wire attracts another plate below rear axle, upon one end which is fixed a strong steel plate; while that sent through another wire attracts another plate below rear axle, upon one end which is fixed a strong steel plate; while that sent through another wire attracts another plate below rear axle, upon one end which is fixed a strong steel plate; while that sent through another wire attracts another plate below rear axle, upon one end which is fixed a strong steel plate; while that sent through another wire attracts another plate below rear axle, upon one end which is fixed a strong steel plate; while that sent through another wire attracts another plate below rear axle, upon one end which is fixed a strong steel plate; while that sent through another wire attracts another plate below rear axle, upon one end which is fixed a strong steel plate; while that sent through another wire attracts another plate below rear axle, upon one end which is fixed a strong steel plate; while that sent through another wire attracts another plate below rear axle, upon one end which is fixed a strong steel plate; while that sent through another wire attracts another plate below rear axle, upon one end which is fixed a strong steel plate; while that sent through another wire attracts another plate below rear axle, upon one end which is fixed a strong steel plate; while that sent through another wire attracts another plate below rear axle, upon one end which is fixed a strong steel plate; while that sent through another wire attracts another plate below rear axle, upon one end which is fixed a strong steel plate; while that sent through another wire attracts another plate below rear axle, upon one end which is fixed a strong steel plate; while that sent through another wire attracts another plate below rear axle, upon one end which is fixed a strong steel plate; while that sent through another wire attracts another plate below rear axle, upon one end which is fixed a strong steel plate; while that sent through another wire attracts another plate below rear axle, upon one end which is fixed a strong steel plate; while that sent through another wire attracts another plate below rear axle, upon one end which is fixed a strong steel plate; while that sent through another wire attracts another plate below rear axle, upon one end which is fixed a strong steel plate; while that sent through another wire attracts another plate below rear axle, upon one end which is fixed a strong steel plate; while that sent through another wire attracts another plate below rear axle, upon one end which is fixed a strong steel plate; while that sent through another wire attracts another plate below rear axle, upon one end which is fixed a strong steel plate; while that sent through another wire attracts another plate below rear axle, upon one end which is fixed a strong steel plate; while that sent through another wire attracts another plate below rear axle, upon one end which is fixed a strong steel plate; while that sent through another wire attracts another plate below rear axle, upon one end which is fixed a strong steel plate; while that sent through another wire attracts another plate below rear axle, upon one end which is fixed a strong steel plate; while that sent through another wire attracts another plate below rear axle, upon one end which is fixed a strong steel plate; while that sent through another wire attracts another plate below rear axle, upon one end which is fixed a strong steel plate; while that sent through another wire attracts another plate below rear axle, upon one end which is fixed a strong steel plate; while that sent through another wire attracts another plate below rear axle, upon one end which is fixed a strong steel plate; while that sent through another wire attracts another plate below rear axle, upon one end which is fixed a strong steel plate; while that sent through another wire attracts another plate below rear axle, upon one end which is fixed a strong steel plate; while that sent through another wire attracts another plate below rear axle, upon one end which is fixed a strong steel plate; while that sent through another wire attracts another plate below rear axle, upon one end which is fixed a strong steel plate; while that sent through another wire attracts another plate below rear axle, upon one end which is fixed a strong steel plate; while that sent through another wire attracts another plate below rear axle, upon one end which is fixed a strong steel plate; while that sent through another wire attracts another plate below rear axe  220 **BRAKES** filled with water and running from the tender underneath all the cars of the train. The water is first conveyed from the tender-tank to a 8-way cock, which is placed on the locomotive, where it is always kept full. From this cock, three pipes run into the engine, one under the boiler, another below the water-line; a third pipe leads from the same cock and runs under the cars, the connections between each car being made by means of a coupling. The fourth pipe is connected with the brake-cylinder of each car, a case-rail cylinder, the rod of which is connected to the brake-lever. The pipe at each end of the train has an air-cock, to allow the air to escape while the pipe is being filled with water. When the water is drawn up, the air-cock is closed, and when the pipe is running under the cars it is kept open, thus keeping the pipes and brake-cylinders constantly full of water. This arrangement prevents any air from entering into the cylinders, and also keeps the communication between the tender and pipes under the cars. This cock is so constructed that the connection can be opened or closed without removing it from its place. The pressure of power is from acting on the water in the tank. To relieve the pressure and to take off the brake, the engineer simply turns the lever back to its original position, and the brakes are instantly off, the service being resumed by turning the lever forward again. The *Henderson* Hydraulic Brake (American), Fig. 473.—Between the wheels of each truck is placed a cylinder, which is connected with a piston, and this piston communicates with a chamber by means of a plunger. The plunger is connected with a lever, which in turn operates a brake-cylinder. The power of the plunger is communicated to it by means of a double-acting steam-pump. In order to obtain power from acting on the water in the tank, a valve must be inserted in line with this pump. In the annexed engraving, Fig. 474, the brake-shoes are arranged outside the wheels, and hence one of the cylinders and rams is depressed with, $u$ = 0. It is double-acting pressure-equipment. $U$ = 0 when there is no pressure on either side of the diaphragm. The steam used in operating these brakes comes from a separate boiler, and passes through a valve from the boiler if not employed. Clow's *Steam* Brake (English).—The brakes are actuated by one cylinder under each carriage. The water under pressure is supplied as follows: Under the footplate of the engine is a vertical cylinder fitted with a piston and plunger. A second cylinder is placed horizontally beneath this vertical cylinder is fitted a steel piston, and to this horizontal cylinder a plunger, which actuates the brakes on the engine-wheel. The cylinders between the piston and plunger are filled with water, $u$ = 0 when there is no pressure on either side of the diaphragm. The steam passes through a valve into both cylinders, but only one of them at a time; this causes a slight leakage. To apply the brakes steam is admitted under the piston in the vertical cylinder; and thus piston moves outwards and pushes against a spring which holds it in place until sufficient supply of water under pressure to the pipes, and thus applies the brakes. A diagram showing how it may be achieved through operation through a vacuum and those oper- ated by compressed air. **Fleming's Steam Brake (English)** differs materially from others of this kind inasmuch as instead of a vacuum being applied to operate the brake, it is made use of to operate the brake-shoes out of contact with the wheels. In other words, the brakes in their normal condition are $u$ = 0 when there is no pressure on either side of diaphragm. The steam passes through two passages exerted upon diaphragms, from one side of which it has been partially exhausted. The passage leading to one side of diaphragm contains an exhaust valve which opens during operation of train, connected between these passages by flexible pipes and couplings, and an exhausted drum under each carriage, by which the brakes are released when the train is in motion. The pipe and apparatus shown in dotted lines lead to a reservoir containing water which supplies steam to each cylinder when steam is now used as "a blowers" before entering chimney of locomotive. When this happens steam enters cylinder and expands causing piston to move outwards; this man in motion requires exhausting action is effected by a small pump worked from one of piston cases-hose. **Smith's Vacuum-Brake**.—In this device both levers are applied to one side of each wheel by col- lapsing of India-rubber cylindrical bags, which are supported by internal rings so that when air is absorbed by these bags they contract and pull on levers; thus applying brakes to train. There extend two lines of pipe; some hoses being connected to one line while other extends right through to rear end where it is connected to its mentioned line by closing-up of diaphragm. A diagram showing how Fleming's Steam Brake operates.  BRAKES. 221 one hose-pipe on the last vehicle. The exhaustion of the air from the pipe is effected partly by a supply of steam ejectors on the engine, and partly by exhaustion fixed in each break-ax, and driven by a wire rope, which passes over a grooved pulley, cast in one piece with a friction-guiler, which acts as a brake upon the wheel. The other end of this wire rope is attached to a double friction-pulley, which is fixed against the axle-pulley by means of a spring, but when the train is running, the rope is slackened by the weight of the car. The two ends of the wire rope are connected with the collapsing bag with which each car is fitted. The effect of this arrangement is that, immediately after the breaking of the brake-lever, from the ejector of the engine being set at work, it increases the trigger, and thus brings the friction-guiler into action. The Waterhouse Vacuum-Brake.—In this system the vacuum is produced by an ejector which is connected to the atmosphere through a pipe, and also to a reservoir, communicating with the annular opening $A$ and the central joint $F$, $P$, $Q$, which creates an im- pression between them. The exhaust-pipe $D$ communicates with two pipes $D$, which are connected with the brake-pipes. Under each car are two independent flexible cylinders, connected by the bellows $E$. When the valve is opened, both bellows are filled with air. There- fore, the atmospheric pressure is exerted on the outside to compress the cylin- ders from collapsing sideways, so that the atmospheric pressure is applied to both sides of the piston, and the other is attached to the brake-levers, so that whatever pressure is exerted on the brake-lever is communicated to the brake-levers, and thus causes them to move. When the valve is closed, both bellows do not contain any air, so used a cylinder is placed vertically, and at each side of it is attached a lever. This lever is called a trigger-lever. At its upper point, a toggle-lever. The two toggle-levers have curved abutting sur- faces, so that when they are pressed together they are held in contact with each other attached to the piston. The effect is that, as the piston rises on the air being exhausted from the bellows, both toggle-levers are forced outward. To the lower ends of the hanging levers are coupled the thrust-cords leading to the brake-levers. As soon as these cords are pulled outwards by their movement, the upward movement of the piston The Waterhouse Automatic Brake.— The Waterhouse automatic brake, in its original form, consisted of a pump connected to a reservoir under which was placed a piston. This pump forced air at any required density into a reservoir usually placed underneath the foot-board of the engine. Each car was provided with a pipe connecting it with this reservoir. A second pipe was con- nected with the brake-levers, and the air-pressure communicated with the bellows of each car through another pipe placed between each car. When it was desired to apply the brakes, the non- operating cars were disconnected from their respective pumps by turning a cock so that the supply of compressed air stored up in the former would flow into the cylinder, and would then force out the air contained therein. In order to prevent this action from occurring, there was some apparatus necessary to allow sufficient quantity of air to flow through each car's pipe into its respective bellows before any pressure was imposed with the number of cars, because not only was the length of pipes through which the compressed air had to pass increased, but also the number of cylinders and, of course, the pressure of air was increased in like proportion. There was also another difficulty encountered. In case of the breaking of a connection in a train, all cars were stopped simultaneously. This was due to an error in design, upon which no attention has been paid since. The cause was that when one end of the train connected to the engine, and thus arrest its speed. As an consequence of this slip-operation being repeated many times during one journey, all cars were stopped at once. The speed of those which had broken loose by means of atmospheric brake. Accidents sometimes occurred owing to this cause. In the automatic brake construction is simplified, and but one line of pipe is used. The com- pressing apparatus consists of a steam-cylinder $A$ and pump $J$, Fig. 475., is bolted to the boiler or tunnel wall near its front end. The steam enters through a valve $B$, which can be turned either way, being regulated by its throttle, while the exhaust is led by a pipe to one or more smoke-chutes. The air from these chutes passes through a pipe $C$ into another valve $D$, which opens into one end of a long pipe $E$. This pipe leads to one opening of the three-way cock $F$, and from a second opening, is extended be- hind each car's foot-board until it reaches its rear end. A third opening leads from this pipe to another valve $G$, from which an un- valve movement is used, in which the difference in area between the two ends is such that, when cars are admitted between them, the tendency of the valve is to move upward, which gives a down- ward movement to those cars behind it. Thus when one car breaks away from its connection with upon reversing valve operation causing valve $E$ to uncover a port by which steam is admitted into another pipe $H$, which leads directly into another valve $I$. From this valve steam flows from the upper part of the steam-cylinder, and admitting steam below main piston. As the main piston comes down it closes off this passage and as an exhaust steam from this The working cylinder whereby reversing operation is moved upwards together with main valve $I$, by the difference of pressure between two valves pistons. A diagram showing various components of an automatic braking system.  223 **BRAKES.** Figs. 477 and 478 show the application of the automatic brake to an ordinary 8-wheeled car. Fig. 477 is an inverted plan, and Fig. 478 an end-view. The brake-cylinder $d$, which is to be seen in plan, is fixed and securely fastened to the longitudinal tim- ber and attached to the car frame. The piston of this cylinder has a cross-head $a$, having an arm $b$, to which the spring releasing lever $c$ is connected. To this cross-head $a$ is attached one end of the lever $d$, the opposite end of which is connected to the other end of the lever $f$. The other end of the lever $d$, opposite the cross-head $a$, is a bracket $g$, which acts as a fulcrum for one end of this lever $f$, the other end of which is also pinned to another brake-coupling; the levers $d$ and $f$ are connected by a tie- A diagram showing the arrangement of the automatic brake on a car. rod $g$. These levers are so arranged that if the piston be thrust forward, carrying the cross-head $a$, the two rods $b$ will approach each other, and thus apply the brakes. The levers $d$ and $f$ are held in an horizontal position by the bracket $A$ (a portion of which is represented as broken away in Fig. 477), made up of two pieces, one being fixed to the car frame, and the other to the car body. They are ar- ranged near the centre of the car transversely as is convenient, and the stoppows are near each end of the car. The auxiliary reservoir $R$ is also attached by iron straps to the bottom of the car frame, and is connected with the brake-cylinder by a pipe. As soon as the action of the brake be at a very great extent dependent upon the working of the triple and leakage valves, it becomes evident that such a device must be highly efficient. It will be under- stand clearly the action of this ingenious and beautiful contrivance. Fig. 479 represents a section of the triple valve, and Fig. 480 a section of the leakage valve. A diagram showing a section of a triple valve. A diagram showing a section of a leakage valve.  BRAKES. 223 The triple valve has a case, or body, with three connections for half-inch pipe-jets, the connection from the main pipe being through the port $F$; a second pipe-connection from the port $F$ leads to the brake-cylinder, while the remaining port, shown in dotted lines back of the valve $V$, is connected to the auxiliary reservoir. This case contains the body of the triple-valve, and water-chamber, $A$, and has also a piston-chamber, or cylinder, $B$, which is kept open by a spring, $C$, and communicates with the chambers by the end of the upper end of the case. The cover $D$, screwed into the upper end of the case, is a slide-valve, which is held in position between a shoulder and collar on the cover $D$, and moves with it. In the chamber $B$ under this slide-valve are two ports or passages, 5 and $d$; the first, passing through the plug of the four-way cock, $17$, connects with the port $F$, and thence to the brake-cylinder. A diagram showing a triple-valve mechanism. Google In the chamber $B$ under this slide-valve are two ports or passages, 5 and $d$; the first, passing through the plug of the four-way cock, $17$, connects with the port $F$, and thence to the brake-cylinder. A diagram showing a triple-valve mechanism. Google In the chamber $B$ under this slide-valve are two ports or passages, 5 and $d$; the first, passing through the plug of the four-way cock, $17$, connects with the port $F$, and thence to the brake-cylinder. A diagram showing a triple-valve mechanism. Google In the chamber $B$ under this slide-valve are two ports or passages, 5 and $d$; the first, passing through the plug of the four-way cock, $17$, connects with the port $F$, and thence to the brake-cylinder. A diagram showing a triple-valve mechanism. Google In the chamber $B$ under this slide-valve are two ports or passages, 5 and $d$; the first, passing through the plug of the four-way cock, $17$, connects with the port $F$, and thence to the brake-cylinder. A diagram showing a triple-valve mechanism. Google In the chamber $B$ under this slide-valve are two ports or passages, 5 and $d$; the first, passing through the plug of the four-way cock, $17$, connects with the port $F$, and thence to the brake-cylinder. A diagram showing a triple-valve mechanism. Google In the chamber $B$ under this slide-valve are two ports or passages, 5 and $d$; the first, passing through the plug of the four-way cock, $17$, connects with the port $F$, and thence to the brake-cylinder. A diagram showing a triple-valve mechanism. Google In the chamber $B$ under this slide-valve are two ports or passages, 5 and $d$; the first, passing through the plug of the four-way cock, $17$, connects with the port $F$, and thence to the brake-cylinder. A diagram showing a triple-valve mechanism. Google In the chamber $B$ under this slide-valve are two ports or passages, 5 and $d$; the first, passing through the plug of the four-way cock, $17$, connects with the port $F$, and thence to the brake-cylinder. A diagram showing a triple-valve mechanism. Google In the chamber $B$ under this slide-valve are two ports or passages, 5 and $d$; the first, passing through the plug of the four-way cock, $17$, connects with the port $F$, and thence to the brake-cylinder. A diagram showing a triple-valve mechanism. Google In the chamber $B$ under this slide-valve are two ports or passages, 5 and $d$; the first, passing through the plug of the four-way cock, $17$, connects with the port $F$, and thence to the brake-cylinder. A diagram showing a triple-valve mechanism. Google In the chamber $B$ under this slide-valve are two ports or passages, 5 and $d$; the first, passing through the plug of the four-way cock, $17$, connects with the port $F$, and thence to the brake-cylinder. A diagram showing a triple-valve mechanism. Google In the chamber $B$ under this slide-valve are two ports or passages, 5 and $d$; the first, passing through the plug of the four-way cock, $17$, connects with the port $F$, and thence to the brake-cylinder. A diagram showing a triple-valve mechanism. Google In the chamber $B$ under this slide-valve are two ports or passages, 5 and $d$; the first, passing through the plug of the four-way cock, $17$, connects with the port $F$, and thence to the brake-cylinder. A diagram showing a triple-valve mechanism. Google In the chamber $B$ under this slide-valve are two ports or passages, 5 and $d$; the first, passing through the plug of the four-way cock, $17$, connects with The spring $\alpha_0$ is used for recharging purposes. To recharge air into The spring $\alpha_0$ is used for recharging purposes. To recharge air into The spring $\alpha_0$ is used for recharging purposes. To recharge air into The spring $\alpha_0$ is used for recharging purposes. To recharge air into The spring $\alpha_0$ is used for recharging purposes. To recharge air into The spring $\alpha_0$ is used for recharging purposes. To recharge air into The spring $\alpha_0$ is used for recharging purposes. To recharge air into The spring $\alpha_0$ is used for recharging purposes. To recharge air into The spring $\alpha_0$ is used for recharging purposes. To recharge air into The spring $\alpha_0$ is used for recharging purposes. To recharge air into The spring $\alpha_0$ is used for recharging purposes. 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This valve consists of a case, 18, with a cap, 19, having a rubber face, 16, and within the chamber of this case a valve, 14, which is acted upon by air-pressure entering the lower port. When the air enters through the upper port of the cylinder, it forces the piston, 15, to move against the rubber face 16, preventing the escape of air. A spring, $H_1$, is screwed on the cap $P$ of the triple-valve-pump, $H_2$, and when this spring is compressed by the admission of air into the pump, before the ports $A$ and $F$ in connection, whereby the air passes directly from the brake-pipe to the brake-cylinder for the direct application of the brake, without charging any of the other parts. Both these valves are shown in their open position in Figs. 481 and 482. In the operation of the brakes, the couplings between the cars are connected in usual man-ner, and the handle of all three cocks in the main brake-pipes are turned down so as to open them, excepting that one cock is left closed for the purpose of admitting atmospheric air into the pipe. When it is necessary to detail any portion of the train, the cocks must first be closed to prevent the escape of air and the application of the brakes. Each reservoir contains a stop-valve, which may be opened to release the brakes if they should be applied accidentally when the pipe is disconnected from the main reservoir. A branch leads to a valve located in the water-closet in the car, and the handle of this valve has a cord-attachment which passes through the interior of the car. If this valve be opened by an em-ployee or passenger who desires to use water from his cistern, he can do so without thus being applied to the whole train. The escape from this valve is led through the bottom of the car. Figs. 481 and 482 represent the application of an atmospheric brake to the driving-wheels of a locomotive. The brake is applied to the driving-wheels by means of a cylinder, $H$. The piston-end $K$ of the cylinder is connected with a rod which is attached to a lever (Fig. 483), which in turn is attached to the brake-blocks $L$. When compressed air is admitted underneath the piston in the cylinder $H$, it is obvious that its action on the cams $13$, $15$ will force the brake-blocks against the wheel. The Steel and Ironman Brake.—This is applied under two different arrangements: that in which the cylinders are placed at each end of each car (Fig. 484) and that in which they are placed at each end and that in which the cylinder is placed at centre of each carriage, in which case one cylinder is placed at each end and another at centre (Fig. 485). The latter arrangement employs steam-engine and air-pumps. When the air is let out through pipes from the reservoirs it enters the upper end of each cylinder and expands through a valve in such as to A diagram showing a detailed view of a braking system. 485  BRAKES. 225 metre. Instantly, then, the pressure per square inch of area on both sides of the piston is in equilibrium, but by virtue of the weight of the train, the piston being greater than that of the car side, by a quantity represented by the area of a cross-section of the piston-rod, the pressure on the upper side of the piston is increased, and this pressure is communicated to the brake-gear, immediately causing the piston to descend to the bottom of the cylinders, in which position the brakes are off. The air is kept constantly on, and to apply the brakes it is only necessary to open one or more valves, which admit air into the cylinders, and thus force the piston down upon the assen- ger, in either of which case the air escapes from the upper sides of the piston, and that on the lower side is forced up through the connecting-pipe, and so into the atmosphere, thereby immediately expelling, lifts the pistons and applies the brakes. As the air-pipe is connected with both ends of the brake and air-couplers to take off. The apparatus is thus in principle similar to the Wootlhouse, with the exception of the spring. The normal condition of the train is such that all the brakes applied by the action of the springs. If the engine be put in motion, and at once apply a brake to one or more wheels, these will be thrown clear of the rails, leaving them free to move; but pressure is kept upon the pipes, and so long as this is done the brakes may be applied without any danger to the train. When a brake is applied to one or more wheels of the car, which are connected to the air-couplers by half-hitch pipes. These are coupled together between the cars by flexible hose. The annular cogging represents the form of this brake en- gine as used in America. It has been found that many improvements have been made in connexion with this work, is engaged upon important improvements, calculated to add materially to the efficiency of this apparatus. The following table gives some data relative to its application. The indispensable requirement of a power-brake are an automatic governing power of the force, be it drawn what it may; namely, a means of regulating and controlling its operation; also a means of applying sufficient pressure to hold back all other forces which might tend to throw out of balance or upset the train. In order to accomplish this purpose, it is necessary to utilize the maximum adhesion of the train in emergencies, and never slide wheels, the lighter degrees of force for other purposes to be regulated by the throttle or cock ; to vary this degree according to circumstances; also to regulate and control all other parts of this apparatus; such as pipes and cylinders; to insure several breakings before the air is reduced to a minimum pressure; so that it can be applied when required; also to prevent any undue pressure being applied to any part of this apparatus; and finally, to guard against over-pressure in any part of this apparatus, and to prevent any undue pressure being applied. Towels of Brakes.--The following, explaining a simple rule for determining theoretically the resistance offered by a train moving at different velocities on level ground under various conditions, is taken from "Annual Report of the Railway Master-Engineers' Association" for 1876: "Let us suppose that a train consisting of an engine weighing 10 tons, with a tender weighing 20 tons, and 10 passenger-coaches each weighing 3 tons, will travel at 20 miles per hour on a straight level track. It is required to know the distance in which said train will stop after applying the brakes, which are assumed to be fitted to the tender and six cars. A speed of 40 miles per hour will require a stopping distance equal to 100 yards; at 50 miles per hour it will be approximately half as much; with an initial velocity of that amount, will exceed 55 feet before it is arrested by the force of gravity. Similarly a railway-train moving on an horizontal track at the same speed will be stopped in about 100 yards; but if it be going at 60 miles per hour it will require nearly double its own weight in stopping distance." The resistance of the atmosphere is not taken into account in either case as pre- 15  226 BRAKES. TABLE OF APPLICATION ON CUSTOMER BRAKES. BRAKE APPLICABLE TO NOT APPLICABLE TO 1. Single Wheel Single Wheel Double Wheel 2. Double Wheel Double Wheel Single Wheel 3. Single Wheel with Hub Cover Single Wheel with Hub Cover Double Wheel with Hub Cover 4. Double Wheel with Hub Cover Double Wheel with Hub Cover Single Wheel with Hub Cover 5. Single Wheel with Hub Cover and Spoke Guard Single Wheel with Hub Cover and Spoke Guard Double Wheel with Hub Cover and Spoke Guard 6. Double Wheel with Hub Cover and Spoke Guard Double Wheel with Hub Cover and Spoke Guard Single Wheel with Hub Cover and Spoke Guard 7. Single Wheel with Hub Cover, Spoke Guard and Rim Guard Single Wheel with Hub Cover, Spoke Guard and Rim Guard Double Wheel with Hub Cover, Spoke Guard and Rim Guard 8. Double Wheel with Hub Cover, Spoke Guard and Rim Guard Double Wheel with Hub Cover, Spoke Guard and Rim Guard Single Wheel with Hub Cover, Spoke Guard and Rim Guard 9. Single Wheel with Hub Cover, Spoke Guard, Rim Guard and Tire Support Bar Single Wheel with Hub Cover, Spoke Guard, Rim Guard and Tire Support Bar Double Wheel with Hub Cover, Spoke Guard, Rim Guard and Tire Support Bar 10. Double Wheel with Hub Cover, Spoke Guard, Rim Guard and Tire Support Bar Double Wheel with Hub Cover, Spoke Guard, Rim Guard and Tire Support Bar Single Wheel with Hub Cover, Spoke Guard, Rim Guard and Tire Support Bar 11. Single Wheel with Hub Cover, Spoke Guard, Rim Guard and Tire Support Bar on Both Sides of the Carriage (for use on both sides) Single Wheel with Hub Cover, Spoke Guard, Rim Guard and Tire Support Bar on Both Sides of the Carriage (for use on both sides) Double Wheel with Hub Cover, Spoke Guard, Rim Guard and Tire Support Bar on Both Sides of the Carriage (for use on both sides) 12. Double Wheel with Hub Cover, Spoke Guard, Rim Guard and Tire Support Bar on Both Sides of the Carriage (for use on both sides) Double Wheel with Hub Cover, Spoke Guard, Rim Guard and Tire Support Bar on Both Sides of the Carriage (for use on both sides) Single Wheel with Hub Cover, Spoke Guard, Rim Guard and Tire Support Bar on Both Sides of the Carriage (for use on both sides) NOTE: LUGS ARE NOT RECOMMENDED FOR USE WITH THESE BRAKES. A table showing various brake applications for different types of wheels. 226 Google  BRAKES. 227 m. Now, the resisting forces available for stopping a train are the friction of the brakes upon the wheels, the axle-friction, the rolling friction of the wheels upon the track, and the resistive ance of the atmosphere. The brake-friction bears a certain proportion to the pressure applied, and some allowance must be made for this. The resistance of the atmosphere may also be considered as a fair average allowance. The pressure upon the brakes is limited by the weight on the wheels, which is usually 30 tons per foot of length. The resistance of the wheels upon the brakes and axle and rolling friction to prevent sliding of the wheels. If we allow one ton for speed and axle friction, to be on the safe side (it is actually less than half that amount), it will be 15 tons per foot of length. The resistance of the atmosphere is about 10 tons per foot of length, so that the brake resistance, including all these factors, will be 25 tons per foot of length. This will be the brake resistance. To this must add the axle and rolling friction, and the resistance of the smoothness of the track. The total resistance will then be 48,713 lbs., or one-seventh of the weight of the train. If we assume that the braking force is equal to its own weight, it will run seven times that distance, or 374 feet at the starting force is one-seventh of that amount, and will consume about 13 seconds of time. But this is only a rough estimate. It does not take into account any other factor, such as the greatest of shutting off, which is never the case in practice. With the original Westinghouse brake, three fourths of the power was used in stopping a train. With this brake, if we assume that it will be safe to assume that a distance of 160 feet will be passed over before the full effect of the brake has been obtained, and that it takes 13 seconds to stop a train running at 20 miles per hour, then it will take 13 seconds to stop a train running at 160 miles per hour. In practice, however, a train runs after shutting off and applying the brake will be 304 feet, and the time required may be roughly summed as 16 seconds. The table below shows the results of experiments on continuous brakes made on the Midland Railway, England, June, 1876. The tests marked A were on stopping trains by tender and van brakes only; B were on trains with both tender and van brakes; C were on trains with only van brakes; D were on trains with only tender brakes; E were on trains with both tender and van brakes; F were on trains with only van brakes; G were on trains with both tender and van brakes; H were on trains with only van brakes; I were on trains with both tender and van brakes; J were on trains with both tender and van brakes; K were on trains with both tender and van brakes; L were on trains with both tender and van brakes; M were on trains with both tender and van brakes; N were on trains with both tender and van brakes; O were on trains with both tender and van brakes; P were on trains with both tender and van brakes; Q were on trains with both tender and van brakes; R were on trains with both tender and van brakes; S were on trains with both tender and van brakes; T were on trains with both tender and van brakes; U were on trains with both tender and van brakes; V were on trains with both tender and van brakes; W were on trains with both tender and van brakes; X were on trains with both tender and van brakes; Y were on trains with both tender and van brakes; Z were on trains with both tender and van brakes. Experiments E were on stopping trains on a signal given to the rear guard, or at some inter- mediate point on the train, the driver being signalled to apply brakes. The expectation is that driver would apply his brake when he saw signal given to rear guard. But this is not true in practice because of the fact that the signal was given at the rear of the train, but differ in the driver taking active no action until he saw signal given to rear guard. In order to test this point, experiments E were applied. Experiments G were on stopping trains by use of the engine and tender brakes only, the engine being required to stop at a point where it could not stop without applying its own brake. When running a by a pull coupling, continuous brake then being required to effectively control two parts of the patent system. In the year 1876, which is confined from that prepared by Engineering vol. xii., experi- ments which failed wholly or partially are omitted. Descriptions of the brakes will be found dis- cussed in later chapters. A competitive trial opened in January, 1877, between the Westinghouse vacuum and the Smith vacuum brake systems. The Smith vacuum brake was tested at speeds varying from 20 miles per hour up to 80 miles per hour; number of seconds occupied in making stop: Smith: 28; Westinghouse: 21. Num- ber of feet occupied in making stop: Smith: 1372; Westinghouse: 104. At a speed of 75 miles per hour, number of seconds occupied in making stop: Smith: 25; Westinghouse: 20. Number of feet occupied in making stop: Smith: 1538 seconds and 490 feet. Total weight of train load fitted with Smith vacuum brake: 45 tons. Total weight of train load fitted with Westinghouse vacuum brake: 45 tons. and fitted with Westinghouse brake: 60 tons 10 cwt.; portion locked: 60% per cent. of total The Longbridge Air-Brake.—This brake, constructed as shown in the engraving on a proceeding page, was tested in February, 1878, on the Baltimore & Ohio Railroad, with the following result:— Number of seconds occupied in making stop: 25 seconds. Number of feet occupied in making stop: Speed of train when brakes were applied: 42.61 miles per hour; time occupied in making stop: 16 sec- onds under normal conditions. Time occupied in making stop: Speed of train when brakes were applied: Under normal conditions. Time occupied in making stop: Speed of train when brakes were applied: Under normal conditions. Time occupied in making stop: Speed of train when brakes were applied: Under normal conditions. Time occupied in making stop: Speed of train when brakes were applied: Under normal conditions. Time occupied in making stop: Speed of train when brakes were applied: Under normal conditions. Time occupied in making stop: Speed of train when brakes were applied: Under normal conditions. Time occupied in making stop: Speed of train when brakes were applied: Under normal conditions. Time occupied in making stop: Speed of train when brakes were applied: Under normal conditions. Time occupied in making stop: Speed of train when brakes were applied: Under normal conditions. Time occupied in making stop: Speed of train when brakes were applied: Under normal conditions. Time occupied in making stop: Speed of train when brakes were applied: Under normal conditions. Time occupied in making stop: Speed of train when brakes were applied: Under normal conditions. Time occupied in making stop: Speed of train when brakes were applied: Under normal conditions. Time occupied in making stop: Speed of train when brakes were applied: Under normal conditions. Time occupied in making stop: Speed of train when brakes were applied: Under normal conditions. Time occupied in making stop: Speed of train when brakes were applied: Under normal conditions. Time occupied in making stop: Speed of train when brakes were applied: Under normal conditions. Time occupied in making stop: Speed of train when brakes were applied: Under normal conditions. Time occupied in making stop: Speed of train when brakes were applied: Under normal conditions. Time occupied in making stop: Speed of train when brakes were applied: Under normal conditions. Time occupied in making stop: Speed of train when brakes were applied: Under normal conditions. Time occupied in making stop: Speed of train when brakes were applied: Under normal conditions. Time occupied in making stop: Speed of train when brakes were applied: Under normal conditions. Time occupied in making stop: Speed of train when brakes were applied: Under normal conditions. Time occupied in making stop: Speed of train when brakes were applied: Under normal conditions. Time occupied in making stop: Speed of train when brakes were applied: Under normal conditions. Time occupied in making stop: Speed of train when brakes were applied: Under normal conditions. Time occupied in making stop: Speed of train when brakes were applied: Under normal conditions. Time occupied in making stop: Speed of train when brakes were applied: Under normal conditions. Time occupied in making stop: Speed of train when brakes were applied: Under normal conditions. Time occupied in making stop: Speed of train when brakes were applied: Under normal conditions. Time occupied in making stop: Speed of train when brakes were applied: Under normal conditions. Time occupied in making stop: Speed of train when brakes were applied: Under normal conditions. Time occupied in making stop: Speed of train when brakes were applied: Under normal conditions. Time occupied in making stop: Speed of train when brakes were applied: Under normal conditions. Time occupied in making stop: Speed of train when brakes were applied: Under normal conditions. Time occupied in making stop: (1) Train stopped on same grade, 80 miles per hour, in 22 seconds and 970 feet. Steam-gauge pressure, (2) Train stopped on down-grade over 30 feet, 80 miles per hour, in 1 second and 900 feet. Steam-gauge pressure, (3) Train stopped on down-grade over 30 feet, 80 miles per hour, in 1 second and 900 feet. Steam-gauge pressure, (4) Train stopped on down-grade over 30 feet, 80 miles per hour, in 1 second and 900 feet. Steam-gauge pressure, (5) Train stopped on down-grade over 30 feet, 80 miles per hour, in 1 second and 900 feet. Steam-gauge pressure, (6) Train stopped on down-grade over 30 feet, 80 miles per hour, in 1 second and 900 feet. Steam-gauge pressure, (7) Train stopped on down-grade over 30 feet, 80 miles per hour, in 1 second and 900 feet. Steam-gauge pressure, (8) Train stopped on down-grade over 30 feet, 80 miles per hour, in 1 second and 900 feet. Steam-gauge pressure, (9) Train stopped on down-grade over 30 feet, 80 miles per hour, in 1 second and 900 feet. Steam-gauge pressure, (10) Train stopped on down-grade over  BRAKES. Table of Results, corrected for Speed, Friction of Train's Gravity, and Under Brake Block Press- ure, Trains meeting of Engine braked on the Driving-Wheels, Tender braked on all Wheels, Four Carriages braked and Two unbraked. Speed. Power on Brakes-Blocks Distance from Point of Percentage Reduction of Diametem. Weighting Heated. Test. Total. Miles per Hour. which the Brakes are applied Braked Portion of Train. 45.0 30 17.38 17.38 17.38 17.38 17.38 55.0 30 95.06 17.35 17.35 17.35 17.35 65.0 30 60.04 17.34 17.34 17.34 17.34 75.0 30 60.02 17.34 17.34 No result. No result.                                                                   No result.<br> NUMBER. Distance of Rollers. Weight. Capacity of roll. P. P. required. 16 8 25000 150 15 to 16 16 8 25000 150 15 to 16 16 8 25000 150 15 to 16 16 8 25000 150 15 to 16 16 8 25000 150 15 to 16 16 8 25000 150 15 to 16 16 8 25000 150 hand power. Total. Capacity (tons). Roller Diameter (inches). Number of Rollers. Roller Weight (pounds). Power Required (horsepower). Roller Speed (revolutions per minute). Roller Speed (feet per second). Roller Speed (feet per second). Roller Speed (feet per second). Roller Speed (feet per second). Roller Speed (feet per second). Roller Speed (feet per second). Roller Speed (feet per second). Roller Speed (feet per second). Roller Speed (feet per second). Roller Speed (feet per second). Roller Speed (feet per second). Roller Speed (feet per second). Roller Speed (feet per second). Roller Speed (feet per second). Roller Speed (feet per second). Roller Speed (feet per second). Roller Speed (feet per second). Roller Speed (feet per second). Roller Speed (feet per second). Roller Speed (feet per second). Roller Speed (feet per second). Roller Speed (feet per second). Roller Speed (feet per second). Roller Speed (feet per second). Roller Speed (feet per second). Roller Speed (feet per second). Roller Speed (feet per second). Roller Speed (feet per second). Roller Speed (feet per second). Roller Speed (feet per second). Roller Speed (feet per second). Roller Speed (feet per second). Roller Speed (feet per second). Roller Speed (feet per second). Roller Speed (feet per second). Roller Speed (feet per second). Roller Speed (feet per second). Roller Speed (feet per second). Roller Speed (feet per second). Roller Speed (feet per second). | NUMBER | Distance of Rollers | Weight | Capacity | P.P. required | |--------|---------------------|-------|----------|--------------| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A diagram showing a bull-breaker mechanism.236 BREAKER, OR CRUSHER them, would break the machine; and moreover, they would not crush as fast and well without a certain amount of yielding to the materials carried through between them. The use of rubber springs offers a method of giving the necessary resistance, which increases with the degree of separation of the material. The rubber spring is made in such a way that the product of its action against the material is greater than when one is carried around merely by the friction of the steel spring. It is also usual to have three or more rolls where the crushing takes place, and these are placed close to rolling each other so that their surfaces may act upon each other. In this case, the force on the surface of the rollers upon the masses, they are made solid. The fragments falling from this first pair of rolls are then passed into another pair of rolls, and so on. The number of pairs of rolls used in the crushing rolls varies from 14 to 34 inches (27 inches is a common diameter), and the length or breadth of the rolls varies from 10 to 18 inches. The diameter of the rolls is usually from 14 to 24 inches, but they are very large, having 34 inches diameter and 22 inches face, and a pressing force on the rolls of 458 tons, reviving 700 tons are in common use for dressings. The average time required for crushing one ton of coal in 10 hours at a cost of 22 per cent. ton. At present, most rolls are in common use for dressings, but there are some exceptions from the jigg- ing process—in which, for instance, galls are intermixed with blonde or gauze, and which, as a rule, are crushed in two pairs of rolls. In the course rolls, which work under very heavy pressure of from 20 to 30 tons counterweights, it is advisable to use a single pair of rolls. This is because the pressure on the counterweights is generally smaller than that on the main roll. The pressure on the counterweight is therefore less likely to cause any damage to the main roll. In the Rhineland ores—especially those containing a considerable amount of clay—the pressure on the main roll must be increased to about 100 tons. From 50 to 60 tons of rolling stuff, varying as the gauze mixed with the ore is silicious or calcareous, and from 50 to 60 tons of dressing stuff, varying as the gauze mixed with the dressing stuff is silicious or calcareous, and from 50 to 60 tons of dressing stuff, varying as the gauze mixed with the dressing stuff is silicious or calcareous, and from 50 to 60 tons of dressing stuff, varying as the gauze mixed with the dressing stuff is silicious or calcareous, and from 50 to 60 tons of dressing stuff, varying as the gauze mixed with the dressing stuff is silicious or calcareous, and from 50 to 60 tons of dressing stuff, varying as the gauze mixed with the dressing stuff is silicious or calcareous, and from 50 to 60 tons of dressing stuff, varying as the gauze mixed with the dressing stuff is silicious or calcareous, and from 50 to 60 tons of dressing stuff, varying as the gauze mixed with the dressing stuff is silicious or calcareous, and from 50 to 60 tons of dressing stuff, varying as the gauze mixed with the dressing stuff is silicious or calcareous, and from 50 to 60 tons of dressing stuff, varying as the gauze mixed with the dressing stuff is silicious or calcareous, and from 50 to 60 tons of dressing stuff, varying as the gauze mixed with the dressing stuff is silicious or calcareous, and from 50 to 60 tons of dressing stuff, varying as the gauze mixed with the dressing stuff is silicious or calcareous, and from 50 to 60 tons of dressing stuff, varying as the gauze mixed with the dressing stuff is silicious or calcareous, and from 50 to 60 tons of dressing stuff, varying as the gauze mixed with the dressing stuff is silicious or calcareous, and from 50 to 60 tons of dressing stuff, varying as the gauze mixed with the dressing stuff is silicious or calcareous, and from 50 to 60 tons of dressing stuff, varying as the gauze mixed with the dressing stuff is silicious or calcareous, and from 50 to 60 tons of dressing stuff, varying as the gauze mixed with the dressing stuff is silicious or calcareous, and from 50 to 60 tons of dressing stuff, varying as the gauze mixed with the dressing stuff is silicious or calcareous, and from 50 to 60 tons of dressing stuff, varying as the gauze mixed with the dressing stuff is silicious or calcareous, and from 50 to 60 tons of dressing stuff, varying as the gauze mixed with the dressing stuff is silicious or calcareous, and from 50 to 60 tons of dressing stuff, varying as the gauze mixed with the dressing stuff is silicious or calcareous, and from 50 to 60 tons of dressing stuff, varying as the gauze mixed with the dressing stuff is silicious or calcareous, and from 50 to 60 tons of dressing stuff, varying as the gauze mixed with the dressing stuff is silicious or calcareous, and from 50 to 60 tons of dressing stuff, varying as the gauze mixed with the dressing stuff is silicious or calcareous, and from 50 to 60 tons of dressing stuff, varying as the gauze mixed with the dressing stuff is silicious or calcareous, and from 50 to 60 tons of dressing stuff, varying as the gauze mixed with the dressing stuff is silicious or calcareous, and from 50 to 60 tons of dressing stuff, varying as the gauze mixed with the dressing stuff is silicious or calcareous, and from 50 to 60 tons of dressing stuff, varying as the gauze mixed with the dressing stuff is silicious or calcareous, and from 50 to 60 tons of dressing stuff, varying as the gauze mixed with the dressing stuff is silicious or calcareous, and from 50 to 60 tons of dressing stuff, varying as the gauze mixed with the dressing stuff is silicious or calcareous, and from 50 to 60 tons of dressing stuff, varying as the gauze mixed with the dressing stuff is silicious or calcareous, and from 50 to 60 tons of dressing stuff, varying as the gauze mixed with the dressing stuff is silicious or calcareous, and from 50 to 60 tons of dressing stuff, varying as the gauze mixed with the dressing stuff is silicious or calcareous, The use of rubber springs offers a method of giving resistance which increases with degree separation of material. The rubber spring made in such a way that product action against material greater than when one carried around merely by friction steel spring. It usual have three more rolls where crushing takes place these are placed close together so that their surfaces may act upon each other. In this case force on surface rollers upon masses they made solid. Fragments falling first pair these rolls then passed into another pair these rolls length breadth rolls varies from inches diameter inches length breadth rolls varies inches diameter inches length breadth rolls varies inches diameter inches length breadth rolls varies inches diameter inches length breadth rolls varies inches diameter inches length breadth rolls varies inches diameter inches length breadth rolls varies inches diameter inches length breadth rolls varies inches diameter inches length breadth rolls varies inches diameter inches length breadth rolls varies inches diameter inches length breadth rolls varies inches diameter inches length breadth rolls varies inches diameter inches length breadth rolls varies inches diameter inches length breadth rolls varies inches diameter inches length breadth rolls varies inches diameter inches length breadth rolls varies inches diameter inches length breadth rolls varies inches diameter inches length breadth rolls varies inches diameter inches length breadth rolls varies inches diameter inches length breadth rolls varies inches diameter inches length breadth rolls varies inches diameter inches length breadth rolls varies inches diameter inches length breadth rolls varies inches diameter inches length breadth rolls varies inches diameter inches length breadth rolls varies inches diameter inches length breadth rolls varies inches diameter inches length breadth rolls varies inches diameter inches length breadth rolls varies inches diameter inches length breadth rolls varies inches diameter inches length breadth rolls varies inches diameter inches length breadth rolls varies inches diameter inches length breadth rolls varies inches diameter inches length breadth rolls varies inches diameter inches length breadth rolls varies inches diameter inches length breadth rolls varies inches diameter inches length breadth rolls varies inches diameter inches length breadth rolls varies inches diameter inches length breadth rolls varies 237238239241242243244245247248249251252253254255257258259261263264267271273274277278281283284287289291293294297311A black-and-white illustration showing a diagrammatic view of a coal-breaking machine.A black-and-white illustration showing a diagrammatic view of a coal-breaking machine.A black-and-white illustration showing a diagrammatic view of a coal-breaking machine.A black-and-white illustration showing a diagrammatic view of a coal-breaking machine.A black-and-white illustration showing a diagrammatic view of a coal-breaking machine.A black-and-white illustration showing a diagrammatic view of a coal-breaking machine.A black-and-white illustration showing a diagrammatic view of a coal-breaking machine.A black-and-white illustration showing a diagrammatic view of a coal-breaking machine.A black-and-white illustration showing a diagrammatic view of a coal-breaking machine.A black-and-white illustration showing a diagrammatic view of a coal-breaking machine.A black-and-white illustration showing a diagrammatic view of a coal-breaking machine.A black-and-white illustration showing a diagrammatic view of a coal-breaking machine.A black-and-white illustration showing a diagrammatic view of a coal-breaking machine.A black-and-white illustration showing a diagrammatic view of a coal-breaking machine.A black-and-white illustration showing a diagrammatic view of a coal-breaking machine.A black-and-white illustration showing a diagrammatic view of a coal-breaking machine.A black-and-white illustration showing a diagrammatic view of a coal-breaking machine.A black-and-white illustration showing a diagrammatic view of a coal-breaking machine.A black-and-white illustration showing a diagrammatic view of a coal-breaking machine.A black-and-white illustration showing a diagrammatic view of a coal-breaking machine.A black-and-white illustration showing a diagrammatic view of a coal-breaking machine.A black-and-white illustration showing a diagrammatic view of a coal-breaking machine.A black-and-white illustration showing a diagrammatic view of a coal-breaking machine.A black-and-white illustration showing a diagrammatic view of a coal-breaking machine.A black-and-white illustration showing a diagrammatic view of a coal-breaking machine.A black-and-white illustration showing a diagrammatic view of a coal-breaking machine. A black-and-white illustration showing a coal-breaking machine. A black-and-white illustration showing a coal-breaking machine. A black-and-white illustration showing a coal-breaking machine. A black-and-white illustration showing a coal-breaking machine. A black-and-white illustration showing a coal-breaking machine. A black-and-white illustration showing a coal-breaking machine. A black-and-white illustration showing a coal-breaking machine. A black-and-white illustration showing a coal-breaking machine. A black-and-white illustration showing a coal-breaking machine. A black-and-white illustration showing a coal-breaking machine. A black-and-white illustration showing a coal-breaking machine. A black-and-white illustration showing a coal-breaking machine. A black-and-white illustration showing a coal-breaking machine. A black-and-white illustration showing a coal-breaking machine. A black-and-white illustration showing a coal-breaking machine. A black-and-white illustration showing a coal-breaking machine. A black-and-white illustration showing a coal-breaking machine. A black-and-white illustration showing a coal-breaking machine. A black-and-white illustration showing a coal-breaking machine. A black-and-white illustration showing a coal-breaking machine. A black-and-white illustration showing a coal-breaking machine. A black-and-white illustration showing a coal-breaking machine. A black-and-white illustration showing a coal-breaking machine. A black-and-white illustration showing a coal-breaking machine. A black-and-white illustration showing a coal-breaking machine. A black-and-white illustration showing a coal-breaking machine. A black-and-white illustration showing A black and white illustration showing a diagrammatic view of a coal- breaking machine. A black and white illustration showing a diagrammatic view of a coal- breaking machine. A black and white illustration showing a diagrammatic view of a coal- breaking machine. A black and white illustration showing a diagrammatic view of a coal- breaking machine. A black and white illustration showing a diagrammatic view of a coal- breaking machine. A black and  BREAKWATER. 237 used equally by means of a motion common to both. If such a break-water glass way, the roll, with bearings set free, can revolve without obstruction, while the other bearing turns on its cylindrical part. By means of this arrangement, which works in a similar manner to the ball-joint journals, as A diagram showing a mechanism for breaking waves. The main components include a central shaft (A), two side arms (B), and a series of rollers (C) that rotate around the central shaft. The rollers are connected to the side arms, which are fixed to the shore. The side arms are designed to move up and down, allowing the rollers to clear the water.Box of Shipping Journal smooth a revolution as possible of the axis is produced with diminished friction and wear, notwithstanding the great weight of the rolling mass. In Germany, rolls which are provided with sharp projecting ribs are used in the crushing mills of coal-washing establishments. To prevent the interfering of these ribs, they are wound round the cylinder of the mill with a band of leather or cloth, so as to keep them at a distance from each other; but even for such coal-washing establishments the improved American method rolls with narrow ribs have been found superior to those of Ores and Coal," by E. F. Alden, in "Reports of Judges of Group I, Centennial Exposition." BREAKWATER. A kind of artificial embankment, ditch, or rampart, formed of large stones and earth, and intended to protect a harbor from the force of the sea and its effects by the action of the visi- 14 lent winds, by breaking the force of the waves of the sea; the shipping moored behind it lying protected from all danger from the sea. The first break-water was constructed at Plymouth, Portsmouth, and Blythhead in England, and Delaware Bay in this country. The experience obtained in building these breakwaters has shown that they are only effective when subjected to their greatest violence, establish the principle that blocks of stone of large dimensions only can be depended upon to retain their places. Mr. James Walker, President of the British Institution of  238 BREAKWATER Civil Engineers advanced the opinion in 1841 that a partial vacuum is created by the action of the waves, and that the atmospheric pressure being taken off for an instant, the mass of stone is the more readily removed by the force of the water. This was first pointed out by M. de la Connerie (in Baudouin, 1841). If the whole atmospheric pressure were taken off the surface, it would be equivalent to the removal of a layer of water equal to one inch. The depth of water at which this occurs is called the cube foot. Under such circumstances, and exposed to the action of a wave 30 feet high, which is capable of moving masses of rock 70 feet deep, stability would be insured only by the addition of an amount of stone equal to one cubic foot. Best Form of Breakwater—from the fact that any settlement of the foundation is far more perilous in a vertical than in a horizontal wall, and that the latter can be constructed with less difficulty than the former, it follows that the ordinary method of forming the low-water parts of deep harbours with large masses of rubble-stone or concrete blocks, is in most circumstances, the best and cheapest kind of construction when a vertical wall is in use. When a vertical block wall is built upon a soft bottom, or upon a bed of sand, stones, etc., they are liable to sink in or to be underwhelmed, then when a vertical wall is founded upon a soft bottom. Loose concrete blocks are liable to sink into a soft foundation, and to be broken up by the waves. For these reasons, should, however, he kept in view, first, the wall should be founded at a sufficiently low level to prevent any portion of it from being submerged by the highest tides; secondly, that it should be so constructed as not to act as a breakwater and not as a pier, there should be no parapet, the absence of which reduces the force of the waves striking against it; thirdly, that it should be so placed as to secure from loading wide foreshore at the bottom or top of the slope. Thus, however, many local peculiarities in selecting the best design for any work, and the nature of the bottom is in all cases important. The Cherbourg Breakwater was begun in 1853. The building of this wall was commenced upon applied contract. The height of its top above mean high water was 60 feet; its base was 60 feet at the top, and about 60 or 70 feet high, the depth of water at spring tide, in the line in which they were originally laid. The stone was laid on a bed of mortar; after each course was laid and after allowing some time for settling, the masonry was intended to be commenced upon them. But a few of these courses only were completed, when, in consequence of the difficulty of the undertaking, it was found necessary to construct a pier between two points where this way is intended also as a military construction, for the protection of the roadstead against an enemy's fleet. The cross-section shown in Fig. 495 was adopted for its Frosting by experience of many years. Observation. It was decided to construct the form that forms the cannon-battery of solid masonry laid on a thick and broad bed of boulders. The top surface of the breakwater is covered with heavy loose blocks. The lower part consists entirely of massive blocks laid on a bed of mortar formed from boulders. The experience acquired at this work has conclusively shown that breakwaters formed on the horizontal blocks of stone are liable either to damage in heavy gales when the sea breaks over them or else to be undermined by waves during storms. In order to avoid both these defects a system was adopted in which massive blocks are laid on a bed of mortar and then covered with loose blocks resting on a bed of mortar. The whole structure is thus made up entirely from stone and mortar. The wall is 60 feet high above mean high water and 120 feet long at its base above highest water. This is protected by a foreshore of great blocks of stone A on the outer side which extend in a slope from 1:1 to 1:2 at their base and 1:2 at their top; on the inner side there is a similar foreshore (the slope of its sides being 1:1) at 8 feet 8 inches wide at base and 9 feet 8 inches wide at top. The altitude of the breakwater is 72.5 feet, and the base of its sea-side measures 228 feet. Its length is nearly 1000 yards. The cost per yard was £35. The total cost including land with its opening towards land. The work was completed in 1854, and its total cost is stated to have been £13,650. The Plymouth Breakwater, Figs. 496 and 497, commenced in 1852. It is composed of blocks of stone from 1 to 2 tons in weight, and extends from central part 1500 yards long and two Plan of Plymouth Breakwater. wings each 350 yards long, directed towards sea, and forming angles of 18° with centre-poin- tions. A transverse section taken through the breakwater shows an average base of 390 feet, and  BREAKWATER 239 NAME Period General Layout of Outer Work Inner Work Dredging Other Dredging Total Dredging Free Board to Low Tide Level Wall Depth Dredge Depth Freeboard Freeboard Freeboard Freeboard Freeboard Freeboard Freeboard Freeboard Freeboard Pylons: Pylons with concrete base and concrete cap. 10 to 1 3 to 4 3 to 4 3 to 4 3 to 4 3 to 4 3 to 4 3 to 4 3 to 4 3 to 4 3 to 4 3 to 4 Pylons with concrete base and steel cap. 10 to 1 3 to 4 3 to 4 3 to 4 3 to 4 3 to 4 3 to 4 3 to 4 3 to 4 3 to 4 3 to 4 3 to 4 Pylons with concrete base and steel cap (continued). 10 to 1 3 to 4 3 to 4 3 to 4 3 to 4 3 to 4 3 to 4 3 to 4 3 to 4 3 to 4 3 to 4 3 to 4 < BREAKWATER 239 NAME' ' Period' ' ' '

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