Note.—The siphons used in conflagrations are made as follows. Take two vessels of bronze, A B C D, E F G H (Fig. [393]), having the inner surface bored in a lathe to fit a piston (like the barrels of water-organs), K L, M N, being the pistons fitted to the boxes. Let the cylinders communicate with each other by means of the tube, X O D F, and be provided with valves, P, R, such as have been explained above, within the tube, X O D F, and opening outwards from the cylinders. In the bases of the cylinders pierce circular apertures, S, T, covered with polished hemispherical cups, V Q, W Y, through which insert spindles soldered to, or in some way connected with, the bases of the cylinders, and provided with shoulders at the extremities that the cups may not be forced off the spindles. To the center of the pistons fasten the vertical rods, S E, S E, and attach to these the beam A´ A´, working, at its center, about the stationary pin, D, and about the pins, B, C, at the rods, S E, S E. Let the vertical tube, S´ E´, communicate with the tube, X O D F, branching into two arms at, S´, and provided with small pipes through which to force up water, such as were explained above in the description of the machine for producing a water-jet by means of the compressed air.
Now, if the cylinders, provided with these additions be plunged into a vessel containing water, I J U Z, and the beam, A´ A´, be made to work at its extremities, A´, A´, which move alternately about the pin, D, the pistons, as they descend, will drive out the water through the tube, E´ S, and the revolving mouth, M´. For when the piston, M N, ascends it opens the aperture, T, as the cup, W Y, rises, and shuts the valve, R; but when it descends it shuts, T, and opens, R, through which the water is driven and forced upwards. The action of the other piston, K L, is the same. Now the small pipe, M´, which waves backward and forward, ejects the water to the required height but not in the required direction, unless the whole machine be turned round; which on urgent occasions is a tedious and difficult process. In order therefore, that the water may be ejected to the spot required, let the tube, E´ S´, consist of two tubes, fitting closely together lengthwise, of which one must be attached to the tube, X O D F, and the other to the part from which the arms branch off at, S´; and thus, if the upper tube be turned round, by the inclination of the mouthpiece, M´, the stream of water can be forced to any spot we please. The upper joint of the double tube must be secured to the lower to prevent its being forced from the machine by the violence of the water. This may be effected by holdfasts in the shape of the letter L, soldered to the upper tube, and sliding on a ring which encircles the lower.
Fig. 394.
(See page [109].)
Heron or Hero was an Alexandrian mathematician of the 3d Century B. C. He was the inventor of “Hero’s Fountain” in which a jet of water was maintained by condensed air and of a machine acting upon the principle of Barker’s Mill, in which the motion was produced by steam. Fragments of his works on mechanics have been preserved for more than 2000 years.
Lack of space forbids following, as could be done, the growth of the modern steam fire engine from these primitive beginnings to its present high point of excellence and widely extended use. Wherever civilized men are gathered into towns and cities there can be found this admirable mechanism affording protection to both life and property.
The Working Parts,
The Boiler, and
Its facilities for Transportation are the three essential parts of the one mechanism which combined, form the steam fire engine. In brief reference to the last qualification, it may be said that these engines are drawn by hand, by one or more horses, or other animals and are self-propelled by both steam and electric power; again the hose carriage can be drawn by hand, by horses or can be attached to the engine.
The main working parts of the machine can be easily divided into two parts, the engine and the pump.