Syringes continued to be used in London till the latter part of the 17th century, when they were superseded by more improved machines. They were usually made of brass and held from two to four quarts. The smaller ones were about two feet and a half long, and an inch and a half in diameter; the bore of the nozzles being half an inch. Three men were required to work each, which they achieved in this manner: one man on each side, grasped the cylinder with one hand and the nozzle with the other; while the third man worked the piston! Those who held the instrument plunged the nozzle into a vessel of water, the operator then drew back the piston and thus charged the cylinder, and when it was raised by the bearers into the required position, he pushed in the piston and forced, or rather endeavored to force, the contents upon the fire.[A]
Fig. 392.
Figs. [390] and [391] show an early form of syringe. A description of it translated from the original Greek, written by Hero of the ancient city of Alexandria, reads thus—“A hollow tube of some length is made, A, B; into this another tube, C, D, is nicely fitted, to the extremity of which is fastened a small plate or piston; at, D, is a handle, E, F. Cover the orifice, A, of the tube, A, B, with a plate in which an extremely fine tube, G, H, is fixed, its bore communicating with A, B, through the plate—as a vacuum is thus produced in A, B, something else must enter to fill it, and as there is no other passage but through the mouth of the small tube we shall of necessity draw up through this any fluid that may be near.”
[A] Note.—We are told that some of these syringes are preserved in one or two of the parish churches. It can excite no surprise that London should have been almost wholly destroyed in the great fire of 1666, when such were the machines upon which the inhabitants chiefly depended for protecting their property and dwellings. If the diminutive size of these instruments be considered, the number of hands required to work each, beside others to carry water and vessels for them, the difficulty and often impossibility of approaching sufficiently near so as to reach the flames with the jet, the loss of part of the stream at the beginning and end of each stroke of the piston, and the trifling effect produced—the whole act of using them, appears rather as a farce. These primitive devices were known as “hand squirts.”
Fig. [392] is a copy of an old engraving (A. D. 1568) which shows an “engine” of this type sufficiently enlarged to contain a barrel or more of water and as a matter of necessity, placed on a carriage.
Fig. 393.
To eject the water uniformly, the inventor moved the piston by a screw; and when the cylinder was emptied, it was refilled through the funnel by an attendant, as the piston was drawn back by reversing the motion of the crank. When recharged, the stop cock in the pipe of the funnel was closed and the liquid forced out as before. As flexible pipes of leather, the “ball and socket” and “goose-neck” joints had not been introduced, some mode of changing the direction of the jet of this enormous syringe was necessary. To effect this, it is represented as suspended on pivots, fastened in two upright posts: to these are secured (see [figure]) two semi-circular straps of iron, whose centers coincide with the axis, or pivots, on which the syringe is balanced. A number of holes are made in each, and are so arranged as to be opposite each other. A bolt is passed through two of these, and also through a similar hole, in a piece of metal, that is firmly secured to the upper part of the open end of the cylinder; and thus holds the latter in any required position. The iron frame to which the box or female part of the screw is attached, is made fast to the cylinder; and it is through a projecting piece on the end of this frame that the bolt is passed. By these means, any elevation could be given to the nozzle, and the syringe could be secured by passing the bolt through the piece just mentioned, and through the corresponding holes in the straps. When a lateral change in the jet was required, the whole machine was moved by a man at the end of the pole, as in the figure. Jointed feet were attached to the frame which were let down when the engine was at work.
Fig. [393] shows an engine for extinguishing fires, which has come down to us from the times of Hero, who thus describes it: