“The face of the disk is ground smooth, so as to fit close to the under side of the plate, against which it is pressed by the steam. The perpendicular axle by which the disk is turned passes through the plate, and the opening is made tight by a stuffing-box. (The plate and movable disk are represented in the small figure at the top, one of the openings, Q, being covered by the disk and the other, P, exposed.) A small cistern, U, is placed over the receivers, and kept supplied with cold water from the forcing pipe by means of a ball cock, viz.: a cock that is opened and shut by a ball floating in the cistern. From the bottom of this cistern a short pipe, T, proceeds; and to it is connected, by a swivel joint or stuffing-box, another one at right angles. This pipe furnishes water to condense the steam in the receivers, over both of which it can be moved by the rod attached to the plug of the cock as shown in the figure. The upper cistern denotes the place where the water raised by the engine is to be discharged.
“A communication is made between the boilers by a syphon or bent tube, R, whose legs extend nearly to the bottom of the boilers. In the leg within the small boiler is a valve opening upwards, which permits the water of G to pass into H, but prevents any returning from the latter. When the attendant wishes to inject into H a fresh supply of water, he increases the little fire kept up under the boiler G (which is always kept supplied with water by the pipe S), and as soon as the liquid boils and the force of the steam exceeds that in H, the contents of G, both steam and hot water, are forced through the valve; and thus H is kept supplied without the action of the machine being stopped.
“The cock on the pipe S is then opened, the small boiler again charged, and the water becomes gradually heated; so that by the time it is wanted in the other boiler, a small addition to the fuel quickly raises its temperature, and it is again forced in as before. The quantity of water in the boilers was ascertained by _gauge cocks_. These were inserted at the top (see figure) and pipes soldered to them descended to different depths.”
_The modern pulsometer_ is a low-service pump, and is not recommended for duties exceeding about eighty feet total vertical service. With this limitation, its uses are many and various and for some purposes it is particularly adapted. Years of practical work with the pulsometer, under widely different conditions, have demonstrated the merits claimed for it.