The machine under consideration, being one that produces a moderate quantity of ice, has but a single chamber, as shown in Figs 4, 5, and 6. It is a suction and force pump, whose piston, E, is solid and formed of two parts, which are set into each other, and the flanges of which hold a series of bronze segments. [Illustration: VINCENTS ICE MACHINE. FIG. 6.--PLAN OF THE PUMP.] The chamber, properly so-called, is of iron, cast in one piece, and is surmounted with a rectangular tank, F, in which constantly circulates the cold water designed for cooling the sides of the cylinder; these latter always tending to become heated through the compression of the methyl chloride. The cylinder heads are hollowed out in the middle, and carry the seats of the suction valves. Each of the latter communicates with a chamber, G G¹, in which debouches the pipe, H, communicating with the cylinder, A, of the freezer (Figs. 1, 2, and 3). [Illustration: VINCENTS ICE MACHINE. FIG. 7.--THE LIQUEFIER.] Above the cylinder there are two delivery valves which give access to the chamber, D, communicating with the worm of the liquefier (Fig. 7) through the pipe, J. The piston of the pump is set in motion by a pulley, K, and a cranked shaft actuated by a belt from the shafting. The piston head is guided by a slide keyed to the frame. [Illustration: VINCENTS ICE MACHINE. FIG. 8.--SECTION OF FLANGE OF THE WORM.] _The Liquefier_.--This apparatus consists of a cylindrical tank, L, of 3 mm. thick boiler plate, mounted vertically on a masonry base and designed to be constantly fed with cool water. It contains a second cylindrical tank, M, of 6 mm. thick galvanized iron. This latter tank is provided with a cast-iron cover, on which are mounted the worm, N, and a pipe, O, connected with the tube of the pressure gauge. To the base of the tank, M, there is affixed, on a cast iron thimble, a cock, P, for setting up a communication between the tank and the pipe, R, which returns to the freezer through the cock, B (Fig. 1). [Illustration: VINCENTS ICE MACHINE. FIG. 9.--VIEW OF THE UNDERSIDE OF THE SAME.] The cold water requisite for condensation enters the tank, L, through a pipe terminating in a pump or a reservoir. The waste water flows off through the tubulure, Q. The tank is emptied, when necessary, through the blow-off cock, S. [Illustration: VINCENTS ICE MACHINE. FIG. 10.--PLAN OF THE WORM.] _Operation of the Apparatus_.--As has been remarked above, the cylinder, A, is filled with chloride of methyl. The pump, through suction, produces in this cylinder a depression from which there results the evaporation of a portion of the chloride of methyl, and consequently a depression of temperature which is transmitted to the incongealable liquid circulating in the tubes, and to the receptacles (carafes or otherwise) containing the water to be converted into ice.