tubes is closed by two ring-shaped pieces. This vessel may be about 18 inches high; a cock is fixed in the top of this vessel, to which a bent pipe is fastened, leading to and united with a pipe which arises from the top of the condenser and passes through a hole in the cap-piece, and thus a communication between the supplying vessel and the condenser may be opened or shut at pleasure; another pipe, also furnished with a stop-cock, arises from the vessel, and communicates with a water-cistern to receive its supply of water when required; a third pipe, having a cock in it, opens into the vessel near the bottom to let out the sediment; a small cock to let the air out is also fixed in the top of the vessel, which cock may also be used for letting air out of the condenser. In order to supply the boiler with water by means of this vessel, the stop-cock leading to the condenser is shut, and that leading to the cistern is opened, and at the same time the air-cock is opened to allow the air to escape that the water may fill the vessel. When the vessel is nearly full of water, the air-cock and the cock from the cistern are shut, and that in the pipe leading to the condenser is opened. The water being then heated by the flue is converted into steam, which, passing into the condenser, is there reduced to water again, leaving the sediment or salt in the supplying vessel, which sediment or salt may be occasionally blown out through the bottom pipe by filling the vessel with, water, shutting the water, steam, and air cocks, and opening the cock of the outlet pipe at a time when the steam in the vessel is strong. But the supply of water from the condenser being always equal to that converted into steam and used in the engine, there is no tendency to a variation in the height of the water in the boiler, except there be leakage or waste of steam in some part of the engine. An upright glass tube, having an iron tube of communication with the lower part of the boiler and another iron tube of communication to the upper part of the boiler, is conveniently placed against the outside of the air-vessel to indicate at all times the height of the water in the boiler; as is usual in steam-boilers, a valve is placed on the top of the air-vessel to allow of the escape of a portion of the air in case that the quality of the fuel should not require so much air for perfect combustion as the steam requires for good condensation. The degree of the condensation of the steam may be increased at pleasure, by increasing the velocity of the air passing into and through the air-vessel. The other parts of my improved steam-engine, such as the steam-pipes, the throttle-valve, the safety-valve, the vacuum-valve, the working valves, crank, connecting rods, cross-heads, pistons, piston-rods, and various other minor parts common to engines in general use may be made in the usual forms, and placed in the most convenient situations;