2877. B÷ttcher, E. Feb. 8. Water-pressure engines. -The distributing piston valve is reversed by pressure water taken from the connecting ports between the distributing valve casing and the working cylinder, thereby relieving the pressure on the valve immediately reversal is effected. The working cylinder 5, No. 1, is reciprocated upon a fixed piston 1, but the cylinder may be fixed and the piston reciprocated. The fixed piston-rod 4 is connected to the frame 3 of the machine, and upon the cylinder is fixed a driving- bar 9 which oscillates a toothed wheel, shown by dotted lines, to drive washing or other machines. The distributing piston valve consists of four pistons 11 rigidly connected together, the middle two controlling the admission of water from the inlet 12 to the working cylinder through the ports 13, and the outside ones, in combination with the middle two, controlling the exit of water from the working cylinder to the exit port 14 and pipe 15, Fig. 3. At the ends of the stroke of the working cylinder, the distributing piston valve is reversed by means of pressure water admitted to the outer end of one or other of the outside pistons 11 from the connecting port 13 through ports 17, 16, 18, Figs. 1, 3, and 4, the admission of this water being controlled by piston-rods 19 arranged at each end of the exit port 14 and connected together. When the working cylinder reaches the end of its stroke, a pin 22 strikes a projection 23 on the frame 3 and shifts the piston 19, thus uncovering the port 18 to admit pressure water from the port 13 through an opening 24 into the distributing casing 10, whereby the piston valve 11 is thrown to the other end of its casing 10. The opening 24 is slightly longer than the piston valve 19 in order to allow the water behind the valve 11 to pass, on reversal, to the outlet 14 when the valve 19 is at its extreme position. Simultaneously with the reversal of the distributing piston valve 11, the port 13 is cut off from the pressure pipe 12, and the pressure behind the piston valve 19 is relieved. When the piston valve 19 and distributing piston valve 11 are reversed, part of the water behind them flows back to the port 13 and thence to the outlet 15, and when the piston valve 19 covers the port 18, the remaining water passes through a very small port in the valve 19 to the exit 14. This port is too small to interfere with the action of the valve. A modification is described in which the piston valve 19 is dispensed with, and the admission of water from the port 13 to the distributing-piston 11 is controlled by the valve itself. The port 18, in this case, opens into the casing 10, and at the end of the stroke of the working cylinder, the valve 11 is shifted by a pin striking a projection 23 on the frame 3, thus uncovering the port 18 and admitting water from the port 13 to throw the distributing piston valve to the other end of the casing. Small ports through the end pistons of the valves 11 serve to carry away water from the ends of the casing as before described.