1202

THEORY AND PRACTICE OF ENGINEERING.

Book 11.

small pump-barrel, at the same time closing the lower and opening the upper valve in thepipe G L. The axle Q having now arrived at M L, the cock will make a quarter of a

rsvoluticn in the opposite direction, closing the supply pipe and opening that of the dis-charge ; the water in the great pump-barrel will cease to act against the piston S, and at

Fig. 1880.