Chap. XVII.

ON MACHINES FOR RAISING WATER.

1191

pounds is to 1728 inches, so is \p, to a fourtli term, or this divided by 84 feet or 1008

inches, gives ^ s p for the superficies of the pistons, which multiplied by gives the squareof the diameter, and being reduced gives £ z p, the root of which will be the required diameter.Supposing the force of the fall of water to be 110 pounds on each float-board of the wheel,substituting this number for />, we shall have 12 square inches, whose root gives 3^ inchesfor the diameter of the pistons : although both the wipers X and Y are capable ofexerting a force expressed by 3p , those only which act on EV will exercise it entirely,since those levers alone suck and force the water; the other wipers Y only exercise asmall portion of their force; the lever G not acting uniformly, the wheel turns more rapidlyat one moment than at another. A second defect in this machine is caused by the wiperX not pressing equally on S F, because the direction in which it acts changes at every pointof its course, as well as the length of the lever V S, which continually increases: to rectifythis evil the wiper X, in place of being straight, should have the figure of an epicycloid.

Fig. 1843. is a more simple manner of arrangingthe same machine, invented by M. Morel. Thewheel A is driven by a fall of water; its axle has twohalf wheels 13, C, placed on the same side and about3 feet apart, to work the pumps, which is performedby two racks attached to the piston rods, working inguides D, E : one of these is loaded with a weightF, to make the rod of the suction pump H descend.

At the end of the other a cord is attached, passingover two pulleys, and carrying a weight G to raise therod of the forcing-pump I; each rod has a stop to limitthe stroke when it meets the guides. The wheel A,by driving the half wheel B, raises the piston rod D,and as soon as it escapes the rack, the weight F bringsit down. On the other hand the weight G keepingthe rod E at a proper height, when the half wheelC engages the rack of this rod, it drives it down andforces -the water in the pump I up the dischargingpipe K ; the weight G then again raises the rod ; thusthe pistons suck and pump alternately. As the wheelB will only allow a small power to raise the water24 feet high, and surmount the resistance of the weightF, plus that of the piston, whilst, on the contrary, thewheel C acts with much greater force on the rod Eto overcome at the same time the resistance of theweight G and that of the column of water which thepiston forces to the height of 60 feet, the wheel Awill turn unequally.

Fig. 1844. is a machine executed at Nymphen - g

bourg by Count Wahl, director of builders to the ' 8 '

Elector of Bavaria , to raise water to a height of 60 feet, for the fountains in the gardensof the electorate. A stream turns a large wheel, which carries two cranks, working two

Fig. 1845.

Fig.1844.

4 c 4