Chap. XVII.

MACHINES FOR RAISING WATER.

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mended this machine to the attention of the engineer; its enlarged part occupied three-fourths of its circumference, and was nearly 8 inches in diameter at the outer end ; theenlarged portion contained 6844 cube inches, and the spiral revolved six times in a minute,raising in that time 22 cubic feet of water 10 feet high : when I)r. Young made his experi-ments upon the Archimedean screw, he found that it required such a length of pipe, thatit became inconvenient when the water was to be raised to anv very considerable height.

MM. Denisard and de la Dueille executed at Sevres, between Paris and Versailles , amachine for raising water by a natural fall, shown in fig. 1885. : it consists of a woodenframework in which is a basin with two boards placed on each other, and hollowed out toform the basin, which is lined with leather; in it is a piston of nearly the same diameter,attached thereto by a piece of leather, in such a manner as to have a stroke of only 3 or 4inches: four pipes are adapted to this basin ; the supply pipe I T, the branch Z Z, thewaste F, and the descending pipe G. The long screw with two nuts Y,N, raises and lowersthe balance-beamconsisting of twobasins O, Q, withpipes of commu-nication to allowthe water to passfrom one to theother : at the ex-tremities of thisbalance-beam arerods which openand shut valves inthe waste and sup-ply pipes : theseare representedin figures 1838.

1834. 'Hie valveis enclosed in .asmall coder, A B,in which is a trun-cated cone, fittedto the pipe. Thecover of this coneis attached to anaxle C, and thislatter to the rod E,which the balance-beam works. Thepart 1 of the valve(fig. 1883.) beingstopped by thecone, and thewhole valve beingimmersed, the co-lumn of water tobe raised is inproportion to thediameters of thebases. When the

rod E descends, the solid cone, which has a contrary motion, will unstop the hollowed cone I,and the water will without difficulty pass into the tubes D, R; if, on thecontrary, the waterraisethe rod E, the valve closes, and the pipe will be stopped. The source L being 10 feet high, thewater will introduce itself by the pipe IT V below the piston A, which being driven by thiswater will naturally rise, at the same time driving out the water above at B, through thewaste pipe F ; by this elevation the nut N raises the balance-beam, and the water passes fromthe basin O to Q; the extremity O raises the rod It, which closes the valve H ; the basin Q.resting on the rod S opens the valve X, in the descent pipe G, and the water from thesource, taken from below the great piston, rises by the branch Z Z. The pipe V beingstopped, the piston is loaded with the weight of water in the descent pipe G : by itsdescent the balance-beam is drawn down, and the water returning from Q to O closes thevalve X and opens H : the water is thus raised in succession.

Some alterations were afterwards made in this machine in order to raise the water in acontinuous stream ; this disposition is shown in fig. 1886. Hie source A furnishes waterby the pipe ABC below the lower piston D; this source is supposed to be 10 feet high.

4 h 3

Fig. 1885.

dueille’s machine.