1190

THEORY AND PRACTICE OF ENGINEERING.

Book II.

G and II should work in guides to maintain their vertical position. The arm of the winchA should be 1 foot long, the fly-wheel 6 feet in diameter, the pinion 15 4 inches, C andD 16 inches, E and F 4 inches in radius from the centre to the middle of the teeth.There being four levers between the power and the weight, viz. the arm of the winch12 inches, the radius of the pinion 2, that of the wheels C and D 8, and F and F 4, thepower will be to the weight as 2 x 4 to 12 x 8, or 1 to 12 ; consequently a man with a forceof 2 5 pounds can raise a column of water of 300 pounds.

Fig. 1842. is a machine executed at Sources, a village of Alsace , on the road fromStrasburg to Landau, placed over a large square well, the water of which is used formaking salt. There are three floors, at 10 or 12 feet apart; the framework of carpentry, A,is placed on the first at the edge of the well, the cylinder 15 on the second, and the chest Con the lowest. A fall of water drives the wheel D, the axle of which, E, has 4 catches, X,Y,or wipers, which successively depress the levers F,G, and move the cylinder 15 by means ofiron rods at the extremity of thebalance K. Another balance, N,carries the piston rod, whichis alternately elevated anddepressed. The suction-pumpII raises the water to the cisternC about 24 feet; the forcing andsuction-pump I then drives itup the tube L 60 feet higherto the reservoir near the saltworks. The dimensions for asimilar machine will be nearlyas follows:—the great water-wheel 5 feet in radius; thewipers X,Y* 20 inches in lengthfrom the centre of their axle;the lever FV 5 feet 10 inchesfrom its fulcrum to the point onwhich the wipers lean; thepoint T, to which the rod isattached giving motion to thebalance K, is 5 distant from thefulcrum V, and the pistons eachhaving a lift of 12 inches ; theextremity of the wiper X mustpass over a certain determinatelength S F of the lever V F, inorder that the point T, whichhas the same movement as thepiston, may rise 12 inches anddescend as much, whilst thewipers will act alternately onthe levers F and G : if the wiperdoes not escape the lever F atthe instant the piston reachesits lowest point, the machineceasing to act may break someportion, for the wheel D con-tinuing to turn will tend tosurmount any obstacle whichmay prevent it. If, on theother hand, S F be too short,the wiper will not make thepoint T descend low enough,and the piston not having a lift of 12 inches, the effect of this machine cannot becalculated on such data. The water-wheel must be considered as of 5 feet radius; thewiper X 20 inches in length, the power P will be to the effort made by the wiper on thepoint S as 1 to 3, and reduced to the point S may be expressed by 3/?, when the lever F Vand the wiper X are in the same line: now, as the lever is of the second order, the pow'erwhich will act on the point S will be to the effort which it will produce at the point T, todivide the rod downwards, as V T to Y’ S, or as 6 to 7 ; the effort at the point T may then beexpressed by Ip . To find the diameter of the pump barrels,—since II sucks while Iforces, they will together sustain the weight of a column of water 84 feet high. To findthe base of this column in square inches, reduce Ip into cubic inches, hv saying as 70

Fig. 1842.