Hand book of calculations for engineers and firemen : Relating to the steam engine, the steam boiler, pumps, shafting, etc. . mple. (Lever 3d kind.) If the power be 1,000 lbs., 3 inches fromthe fulcrum, at what distance must the weight (W) 120 lbs. beplaced to balance it. 1,000 lbs. power. Proof. 3 in. distance. 1,000 3 = 3,000. 120 25 = 3,000. 120)3000 25 inches. Ans. 25 inches from the fulcrum. The Leverage of the Power. The ratio of the power end of the lever, to the length of theweight end, is called the leverage of the poioer. The three varieties of the lever are shown in Fig. 4, 5 and 6,
Hand book of calculations for engineers and firemen : Relating to the steam engine, the steam boiler, pumps, shafting, etc. . mple. (Lever 3d kind.) If the power be 1,000 lbs., 3 inches fromthe fulcrum, at what distance must the weight (W) 120 lbs. beplaced to balance it. 1,000 lbs. power. Proof. 3 in. distance. 1,000 3 = 3,000. 120 25 = 3,000. 120)3000 25 inches. Ans. 25 inches from the fulcrum. The Leverage of the Power. The ratio of the power end of the lever, to the length of theweight end, is called the leverage of the poioer. The three varieties of the lever are shown in Fig. 4, 5 and 6,and in each case the lever is supposed to be seven feet long,and divided into feet. The respective lengths (fig. 4) being 6 feet and 1 foot, theleverage is 6 to 1, or 6. In the second (fig. 5) it is 7 to 1,or 7; in the third one-seventh to 1, or 1-7, showing that inthe first case the power balances 6 times its own amount;in the second case 7 times its amount; in the third case onlyone-seventh of itself, because it is nearer the fulcrum than theweight. Hand Book of Calculations. 57 THE WHEEL AND AXLE, or PERPETUAL Fig. 7. When a lever is applied to raise a weight, or to overcome aresistance, the space through which it acts at one time is smalland the work mast be accomplished by a succession of short andintermitting efforts. The common lever is, therefore, usedonly in cases where weights are required to be raised throughshort spaces. When a continuous motion is required, as in rais-ing ore from the mine, or in weighing the anchor of a vessel,some contrivance must be adopted to remove the intermittingaction of the lever and render- it continuous. The wheel andaxle, in its various forms, fully answers this purpose. It maybe considered a revolving lever. The wheel and axle may be likened, also, to a couple ofpullies of different diameters united together on one axis, ofwhich the larger is the wheel and the smaller the axle, with, acommon fulcrum. The power of the wheel and
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