. The Pharmaceutical era. n a liquid one of three things may occur: It may sink to the bottom,float indifferently at any point, or rest on the surfacewith only its lower portion immersed. Which positionit lakes depends upon the relation of its weight to that ofan equal bulk of the liquid. If it is heavier than an c(|ualbulk of the liquid, it sinks. If it is just as heavy, theeffect is the same as the addition of so much of thatliquid, and it will consequently float wherever the solid is lighter than an equal bulk of the liiiuid,it will sink just sufficient to displace its own weight.
. The Pharmaceutical era. n a liquid one of three things may occur: It may sink to the bottom,float indifferently at any point, or rest on the surfacewith only its lower portion immersed. Which positionit lakes depends upon the relation of its weight to that ofan equal bulk of the liquid. If it is heavier than an c(|ualbulk of the liquid, it sinks. If it is just as heavy, theeffect is the same as the addition of so much of thatliquid, and it will consequently float wherever the solid is lighter than an equal bulk of the liiiuid,it will sink just sufficient to displace its own weight. Loss of Weight. Principle ot Archimedes.—If a piece ofmetal Im- first weighed in air. Ilicn attached by a threadto the balance beam, immersed in water and againweighed, it will \k> found to have lost in weight, i. e.,that it is buoyed up by the water. (Fig. 27.) What is the amount of loss in weight? It is evidentthat the metal displaces its own bulk in the liquid. Ifthe experiment be made in a graduated jar, and the. Fig. 26.—The .Siphon. amount of rise in the liquid noted when the metal isimmersed, then that quantity of liquid poured out andweighed, its weight will hv found to be the weight whichthe metal has apparently lost. No matter how often theexperiment be tried the result willbe the same. It is evident, there-fore, that when a solid is im-mersed in a liquid, its loss inwiight is equal to tin: weight of ancijiial hulk of the, liquiil. This is known as the principleof Archimedes, and must be thor-oughly comprehended by the stu-dent before the subject of specificgravity can be properly under-stood. Density.—If we should compareequal cubes of iron, lead, coal,wood, etc., it would be found that, though equalin volume, they possess quite different is owing to the fact that they contain differentquantities of matter in the .same space, or that theydiffer in density. Hence density is defined as the quan-tity of tnattcr iu a unit of vuluiiie. If metric wei
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Keywords: ., bookcentury1800, booksubjectdrugs, booksubjectpharmacy, bookyear1
