. A treatise on pharmacy for students and pharmacists. Glass or metalplummet. SPECIFIC GBA YITY 51 racv for all practical purposes, as water increases its volume from 4°to 100° C. only to the extent of , or about ^. The principle of the loaded cylinder has been utilized in the con-struction of the Mohr specific gravity balance, of which the West-phal modification is a most desirable improvement (see Fig. 31).The specific gravity of a liquid can be quickly taken at any temper-ature between 7° and 30° C, since the loaded cylinder has beenreplaced by a short glass thermometer, which is suspe
. A treatise on pharmacy for students and pharmacists. Glass or metalplummet. SPECIFIC GBA YITY 51 racv for all practical purposes, as water increases its volume from 4°to 100° C. only to the extent of , or about ^. The principle of the loaded cylinder has been utilized in the con-struction of the Mohr specific gravity balance, of which the West-phal modification is a most desirable improvement (see Fig. 31).The specific gravity of a liquid can be quickly taken at any temper-ature between 7° and 30° C, since the loaded cylinder has beenreplaced by a short glass thermometer, which is suspended from the Fig. The Westphal specific gravity balance. end of the beam by a thin platinum wire; the adjustment havingbeen made at 15 C., a slight variation will be observed for anyhigher or lower temperature. The small thermometer has a rangeof twenty-three degrees on the Centigrade scale, and, when suspendedin air from the longer arm of the beam, establishes perfect equilib-rium; when completely immersed in distilled water at 15° C. itdisplaces its own volume of the water aud is buoyed up by a forceequal to the weight of the water displaced—equilibrium of the beambeing re-established by attaching the necessary counterpoise, which 52 GENERAL PHARMACY. is called : at ° C. the necessary weight was found tobe , while at 27° C. it was As seen in the illustration,the longer arm of the beam is accurately divided into ten even spaces,and the weights, or riders, used to counterbalance the thermometerwhen immersed in any liquid, are made of brass and aluminum jthey are so constructed
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Keywords: ., bookcentury1800, bookdecade189, booksubjectpharmacy, bookyear1895
