Wells's principles and applications of chemistry; . ced in a narrow vessel or jar (see Fig. 9), and the zero point on thescale of the hydrometer is always placed at that point where the instrumentwill float In pure water. The numbers on the scale read either up or down,according as the hquid to be tested is ejther heavier or lighter than water. For the testing of alcohol and spirituous hquors, a particular form of hy-drometer is used, called the alcoholometer. This is so graduated as toindicate the number of parts of pure alcohol in a hundred of liquid;—^perfectlypure, or, as it is called, abs
Wells's principles and applications of chemistry; . ced in a narrow vessel or jar (see Fig. 9), and the zero point on thescale of the hydrometer is always placed at that point where the instrumentwill float In pure water. The numbers on the scale read either up or down,according as the hquid to be tested is ejther heavier or lighter than water. For the testing of alcohol and spirituous hquors, a particular form of hy-drometer is used, called the alcoholometer. This is so graduated as toindicate the number of parts of pure alcohol in a hundred of liquid;—^perfectlypure, or, as it is called, absolute alcohol, being 100, and pure water 1. In the arts, a French hydrometer, kno\\Ti as Beaume^s, and an English in-strument knowm as Twaddells, so called from their makers, are much and manufacturers of spirituous liquors, syrups, oils, leys for soap-making, etc., in buying, selling, or compounding, are accustomed to indicatethe strength or quahty of their products, by saying that they stand at so manydeo-rees Eea-ume, or QuEETioxs.—^What is a hydrometer ? Upon what principle may the specific gravityof a liquid be determined by the hydrometer ? How is the hydrometer graduated ?What is an alcoholometer ? WTiat are the instruments known as Beaume and Twad-deU? COHESION. 29 The practical value of the hydrometer in the arts as a labor-saving inven-tion, is very great. The soap-maker, by dipping the instrument into his ley,and noticing the point at which it floats, knows at once by experience whetherit is of sufficient strength to convert his grease into soap ; the salt-boiler, bya like observation, is enabled to judge how long his brine must be boiled be-fore salt will deposit at the bottom of his kettles; and the bleacher has in alike manner a sure check against the use of bleaching liquors of strength suf-ficient to damage his fabrics. So in very many other industrial processes alsothe hydrometer is equally useful. 41. Specific Gravity of Gases.—In
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Keywords: ., bookcentury1800, bookdecade1860, booksubjectchemistry, bookyear18
