Abstract
A MONGST the physical properties which are characteristic of a substance, the refractive index is one of the most important. From a theoretical point of view, the fact that refractivity is mainly an additive quantity—the molecular refractivity being approximately the sum of the atomic refractivities—is highly significant. From a practical point of view, the ease and accuracy with which refractive indices can be determined by modern methods are of great service, both to the physicist and to the chemist, in the examination of the materials with which they have to deal. Whether for purely scientific or for technical purposes, such a determination affords a rapid method of finding the concentration of solutions and the purity of oils, fats, waxes, and foodstuffs. New applications are continually arising in a variety of industries dealing with drugs, sugars, paints, varnishes, glue, gelatine, and other colloids. The physicist finds the method of service in the identification of optical glasses or in the study of singly or doubly refracting crystals.
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Refractometers . Nature 103, 145–147 (1919). https://doi.org/10.1038/103145c0
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DOI: https://doi.org/10.1038/103145c0