Pulirich Refractometer, for the measurement of the refractive indices of both solids and liquids with an accuracy of about .0001; and also for dispersion (the difference refractive index for two spectral lines) to about .00002. In this apparatus the substance whose refractive index is required is placed on he horizontal surface of the prism supplied. If this substance is a solid it must have two faces worked at right angles to each other, so that one may rest on the horizontal surface of the prism. In case of a liquid this is contained in a glass cell cemented to the prism. A beam of monochromatic light is directed almost horizontally through the substance, so that it meets the prism face at grazing incidence. The emergent beam is bounded sharply by that ray which actually grazes the prism surface, and the sharp boundary is observed with telescope attached to a circle. A condensing lens and supporting rod for vacuum tube are supplied. The refractive index to be measured must be less than that of the glass of the prism.
With prism of refractive index for D of 1.74 suitable for substances of index between 1.47 and 1.73, with mount and carrier and improved water jacketting attachments; in case with lock and key
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