抄録
Method of preparing large single crystals of alkali-halide in laboratory had been reported by the author1). Using these crystals, various optical parts have been made. In response to the requirement of physicists engaged in the research of infra-red spectroscopy and the study of ionic crystals, the method of polishing is given which is similar to the polishing of glass but with special caution on account of deliquescence and softness.
