Magnetic Double Refraction in Liquids

An apparatus for measuring magnetic double refraction (Cotton-Mouton effect) in liquids is described. The chief feature of the apparatus is a very sensitive variable order compensator which is discussed in detail. Measurements made with this instrument indicate that path differences as small as $3\times {10}^{-5\mathrm{}}\lambda$ can be determined with a precision of about 12 percent provided use is made of very intense light having a wave-length lying within the region which corresponds to maximum visual response. The Cotton-Mouton constants of water and several organic liquids of the aliphatic series including four normal alcohols and five normal acetates are reported and compared with the previous determinations made by other investigators. Certain discrepancies are noted and discussed.