This and a previous investigation (10) were undertaken to obtain data to be used in the study of distillation of ternary mixtures. The densities, surface tensions, viscosities, refractive indices, and specific heats for the ternary system ethyl alcohol-glycerin-water are reported in this paper. A later paper will contain latent heats, boiling points, vapor pressures, and liquid-vapor composition data for the two ternary systems.Densities (4), specific heats (13), refractive indices (11), and viscosities (19) of the binary system glycerin-water have been determined previously by various experimenters. The binary system ethyl alcohol-water has been investigated by Bose (6), who determined specific heats, and by Winkler (22) for density. This investigation includes the determination of densities, surface tensions, viscosities, refractive indices, and specific heats of the ternary system ethyl alcohol-glycerin-water. EXPERIMENTAL Materials. Glycerin of the c.p. grade was purified by repeated distillation under reduced pressure, c.p. ethyl alcohol was treated successively with metallic calcium, sodium hydroxide, and finally with metallic sodium, and distilled after each addition. The water was treated with potassium permanganate and distilled; then treated with barium hydroxide and distilled repeatedly. The physical constants of the purified materials are given in table 1. Preparation of samples. The samples were prepared on a weight per cent basis in increments of 10 per cent. The composition of these samples is shown in table 2.Apparatus. Densities were determined by using a Geissler pycnometer. An Ostwald-Poiseuille viscosimeter (23) was employed for the determination of viscosities. The surface tension was measured by means of the 1 Presented before the Division of Physical and Inorganic Chemistry at the Mid-West Regional Meeting of the American Chemical Society, October 31 to November 2, 1935.

Tephrosinmonocarboxylic Acid.-When isotephrosindicarboxylic acid was boiled for one-half minute with diphenyl ether, tephrosinmonocarboxylic acid was formed in essentially the same yield as recorded for tephrosindicarboxylic acid.1 As obtained from the cooled diphenyl ether solution upon the addition of methanol the acid melted at 266-268°, and when it was mixed with an authentic sample of tephrosinmonocarboxylic acid no depression of the melting point occurred. It also gave the characteristic scarlet color with ferric chloride that is obtained with tephrosinmonocarboxylic acid. Summary A crystalline material, shown by its composition and certain of its derivatives to be an isomer of tephrosin, has been obtained from a sample of Peruvian cubé root. This substance has been designated as isotephrosin. The structural difference between tephrosin and isotephrosin exists in the orientation of the hydrogen and hydroxyl groups on carbons 7 and 8 in the structure given in the text.