The system cyclohexane-methyl alcohol was first studied by Lecat (8), and the phase data from this investigation are compiled in the International Critical Tables (6). According to these data the critical solution temperature for the system is 49.1°C. In 1926, Mondain-Monval (10) published results on the heat changes produced on mixing cyclohexane and methyl alcohol at various temperatures, from which the phase relationships are deducible. A more careful investigation of this system than had been made previously was undertaken by Jones and Amstell (7), who extended their researches to the effects of added substances on the miscibility temperatures. They studied, as third components, water, acetone, and benzene, and established a method for determining the amount of water in methyl alcohol. According to these workers, the critical solution temperature of the two-component system is 45.60°C. In 1934, Washburn and Spencer ( 16) studied the three-component system cyclohexane-methyl alcoholwater, noting the distribution of methyl alcohol between water and cyclohexane and the freezing-point relationships. The present investigation was undertaken to determine the phase equilibria when various inorganic salts are present. EXPERIMENTAL Purification of cyclohexane Commercial cyclohexane and even better grades are likely to contain impurities due to foreign matter originally present in the benzene together with isomers and products of incomplete hydrogenation. Methylcyclopentane frequently is present and boils only 7°C. below cyclohexane. These two substances are very similar in other respects and their separation is difficult. Seyer, Wright, and Bell (13) have shown that the purification of cyclohexane can best be achieved by efficient rectification, and this method was used in the present work.A fractionating column employing 5-mm. glass helices as packing material was constructed especially to purify cyclohexane. The central tube of the column was 1.9 cm. in diameter and packed for a height of 3.36 meters. Adiabatic 1 This article is based upon a dissertation submitted by E. L. Eckfeldt to the Faculty of the Graduate School of the University of Pennsylvania in partial fulfillment of the requirements for the degree of Doctor of Philosophy, February, 1942. 2 Sincere thanks are due E. I. du Pont de Nemours and Company, Inc., for a Postgraduate Fellowship for the academic year 1940-41.

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In 1888, while investigating the salting out of natural egg albumin from aqueous solutions, Hofmeister (12) found that the various ions were effective to different extents and arranged the two groups in their resulting order. Later Pauli (18) modified and extended the series, giving for the salting out of albumin: