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.

The activity coefficient and transference numbers of a salt may readily be calculated from the results of measurements of the electromotive force of cells of the proper type without and with liquid junction. The present paper gives values for these quantities resulting from measurements of cells of the type, (0.01 M) I AgCl 1 Ag and of the type, Ag I AgCl I MeC12(c) I MeCh (0.01)M I AgCl I Ag where Me represents barium, strontium and calcium, successively. measurements were made at 25' * 0.01. All The Activity Coefficients The activity coefficients of aqueous solutions of barium chloride have been calculated up to 0.1 M by Lewis and Linhart' from the freezingpoint data of Hall and Harkins.2 These values are valid only at the freezing points of the solutions. The activity coefficients can also be calculated from measurements of the electromotive force of cells without liquid junction. No data are available, however, relative to such measurements for the alkaline-earth chlorides nor have the values of the activity coefficients for strontium and calcium chlorides been calculated from other types of measurement. The electromotive force of cells without liquid junction have been measured in the present study up to concentrations of 1.65, 3.015 and 3.502 M , respectively, and from the results the activity coefficients have been calculated. hpparatus, Materials and Method.-The apparatus used and method of procedurefor the cells without liquid junction were, in general, similar to those described by Mac-Innes and Beattie.a In the present case, however, due to the nature of the amalgam, it was found necessary to make certain changes in the amalgam droppers. It would appear that the amalgams of the alkaline-earth metals are somewhat more viscous than those of the alkali metals. It seemed also that they more readily decomposed upon coming in contact with stopcock grease and other foreign matter in the arms of the droppers and at surfaces of contact with the glass and solution such as the tip of the dropper. Thus, it was found impossible to obtain a continuous electrical contact through the dropper while using capillary tubing in the arms of the droppers. Tubing of about 2mm. bore was therefore used in place of the capillary and in order to prevent the mercury from being drawn out, under the vacuum, the ends of the arms were bent up for about

The present study deals with the mutual miscibility of n-butyl alcohol and wrater, particularly in the presence of added salts. The effect of such substances on the critical solution temperature was investigated by Timmermans (25) for several pairs of liquids, and an extensive study of the systems salts-phenolwater has been made by Patterson and his coworkers (18,19,20,21). They conclude that the elevation of the binary critical solution temperature is the sum of two values, depending on the cation and the anion. The respective ions, when arranged in the order of their effect, form series almost identical with the Hofmeister series. Taylor (24) has made a similar study, and Jacobs (11) has

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