32 



SCIENCE. 



[N. S. Vol. IX. No. 210. 



THE CHEMICAL SOCIETY OF WASHINGTON. 



The regular meeting was held ou November 

 10, 1898. 



The first paper of the evening was read by Mr. 

 F. K. Cameron, and was entitled ' Some Boiling- 

 point Curves for Mixtures of Miscible Liquids. ' 

 The general properties and significance of 

 pressure-concentration and temperature-con- 

 centration curves for pairs of perfectly miscible 

 liquids were indicated, and the researches 

 of Konowaloflf, Nernst and others briefly cited. 

 All the possible types now known were illus- 

 trated by some as-yet-unpublished data from a 

 preliminary investigation by Cameron and 

 Thayer. A significant fact brought out by cer- 

 tain of these curves, notably the one for alco- 

 hol-chloroform mixtures, is that they possess 

 not only a maximum and minimum point, but 

 there is a decided sag in the opposite direction 

 at another portion of the curve. So far no 

 such curve is known which has both a maximum 

 and minimum point, and the possibility of such 

 a case has been denied by some authorities. 

 But the fact just cited shows an indubitable 

 tendency towards such a case and indicates 

 that by a suitable choice of the constant factor 

 (temperature or pressure) for some pair of 

 liquids such a curve may yet be found. The 

 great desirability of further experimental work 

 in this field, both for theoretical and practical 

 reasons, was indicated. 



The second paper was by Mr. F. K. Cam- 

 eron, and was entitled ' A Ternary Mix- 

 ture.' Given a mixture of two perfectly 

 miscible liquids, A and B, and a third sub- 

 stance, C, soluble in one constituent of the 

 pair, at a definite temperature there will be 

 a separation of the liquid mixture into its con- 

 stituents, this definite temperature being de- 

 pendent on the relative concentrations of the 

 solution. By keeping C in excess of the amount 

 soluble the problem is somewhat simplified. 

 The results of a preliminary Investigation on 

 the curve for temperature of separation-con- 

 centration, presence of a third substance solu- 

 ble in only one constituent, were presented. 

 Further, the third substance, C, was varied for 

 certain concentrations. And, finally, mixtures 

 of the substances which had been used as C 

 were tried. The results were interesting, but 



no causal connection could be detected. It is 

 essential that more experimental evidence shall 

 be in our possession before a satisfactory theory 

 of the phenomena will be possible. 



The third paper was read by Dr. T. M. 

 Chatard and was entitled ' Note on the Kate 

 of Loss in Cyanide Solutions.' Dr. Chatard ex- 

 hibited a sheet of curves representing the rate 

 of loss of cyanide in solutions used for the ex- 

 traction of gold in the electrolytic sluice. There 

 is always a certain loss due to oxidation of the 

 cyanide through agitation of the solution dur- 

 ing the operation of the apparatus. Another 

 loss results from the action of the ore on the 

 solution. An electric current of about 0.2 amp. 

 per sq. ft. of cathode plate and of about 2 volts 

 is employed, and it is desirable to know what 

 effect such a current has upon the solutions 

 which usually contain from 0.20 to 0.25 per 

 cent. KCN at the start. Samples of the solu- 

 tion were taken at regular intervals during 

 each run, the percentage of cyanide giving 

 points of the curve. When ore is treated, the 

 curves usually show a rapid loss of cyanide dur- 

 ing the first period of fifteen minutes, due to the 

 action of the ore, the rate of loss then deci'eas- 

 ing so that the final result is often a fairly reg- 

 ular curve. When the solution is run with 

 neither ore nor current the fall in strength is 

 usually regular, so that the line connecting any 

 three consecutive points is practically straight. 

 Using the customary current but no ore, other 

 conditions being alike, the results indicate that 

 the cyanide losses are lessened even though the 

 tests are, as yet, too few for positive evidence. 

 It may, however, be stated with confidence that 

 the use of electricity, so important for the ex- 

 traction of precious metals from ores and solu- 

 tions, is not attended by any increased loss of 

 the expensive cyanide. 



The last paper was read by Dr. C. E. Munroe 

 and was entitled ' The Examination of Acid 

 for Use in the Manufacture of Gun-cotton.' 

 Dr. Munroe's paper contained a summary of 

 work done by his assistants, Mr. G. W. Patter- 

 son and Mr. J. J. Tobin, and by him. The 

 specifications for the acids given were accom- 

 panied by descriptions of the analytical methods 

 and methods of calculation to be followed in 

 the inspection of the acids supplied, and a com- 



