272 



SCIENCE 



[N. S. Vol. XXXI. No. 790 



eopceial Convention, led a discussion in regard 

 to matters to be settled at that convention and 

 received suggestions in regard to the policy that 

 should be followed. 



DIVISION OF PHYSICAL AND INORGANIC CHEMISTRY 



Charles H. Herty, Chairman 



Wilder D. Bancroft, Secretary 



Ionization of Salts in Mixtures tvith No Common 



Ion: Miles S. Shekeill. 



That the mass-law does not hold for the ioniza- 

 tion of salts is well known. A thorough examina- 

 tion of data relating to the ionization of salts 

 present in water alone and mixed with other salts 

 has led to the formulation of the following gen- 

 eral principle. 



For any salt the ratio of the product of the 

 concentration of its ions to the concentration of 

 its un-ionized part is a function of the total equiv- 

 alent ion-concentration in the solution and of that 

 alone. 



This rule, originally stated by Arrhenius as ap- 

 plicable to uni-univalent salts and extended by 

 A. A. Noyes to include salts of higher types, has 

 already been confirmed by various investigators 

 through conductance measurements of mixtures 

 with a common ion. 



Tlie conductivity of solutions containing definite 

 mixtures of potassium sulphate and sodium 

 chloride was measured and compared with the con- 

 ductivity calculated with the help of the above 

 stated principle. The agreement confirms the 

 validity of the principle. 



Ionization of Salts in Mixtures toith a Common 



Ion: W. C. Beay and F. L. Hunt. 



The experimental verification by conductance 

 measurements of the principle given in the pre- 

 ceding abstract has been confined to mixtures of 

 salts in which neither component was present in 

 large excess. By taking advantage of the high 

 mobility of hydrogen ion, an extreme case has now 

 been investigated, viz., dilute solutions of HCl in 

 the presence of large excess of NaCl. For each 

 mixture the conductance, when calculated in the 

 assumption that Ah (the conductance of hydrogen 

 ion) is constant, was somewhat greater than the 

 measured value; but the consistent nature of the 

 deviations for all proportions of HCl and NaCl 

 indicated that the ionization of HCl was deter- 

 mined by the total ion concentration and not by 

 its absolute concentration. The transference ex- 

 periments of Noyes and Sammet and Noyes and 

 Kato show, however, that, if ACl remains con- 



stant, Ah increases rapidly with increasing con- 

 centration, and that the degree of ionization of 

 HCl is almost the same as that of KCl. On using 

 these results and assuming that the mobility of 

 hydrogen ion depends only on the concentration of 

 acid in the mixture, the calculated and measured 

 values of conductances were found to agree very 

 closely. 



Heats of Comiustion of Certain Liquid Hydro- 

 carhons: T. W. Bichakds and R. H. Jesse, Jb. 

 In further prosecution of the -revision of 

 thermochemical data the heats of combustion of 

 benzene and a number of octanes and xylenes 

 were determined with unusual care. The object 

 in choosing these substances was to endeavor to 

 trace the effect of constitution or arrangement 

 upon the heats of formation of isomeric sub- 

 stances and thus to obtain more definite idea of 

 the relation of total energy-change to structure. 

 Tlie adiabatie method of calorimetry was used 

 with great success, and in general the precau- 

 tions used in previous work of this kind were 

 adopted throughout, with several new improve- 

 ments. Each specimen of volatile liquid was 

 sealed in a flexible flattened glass bulb and ig- 

 nited by means of a small weighed quantity of 

 sugar placed above the bulbs on a glass shelf, the 

 substances being contained in a very small narrow 

 platinum crucible. When conducted in this way, 

 the combustion was in every case complete. The 

 final results showed veiy satisfactory agreement 

 among themselves, and all will be soon published. 

 This investigation will be continued in the near 

 future, and the effort will be made to obtain as 

 much light as possible upon the energy relations 

 of these closely related compounds. 



The Compressibilities of Certain Isomeric Hydro- 

 carbons: T. W. Richakds and C. L. Speyees. 

 In continuation of the work upon compressi- 

 bility, described in Publications 7 and 26 of the 

 Carnegie Institution of Washington, and in con- 

 nection with the work above summarized concern- 

 ing the heats of combustion of octanes and xylenes, 

 the compressibilities of these substances at various 

 temperatures was investigated in detail. The ef- 

 fort was made to attain greater accuracy than 

 ever before. The standard of pressure was veri- 

 fied to a degree of precision far exceeding anything 

 which had hitherto been attained. The new 

 method for determining compressibility was 

 found to give satisfaction as before. Five octanes 

 were investigated with great care. Their com- 

 pressibilities were found to vary over a much 



