CHEMISTRY. 353 



Jones, Harry C, Johns Hopkins University, Baltimore, Maryland. Con- 

 tinuation oj investigations on the absorption spectra oj solutions and on the 

 conductivity and dissociation of electrolytes in water and in non-aqueous 

 solvents at different temperatures. (For previous reports see Year Books 

 Nos. 2-13.) 



A number of problems have been investigated during the year. 



Dr. Davis has studied the effect of certain salts of caesium on the 

 viscosity of water and mixed solvents. It is known that some of the 

 salts of potassium and rubidium lower the viscosity of the water in 

 which they are dissolved. Jones and Veazey proposed an hypothesis 

 which seems to account satisfactorily for this phenomenon. The large 

 atomic volumes of potassium and rubidium diminish the surface friction 

 of the molecules in solution moving over one another, just as larger 

 bullets mixed with smaller shot diminish the frictional surfaces which 

 come in contact with one another when these bodies move over each 

 other. In the light of this suggestion, salts of caesium should show 

 a still greater diminution in the viscosity of water, since caesium has 

 a larger atomic volume than rubidium, which in turn is larger than that 

 of potassium. The experimental facts are in perfect accord with the 

 prediction from theory and are therefore regarded as evidence in favor 

 of the theory. 



Dr. Davis has also studied the viscosities of mixtures of water and 

 formic acid, water and acetic acid, and formic and acetic acids, and 

 compared the results with the viscosities of these solvents in the pure 

 state. This work was undertaken in connection with the suggestion 

 as to the cause of the change in viscosity above referred to. It is well 

 known that a mixture of water and alcohol has much greater viscosity 

 than either pure water or pure alcohol. Both of these solvents are 

 strongly associated hquids. It was shown several years ago, by Jones 

 and Murray, that when two associated solvents are mixed each dimin- 

 ishes the association of the other. Therefore, from a smaller number of 

 larger molecules there results a larger number of smaller molecules, 

 thus increasing the frictional surfaces and consequently the viscosity. 

 Similar results should be obtained when associated liquids, such as 

 those mentioned above, are mixed with one another. The viscosity of 

 the mixture should be greater than that of either pure Uquid alone. 

 The experimental results are here again in perfect accord with the pre- 

 diction from theory. 



Dr. Davis has improved his method for regulating the temperature 

 of baths, his thermo-regulator, all things considered, being one of the 

 best now in existence. He has also devised a new substitute for the 

 twin-bulb trap in toluol-mercury thermo-regulators; and, with L. S. 

 Pratt, has also devised a new form of pyknometer for liquids. 



Dr. Davis and Dr. Putnam have perfected a vacuum distilling 

 apparatus in connection with their work on formamid and have sue- 



