571 



temperadires, the enormously high absolute values of / with these 

 salts, which may occasionally be more than three times that of 

 ivater, must be considered as very remarl^able. In connection with 

 the data giveu above, we can moreover generally conclude: 



1. The temperature-coefficient h of the specific surface-energn 

 decreases continually in the case of the four halogenides of the same 

 alcali-metal, ivith increasing atomic weight of the halogen-atom. This 

 rule holds evidently quite accurately in all the cases here considered. 



As to the absolute values of x of these salts, attention can more- 

 over be drawn to the following general rules : 



2. At the same temperature t, the values X( for the same halogenide 

 of all alcali-metals, will decrease gradually luith increasing atomic 

 loeight of the alcali-metal. 



3. At the same temperature t the values y^f will gradually decrease in 

 the case of the four halogenides of the same alcali-metal, loith increas- 

 ing atomic weight of the halogen-atom. 



These relations however do not possess a simple «-^fW/^/y^ character. 



Generally speaking, the Z^'-compounds appear to deviate more 

 from those of the other alcali-metals. than these from each other; 

 the K-, Rb-, and 6Vcompounds approach each other more, than 

 each of these elements do the corresponding iVcz-compounds, while 

 in the series of the first mentioned three alcalimetals, the compounds 

 of K and Rb appear to have the nearest analogies to each other. 

 Probably the liquid lithium-salts may possess a higher degree of 

 molecular complexity, than the salts of the other alcali-metals. 



Groningen, Augustus 1914. Laboratory f or Inorganic and Physical 



Chemistry of the University. 



Chemistry. — ''Researches on the Temperature-coefficienis of the 

 free Surface-energy of Liquids at Temperatures between 

 — 80° and 1650*^ C. VIII. The Specific Surface-energy of 

 some Salts of the Alcali-metals.'' By Prof. Dr. F. M. Jaeger. 

 (Communicated by Prof. H. Haga).' 



§ 1. As a sequel to the data published in the foregoing com- 

 munication, which related to the halogenides of the alcali-metals, 

 the results of the measurements made with a number of salts of 

 the alcali-metals. which belong to some other series, are communicated 

 in the following pages. These measurements include the following- 

 objects : 



