555 



Chemistry. — " Rt'.searc/ws on tfw 7\')nperatu)'e-coe/jicients of the 

 free Surface- ener (j]i of Liquids helivcen — 80° (nul 1650° C.: 

 VII. The specific suiface-energn of the niolteu Halogenides of 

 the Ahali-metals." By Prof. Dr. F. M. Jaeger. (Communicated 

 by Prof. Haga). 



§ 1. Notwithstanding the original intention to publish the results 

 of the measurements concerning llie temperature-coeflicients of I he 

 free surface-energy of molten salts at the same time as the deter- 

 minations of the specific gravities of the investigated salts at different 

 temperatures, and in this waj' to give completely all data, necessary 

 for the calculation of the temperature-coefficients of their molecular 

 surface-energy, — it seemed desirable on account of the present 

 precarious conditions, to resolve already now on the publication of 

 the results hitherto obtained, and relating to the change of the ^/^é^cz/ic 

 surface-energies of (hose salts with the temperature of observation. 

 The present uncertainty about the moment, when the now stopped 

 experiments, necessary for the determination of the specific weights, 

 again vaax be resumed in futnre, makes it perhaps desirable to 

 publish already now the available data of the free surface-energy of 

 some forty salts, and to draw the attention on this occasion to some 

 general conclusions, relating to these measurements. 



§ 2. In this connection it is perhaps of interest to mention here 

 also some details concerning our original tentativeSj to reach the 

 proposed aim by means of the method of capillar ascension-measure- 

 ments, — notwithstanding the fact, that these experiments finally 

 had to be given up because of reasons already formerly explained ^); 

 these details doubtlessly can be of use for later investigations to 

 be made in tiiis direction. 



Originally the investigated salt was introduced into wide tubes of 

 heavily fusible Jena-^XviSS^ provided with rounded bottoms ; (he tubes 

 were heated in a bath of a molten mixture of potassium-, and sodium- 

 nitrate, either by means of gas, or better by electrical current. The salt- 

 mixture was filled into an iron cylinder, outwardly lined with (hick 

 asbestos ; its wall was provided with two diametrically opposed, 

 narrow windows, which were closed by glassplates, fastened by 

 means of asbestos-covered iron-frames. Through these planeparallel 



1) F. M. Jaeger, These Proc. Gomra. I. (1914). 



