k 397 
If now it is once more remembered that u == 4. v7, it must be 
clear, that the cause of this phenomenon can only be found in the 
supposition, that » is no longer a comparable thing in these series 
of homologous salts. A suspicion arises more particularly that it is 
no longer permissible to take in account for the molecular weight M 
M 
during the calculation of » = —, the values, following from the 
a 
mere chemical formula of these salts. The significance of this would 
become evident, if one could suppose, that the degree of dissociation 
a of every one of these salts is a different one at the same temperature. 
Thus an indirect indication would be found here for the decision 
of the problem not solved completely up to this date; if molten 
salts must be considered to be electrolytically dissociated only parti- 
ally or totally; and more particularly this question would be defi- 
nitively answered in favour of the partial dissociation, when «< 1. 
In how far this conclusion with respect to this fundamental problem 
may be considered to be justified, we also hope to discuss shortly 
in a second way, in connection with experimental data of another kind. 
Groningen, Holland, June 1916. 
Laboratory for Inorganic and Physical 
Chemistry of the University. 
Chemistry. — “/nwestigations on the Temperature-Coefficients of 
the Free Molecular Surface-Lnergy of Liquids between — 80° 
and 1650° C.: XVI. The surface-tension of some Haloge- 
nides of Sulphur, Phosphorus, Arsenic, Antimony and Bis- 
muthum”’. By Prof. Dr. F. M. Jarerr and Dr. Jun. Kann. 
(Communicated in the meetiug of June 24, 1916). 
§ 1. In the following paper the measurements of the surface- 
energy are described, which were made with the substances: 
sulphurmonochloride; — phosphorustrichloride; — phosphorustribromide ; 
phosphorustriiodide; arsenictrichloride; arsenictribromide; antimony- 
trichloride; bismuthumtrichloride; and bismuthumtribromide. In the 
‘ase of antimony-tribromide on heating already inmediately a decom- 
position was observed; the measurements were therefore no longer 
continued. The determination of the specific gravity of P/, appeared 
not to be possible with the desired accuracy owing to the too rapidly 
occurring decomposition of the substance under the influence of the 
water-vapour of the atmosphere. 
