568 



§ 6. The temperature-coefficients of the .specific siirface-energj/ 

 of the molten alcaU-haloyenldes. 



During tliese measurements, it became clear, that the siiape of 

 the curves, which illustrated the dependence of •/ and t, was in 

 most cases much nearer to that of strai^iht lines, than was the 

 case with most of the hitherto investigated organic liijuids. However 

 it must be remarked, that notwithstanding this, also in the case of 

 molten salts, the x-^curves could evidentlv belong to every one of 

 the three formerly discerned possible types, while in the case of 

 occurring dissociation a more rapid bending towards the temperature- 

 axis could be stated, just as in the analogous cases formerly studied. 

 Because of the nuich greater xalucs of the maximum-pressures 

 however in the here studied cases, those deviations from straight 

 lines come much less to the foreground. As a consequence, in thirty 

 cases of the about forty investigated salts, the dependence of / and 

 t could be expressed with sufficient accuracy by linear expressions; 

 for the remaining cases a quadratic expression in t with three con- 

 stants appeared to be adapted to this purpose to a really sufficient 

 degree. 



If t, is the nieltinypoint of the salt, then /, above this melting- 

 point, can be calculated from an equation of the form: 



X, = a — h{t — t..) -\-c{t — t,y, 

 in which a corresponds to the value of yj ^^t the meltingpoint. In 

 the following table the corresponding values of t,, a, b and c for 

 every one of the investigated halogenides are resumed : 



