403 
‚Cu 
Although the values of 5, Are nol great, and generally smaller 
t ; 
than the normal value of 2.24 Erg per degree, they are however 
in all cases appreciably greater than such as occurred in the case 
of the inorganic molten salts; these, values here point in every 
respect to close analogy with the behaviour of organie liquids. 
Specific Surface-Energy 
x in Erg per cm”. 
70 
60 
50 
40 
JO 
Temperature - 
20 
“$0°-70°*10° 30° 50° 70° 90° 110°130° 150° 110" 90" 210" 230°250° 270° 290°310" 530°350°310°I90 40430 950 
Fig.1. | 
Doubtless the influence of the much lower boiling- and melting- 
temperatures, which are typical for these substances in comparison 
with the salts mentioned, makes itself felt here. 
As for the mutual situation of the y-/-curves (fig. 1), this appears 
to be quite regular, just as in the case of the alcali-halogenides, 
but just a the reverse direction, because at the same temperature, 7 
appears to increase with the atomic weight of the element combined 
with the halogen. A comparison of the y-t-ecurves of PCI, AsCl,, 
SbCl, and BiCl, on one side, and of PBr,, AsBr, and BiBr, on 
the other side, shows this immediately. It is remarkable however, 
that the same is the case here for the halogens: if the y-f-curves 
of PCI. PBr, and PI, are compared with each other, and also 
those of AsC/, and 4AsBr,, and of AiCl, and BiBr,, — it appears, 
that at the same temperatures the values of y are the greater, as the 
atomic weight of the halogen increases; i.e. just in the reverse 
direction as formerly was found in the case of the halogenides of the 
alcali-metals *). It is very probable that the cause of this striking 
deviation must be attributed to the much less pronounced contrast 
in electrochemical character, which the metalloids P, As and Sd 
show in comparison with the halogens, in comparison with that of 
the strongly electropositive a/cali-metals against those same halogens, 
1) I. M. JAEGER, These Proceedings 17. 568, 570. (1914). 
26* 
