300 Proceedings of Royal Society of Edinburgh. 
t 
A 
A at 
118*25 
0*764 
1*00 
41*9 
117*10 
1*546 
2*16 
44*7 
116*20 
2*251 
305 
43*4 
115*24 
3*100 
4*01 
41*4 
114*43 
3*716 
4*82 
41-5 
Mean, 42*6 
When the temperatures and quantities of amorphous sulphur are 
plotted, the points are found to lie upon a straight line, which 
intersects the temperature axis at 1 19*25°. The depressions of the 
freezing points below this point (the freezing point of pure soluble 
sulphur) are therefore proportional to the amounts of the dissolved 
body. Raoulfs law thus expresses the relation, and the freezing 
point seems to be determined solely by the quantity of the dissolved 
amorphous sulphur. 
In the third column are given the depressions below 119*25°, 
and in the fourth the depressions which would be produced by 
32 gr., one atomic weight, of amorphous sulphur dissolved in 
100 gr. of soluble sulphur. The latter should be constant. 
The mean atomic depression is 42*6. Another series of four 
observations gave exactly the same mean result. Now, the 
molecular depression can be calculated by means of Van J t Hoffs 
formula, 
. 0*0198 T 2 
A m = , 
where T is the freezing point of the solvent in the absolute scale 
(119*25° + 273°), and q is the heat of fusion of the solvent (9*368). 
From these data A M = 325°. Dividing this by the atomic depres- 
sion, the quotient 7*6 represents the number of atoms in the 
molecule. Inasmuch as the quantities of amorphous sulphur are 
probably somewhat underestimated, and the atomic depression is 
therefore too large, we may take it that the molecule contains 
eight atoms. The equation for the change is thus 
S# (liquid) S 8 (amorphous). 
