325 
graphically in Fig. 1. C’ and C”’ are seen to be practically equal 
17500 
0 50 100 150 200 250 300 
Bie. 1. 
for the different degrees of dryness, while A’ (31° for ferrous sul- 
phate I) and A" differ and increase in magnitude with the quantity 
of moisture present in the salt.') The difference between the values 
of C’ and C”’ for different degrees of dryness is so small that it 
practically coincides with the limits of accuracy of the observations. 
On the present representation the temperature at which xy attains its 
1) For crystallized ferrous sulphate the line, according to Table I!, Comm. 122a 
of KAMERLINGH ONNES and PERRIER, is passing almost through the origin, 4’ being 
2° only. So, interposition of a small number of water molecules seems to increase 
A, of a great number to reduce it to a very small value. (Note added in the 
translation). : 
