264 
MAJOR A. E. OXLEY ON THE INFLUENCE OF MOLECULAR 
with the case for benzophenone. In the case of water the diagram is as in fig. 3 and 
for p = \ atmosphere, is negative and L is positive. The m.p. is in this case 
located on the arc A'B' in the second quadrant. A similar case is that of pure iron as 
the temperature is raised through the critical point A 3 (see fig. 4). At A 3 , SV is 
negative and L is positive, while — is negative. 
Now 
L L 
Therefore > Vy which gives a shrinkage in iron on heating through the A 3 point at 
about 900° C. 
av=o 
Tlie application of the relation 
ap L “ L 
is interesting in connexion with some abnormalities of heats of recalescence in ferro¬ 
magnetic media. The change of volume dV, both expansion and contraction ; the 
absorption or evolution of heat of the amount L, depend solely upon the shape of the 
region of crystalline stability and its position relatively to the 3-, p axes. 
Thus nickel steel with no carbon and pure cobalt show no recalescence at the 
magnetic change points. In these cases L is very small and since and S- are finite, 
cS" 
— will 1 )e large (fig. 5). In other words, under the pressure of one atmosphere, the 
path of the crystallization curve cuts the line AB at a steep angle in the neighbourhood 
of the intersection of the fusion curve with the neutral line L = 0, 
