Ice and its Natural History 



247 



represents the volume of pure ice at t, the salt being inert; 

 v, w and c have the same signification as in Table I. 

 H '(= Vv) represents the volume of pure ice included in U. 

 It will be seen that H, the volume of real ice present at /, 

 suffers a sudden diminution at 21 72, and then continues 



to diminish, at first slowly, and then at an increasing rate, 

 until liquefaction is complete. 



In Fig. I, curve B represents the variation of apparent 

 volume U with temperature /, the salt being active ; while 



