146, 147] 



Isothermals 



The graph expressing d log pb/dp as a function of v is therefore that given 

 in fig. 7. 



FIG. 7. 



The dotted part is admittedly conjectural, but it is very unlikely that it is 

 entirely misleading, for it is obvious enough that pi will increase steadily as p 

 increases. From this graph we can draw the graph of the values of T given 

 by equation (308), namely the values which cause dp/dv to vanish. The latter 

 graph is represented in fig. 8. 



T 



> v 



t r } 



Q 



FIG. 8. 



The only difficulty in drawing this figure lies in determining the form of 

 the graph near the point v = v at which T = 0. It is however obvious, from 

 the way in which p^ is calculated, that near to v = v , p b must be proportional 

 J, 9 



