( 613 ) 
Accordingly the question whether for a temperature somewhat 
; F é ; da ate 
higher than that for which for «, aa MRT —, there will be double 
Av AL 
intersection and then contact, or no intersection of the two curves, 
will depend on the fact whether the expression : 
; db\? 
2MRT ( =) 
da 
aa 
Vz 2a 
i MRT 
; da db 
or, since we have here — = MR] ae 
will be smaller or larger than 1. So for the case a,a, =d’, 
there is no longer any question of intersection above the temperature 
da 
dx 
db 
dx Tr 
MRT =S 
because then v, is twice as large as v,, and a,, must have conside- 
rably descended below this value, before there can be question of 
this. Just as VAN DER Waats derived (These Proc. June 1908) we 
get contact if v, = v,, and so 
(=) 
de 
zl. 
da 
a eN 
b 
It appears that the value of —, which belongs to the point of 
(bi 
contact (loc. cit. fig. 32) becomes equal to zero in this case, not 
because the denominator becomes infinite, but because the numerator 
becomes zero, 
