( 612 ) 
detached, is entirely dependent on the fact whether the point 
: Ne 
= 2,,v =, lies outside or inside — = 0 for the temperature con- 
av 
sidered, as appears clearly from the figs. 8 and 9. Now as we saw 
BPN ata 
before the point where EE O intersects the line «=a, is deter- 
v 
mined by : 
2a 
MRT 
Fig. 8. 
