r.»ll] oil ('hemical Change at Low I'emperatnres. 



Sea/ after condensing oxygen 



•201 



to M^CIeod gauge 



Seal after O.fillinq 



to mercurg pump 

 also vacuum tube 

 nith liquid ofu/gen 



to 3'way cock &. 

 B mercury pump s. charcoal 

 as aboye 



Fig. 5. 



