1212 



and this is indeed not =0 for r = a, but no essential objection 

 in principle can be raised against this. It may, namely, be assumed 

 that the molecules will suddenly experience an attractive force 

 (proportional to 1 : r') at their entrance inside the sphere of attraction. 

 If o,iij _ p^ itself becomes = for r = a, which is the case on 

 our above assumption. 



Fontanivent, Autumn 1917. 



(To be continued). 



