759 



This qiieslion whicli is of fundamental importance for all absolute 

 pressure measurcnienl, cannot be considered as decided as yet. Nor 

 can our experiments at this moment give a decision, because we 

 have not yet been able to compare one of our pressure balances 

 directly w^ith an open manometer with transmission for sufficiently 

 high pressures (60 to 100 atm.). The indirect comparison obtained 

 by the very close agreement of our hydrogen-isotherm with that of 

 ScHAT-KwiJK, seems to point in the same direction as Wauner's 

 experiments, that namely actually effective and real area coincide. 

 Nevertheless a direct comparison remains, of course, a matter of 

 the highest importance for all our measurements and we greatly 

 hope, therefore, to be able to carry out a comparison before long. 



In what precedes we have discussed the principle of Schaffer 

 and Budenberg's pressure balances. We should now discuss for a 

 moment the execution of it in practice. For the lower pressures — 

 up to 250 atni. — this is very simple indeed. The cylindre A (fig. 2) 

 rests on a heavy cast tripod, whicli again is supported on a stand, 



c*=i 



O Kr 



Miiiiililiiin 



F 



4D 



Fig. 2. 

 Proceedings Royal Acad. Amsterdam. Vol. XVI. 



£^Z1. 



49 



