(Belongs to Proceedings of the meeting 

 of Saturday October 81, l ( -">*>. 



H. KAMERLINGH ONNES and C. BRAAK. 'On the measurement of very- 

 low temperatures XXI. On the standardizing of temperatures by means 

 of boiling points of pure substances. The determination of the vapour 

 pressure of oxygen at three temperatures." 



Proceedings Royal Acad. Amsterdam. Vol. XI. 



