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Physics. - "On the measurement of very low temperatures. XXII. 

 The thermo-element gold-silver <ii liquid hydrogen temperatures." 

 By 11. Kaaierlingh Onnes and .1. Clay. (Communication 

 X". J07 ; ' from the physical laboratory at Leiden). 



(Communicated in the meeting of Ma) 30, 1908). 



The thermo-elemenl gold-silver of which, when one of the limits 

 is kept at . tlic electromotive force al ordinary temperature is 

 about zero, shows ;it lower temperatures a more and more rapid 

 increase of electromotive force 1 ). 



A calibration with the hydrogen thermometer has shown that al 

 the temperatures which can be reached with liquid and solid hydrogen 

 the increase of the electromotive force of this thermo-elemenl per 

 degree becomes large enough to render ii suitable for temperature 

 determinations in the area under consideration, while al the tempe- 

 ratures far below the melting point of hydrogen for the determination 

 of which the helium thermometer must be used for the calibration 

 instead of the hydrogen thermometer the sensibility of the instrument 

 will be greater still. 



The following table may serve to make thi> clear. 



] ) Coinp. the measurements of J. Clay in his thesis for the doctorate and in 

 Gomru. no. 107c/ from the Physical Laboratory at Leiden. 



