182 



international atmospheres, the international atmosphere being taken 

 equal to a mercury column of 75.9488 ciïis at Leiden. 



Above ^k the following point was measured 



The critical quantities derived from the above figures are as follows 



The deviation of Bülle's result from ours mav, as we think, be 

 partly explained from his having used a resistance-thermometer which 

 was only calibrated by means of hydrogen- and oxygen-temperatures 

 and on the other hand perhaps also from the arrangement of his 

 apparatus. Possibly owing to the rapidity with which he had to 

 conduct the experiment the flask in which the hydrogen was com- 

 pressed had not yet assumed the temperature of the resistance- 

 thermometer when the measurement was made. 



§ 3. Estimation of the critical density. 



By means of the above value of the critical temperature, of the 



