of Hydrogen and some other Gases. 1^25 



diamagnetic susceptibility is considered to be independent 

 of temperature, we can get by multiplying the density of 

 the gas at any temperature and pressure into the specific 

 susceptibility above obtained, the volume susceptibility of 

 the gas at that temperature and pressure ; thus we get as the 

 volume susceptibility of carbon dioxide at 20° 0. and 760 mm. 

 pressure, 



« CO2 =-0-00077 9 xl0- 6 . 



The same consideration is used in the calculation of the 

 susceptibilities of the diamagnetic gases investigated in the 

 present research. 



The value of the specific susceptibility of carbon dioxide 

 obtained above is in fair agreement with the value 



Xoo = -0-42 X 10-« 



for the solid carbon dioxide obtained by Mr. T. Ishiwara 

 mentioned above. This sho ws that the specific susceptibilities 

 of carbon dioxide in the solid and gaseous states are almost 

 equal to each other. Putting for the moment this delicate 

 question of magnitude out of consideration, the close agree- 

 ment of these determinations seems to give strong confirm- 

 ation of the conclusion that the value obtained in the present 

 experiment for the gaseous carbon dioxide is not far from 

 the true value. At least we can assert that the magnetism 

 of carbon dioxide is diamagnetic, contrary to all previous 

 determinations. The paramagnetic result of the gaseous 

 carbon dioxide obtained by the previous investigators comes 

 probably from the impurity of the gas examined, such as a 

 trace of air mixed with the gas. 



Of the three sets of measurements quoted above, the last 

 one was made by a method which was in some respects 

 different from the other two. The method employed was 

 the null-method described in the last section. 



Namely, we measure the force / in terms of the volume 

 of water which is to be supplied or to be taken out of the 

 vessel hanging from the arm of the balance, in order to 

 bring the measuring tube to the initial position against the 

 magnetic force, or which is equivalent, to bring the deflexion 

 of the mirror to its initial reading on the scale. The volume 

 of water can be read from the volume of mercury thread in 

 the capillary tube. 



The following table contains the data of the measurement 

 for carbon dioxide by means of the null-method. Here r is 

 the reading of the head of the mercury thread in the capillary 



