240 



Dr. L. Vegard on the Electric 



dealing with the same subject, which I have published some 

 years ago. 



As these papers seem to have been overlooked by the 

 authors, I should like to state briefly some of my results. 



In a paper appearing in the Phil. Mag. for Oct. 1909 

 I published some experiments on absorption in oxygen and 

 hydrobromic acid, showing that the absorption was mainly a 

 function of the cathode-fall. As long as the cathode-fall teas 

 small the absorption teas very small indeed; but if in any way 

 — either by increase of current or diminution of pressure — the 

 cathode-fall was raised the absorption rapidly increased until 

 it reached a maximum of the order of the electrochemical 

 equivalent. 



It was concluded that£/j<? absorption took place at the cathode 

 and was closely connected with the disintegration of the cathode, 

 and to explain these results I put forward the hypothesis that 

 the absorption was produced by the rapidly moving positive 

 ions (positive rays) before the cathode. 



Further experiments were carried out at the Cavendish 

 Laboratory in 1909 on the absorption in oxygen, helium, and 

 hydrogen, and the results given in a paper which was put 

 to the care of i\\i\ Society of Science at Christiania, in 1910. 

 In this paper I introduced a distinction between two kinds 

 of absorption. One quite definite and lasting, which I called 

 the conservative absorption, and another which I called non- 

 conservative, and which is to designate a number of absorption 

 phenomena which may have various causes and essentially 

 depend on the state of the tube. 



When the bulb has been run for some time the conservative 

 absorption becomes definite and can for the same tube very 

 nearly be regarded as a single-valued function of current and 

 pressure. This function was studied, and it was found that 

 the absorption per coulomb was essentially dependent on the 

 cathode-fall in the way shown in my first paper, and set in 

 when the cathode-fall was raised above a critical value. 



For a cathode-fall which did not greatly exceed the 

 critical value O and a constant current, the absorption per 

 coulomb was found to be approximately given by the expression 



? -A(O-C ) (1) 



I also calculated the number (fi) of atoms absorbed per coulomb. 



In the table are given the values ^r, where N is the number 



2N' 



of molecules in a cubic centimetre ol 

 pressure and 0° C. 



gas at atmospheric 



