490 Dr. I.J. Schwatt on the 



cathode, and for copper cathode-aluminium anode are 

 shown. In the former case gas was evolved for a long 

 period, and absorption did not set in at all. In the latter, 

 absorption occurred after the passage of a few coulombs. 

 The probable explanation is that disintegration did not set 

 in at all in the first case, and hence there was no absorption, 

 whereas in the latter case disintegration, and therefore also 

 absorption, set in early in the experiment. 



Hiecke 8 concluded from some of his experiments that a 

 fraction of the atoms bombarding the cathode are absorbed. 

 He was unaware of the changes in the rate of absorption 

 that occur after a tube is rested, and neglected them. That 

 they are considerable is apparent from curves VIII., IX., 

 XXXV., and others in Hodgson's paper 4 . 



The apparatus used in the above experiments was obtained 

 by a. grant from the Research Fund of the University of 

 Bristol Colston Society. 



Physical Laboratory, 



University of Bristol. 



LVI. Note on the Expansion of a Function. 

 By I. J. Schwatt *. 



npo exp; 



ind 



(tan 1 x)p, -\<®<\y 



in powers of x. 



fx J go r 2*-i 



HoT^i^ 1 ^- • • • (1> 



tan \ 

 and 



Jo 1 + A ' 2 



l X go t 2k-1 <» 



Jo «=l AK — L a= i 



8 See par. 1, note 8. 4 See par. 1, note 4. 



* Communicated bv the Author. 



