248 Prof. P. J. Daniell on the 



of the above results. A small quantity of argon, present in 

 helium when a discharge is sent through a Geissler tube, may 

 be easily detected spectroscopically; but when some helium 

 is present in argon its quantity must be considerably greater 

 in order to give a distinct enough spectrum. 



With regard to the electronegative gases, gases in which 

 electrons lose their energy at every collision with the mole- 

 cules, the analogous considerations are probably far more 

 complicated. 



Petrograd, 

 Physical Institute of the University. 



XXII. The Coefficient of End- Correction. — Part II. By 

 P. J. Daniell, JB.A., Assistant Professor in Applied 

 Mathematics, The Mice Institute, Houston, Texas *. 



§ 1. TF an electrical current passes through a long cylin- 

 X drical tube of conducting material, and then out 

 into a large hemispherical volume of the same, the total 

 resistance is proportional to the total length of the tube plus 

 a certain multiple of the radius. This multiple is the 

 coefficient of end-correction which we require to find. 

 Bayleigh in his ' Theory of Sound ' found that 



•785 < this coefficient k < '845. 



In the previous paper with the same title the author assumed 

 the normal current at the open end to be of a form 



A + B(1- OT 2 ) + C(1-^ 2 )- 1 / 3 . 



Thus it was found that 



(1) if B is neglected, the approximate value of k is '82171 ; 



(2) considering B, the approximate value of k is '82168. 



Then the method shows that the real value of k < '8216^. 



In this paper the author states a method by which an 

 approximate value of k can be found which is less than the 

 real value. In fact 



'82141 < real value k. 



Thus k is confined between the narrow limits 



•82141 < k < -82168. 



The method by which Rayleigh found the lower limit 

 '785 for k, was to assume a value for the potential V at the 



* Communicated by the Author. 



