TH R 



AMERICAN JOURNAL OF SCIENCE 



[FOURTH SERIES. ] 



Aet XLIX—A Theory to Explain the Stratification of th< 



Mectmc Discharge in Geissler Tubes ; by H. V. Gill' S J 

 (With Plates IV, V.) 



< In the following paper it is proposed to put forward as 

 simply as possible certain ideas regarding the cause of the strati- 

 fications seen when a discharge of electricity takes place in a 

 Geissler tube, and to describe some experiments which have 

 been made to test the value of these ideas. 



The stratified discharge is without doubt the most striking 

 phenomenon presented in the case of an electric disci 

 through a Geissler tube, and has naturally attracted the atl 

 tion of many scientists. Though, however, a vast amount of 

 time and trouble has been expended on expensive researcl 

 to the true cause of this curious and beautiful phenomenon, it 

 must be said that no theory has, up to this, been accepted as 

 satisfactory. As the question is one of great interesl and 

 importance, any contribution, however small, towards the solu- 

 tion of the mystery is of value, and hence it is deemed advisable 

 to present the following paper. 



In the first place, it will be useful to consider the electric 

 spark under normal conditions, especially with reference to 

 such of its mechanical effects as will help to throw some light 

 on the theory we are about to develop, since those who 1 

 devoted special attention to this point are all oi opinion that 

 the discharge in a rarefied gas is in no way different from the 

 discharge in air under ordinary conditions of grease 



*" The striations are only clearly marked within somewhal narrow lim 

 sure. But it is in accordance with the conclusion which all who h . the 



spark have arrived at— that there is complete continuity between the bi 

 defined spark which occurs at high pressures and the diffused glow 



Am. Jour. Sci.— Fourth Series, Vol. V, No. 30. — Ji h 



21 



