222 



Mr Chree, On some experiments on 



[June 1, 



(3) A Linkage for describing Lemniscates and other Inverses 

 of Conic Sections. By R. S. Cole. 



(4) Some experiments on liquid electrodes in vacuum tubes. 

 By C. Chree, M.A., Fellow of King's College. 



The experiments discussed in this paper were undertaken 

 at the suggestion of Professor J. J. Thomson, in order to throw 

 further light on the nature of the electric discharge in a vacuum 

 tube with liquid electrodes. To render the work intelligible it 

 is necessary to give a brief sketch of the general nature of the 

 discharge at low gaseous pressures, and to mention certain results 

 of previous observers and certain of their theoretical conclusions. 



At low pressures the phenomena at the cathode — or electrode 

 to which the positive current travels in the tube — are the most 

 striking, so that it is the most convenient point of departure. 

 The phenomena ordinarily observed between the electrodes when 

 not too near together are as follows : — 



(A) a thin luminous envelope covering the cathode, 



(B) a much thicker, but still except at very low pressures, 

 short dark space, 



(C) a bright, usually blue, space of considerable length, 



(D) a second dark space, 



(E) a more or less luminous interval extending to the anode. 



There is unfortunately no universally accepted English termi- 

 nology for these spaces. The following table shows some of the 

 terms most commonly used in English, and also the ordinary 

 German terminology. 



Table I. 



