302 Mr Willows, On the distance between the striae in the positive 



Diophantine Inequalities. By G. B. Mathews, M.A., F.R.S. 

 [Bead 5 March 1900.] 

 v. Transactions, Vol. xix. Part I. 



On the distance betiveen the striae in the positive column and 

 other phenomena connected with the discharge. By R. S. Willows, 

 B.A., B.Sc, Trinity College, Cambridge; 1851 Exhibition Science 

 Scholar. [With Plate XIII] 



[Read 5 March 1900.] 



1. The experiments described in the following paper were 

 undertaken for the purpose of examining the manner in which 

 the distance between the striae in the positive column varied 

 when the pressure, current or other conditions were altered. 



Although the positive column bears a much more important 

 relation to the discharge than the phenomena connected with 

 the kathode, the latter being merely local effects, yet, owing 

 to the variety and importance of the effects connected with 

 kathode, Lenard and Rontgen rays, measurements relating to 

 the former have been relatively few. Thus, although it has been 

 frequently noticed that a decrease in pressure causes an increase 

 in distance between the striae, the only measurements we have 

 on the subject appear to be those of Goldstein 1 . If d is the 

 distance between two striations, and p is the density of the gas, 

 then for the same gas Goldstein found that d varies as p~ n where 

 n is somewhat less than unity. He also found that if d be 

 measured for the same two pressures in a large number of tubes 

 of different diameters, then the ratio of the two values is the 

 same for all tubes provided the striae reach nearly to the sides of 

 the tube. 



As far as I have been able to learn, no one has measured the 

 influence of current on the distance between the striae ; De la Rue 

 and Muller 2 observed that, starting with an intensity of current 

 giving steady striae, an increase in current produced unsteadiness 

 followed afterwards, as the current was further increased, by 

 a second steady state. This was repeated as the current was still 

 further increased. In another paper 3 they remark that " The 



1 Wied. Annal. 15, p. 277. 1882. 



2 Comp. Rend. 86, p. 1072. 1878. 



3 Phil. Trans. Vol. 169, pp. 90 and 118. 1878. 



