CONTEMPORARY ADVANCES IN PHYSICS 



691 



the method which they invented is so extremely different from any of 

 those by which the foregoing data were acquired, that in this place I 

 cannot give anything like a full account of it. Briefly: the gas is in a 

 metal cylinder having a filament running along its axis and metal plates 



lOOr 



\J VOLT 



lOOr 



He 



VvOLT 



100 



^^/ 



A 



CO2 



/ 



/ 



/ 



/volt 



Fig. 13 — Broken curves: cross-sections by Ramsauer's method. Continuous 

 curves: cross-sections for scattering at angles near 90°, by Kollath's method (see 

 text). {Annalen d. Physik.) 



which almost close its ends. One of these end-plates is raised to a 

 potential some fifty or a hundred volts above the filament; and so 

 dense is the electron-current pouring out of this latter, that almost the 

 whole of the gas in the cylinder becomes violently ionized and shining, 



