TRAVERSED BY CATHODE RAYS. 
77 
4. Lenard’s results obtained by fluoroscopic methods on the absorption of cathode 
rays are confirmed by a study of the ionization these rays produce in gases. 
5. When cathode rays of a given strength are passed through a gas, the number 
of ions produced in 1 cub. centim. depends only upon the density of the gas, and is 
independent of its chemical composition. 
6. With rays of constant intensity the ionization in any particular gas varies 
directly with the pressure to which it is subjected. 
7. The relative ionizations produced by cathode rays of constant intensity in air, 
oxygen, nitrogen, carbon dioxide, hydrogen, and nitrous oxide, at the same pressure, 
are expressed by the numbers which represent their densities. 
8. With cathode rays, just as with llontgen rays, the number of ions produced in 
a gas bears a definite ratio to the amount of the radiant energy absorbed. 
I gladly avail myself of this opportunity to record my grateful sense of the never 
failing encouragement and assistance received from Professor J. J. Ti-iomsov. 
