Production of Cathode Particles by Rontgen Radiations. 321 



was finally absorbed completely in a thick brass disk E 

 which served as electrode. The cathode particles which 

 emerged from E were absorbed by a layer of paper gummed 

 on the surface of E, and so contributed nothing to the 

 ionization in the region ER. 



Another portion of the radiation, travelling at right angles 

 to the plane of the paper, entered an electroscope (to be 

 referred to as the primary electroscope) which served to 

 standardize the amount of homogeneous radiation emitted by 

 the radiator. 



As the quality of the homogeneous radiation is unaffected 

 by small variations in the bulb, and as the quantity of radiation 

 entering the chamber A is always the same fraction of that 

 entering the primary electroscope, no discordance in the 

 results can arise from slio-ht variations in the bulb. 



Apparatus. 



A cylindrical brass ionization vessel was constructed with 

 an internal diameter of 11 cms. (fig. 2). A circular opening, 



Fier. 2. 



to h ^, 



C*l»vto.s.l. tvbc, 

 &»!-» JrHj inlets 



7 cms. in diameter, was made in the bottom, and a piece of 

 copper gauze was fitted into this opening and carefully 

 soldered round the edges so as to be quite flush with the 

 bottom of the vessel. The details of this arrangement are 

 shown in fig. 3. A cap CO was then cast in brass and 





Fig. 3. 



SPoivcKf'ven.S 



S3\d 



turned down to fit tightly over the bottom BB. The cap 

 was made with a circular opening of the same size as that in 

 BB. A sheet of thin parchment w<is used to cover the Cu 

 gauze : its weight was equivalent to that of '005 mm. of Al. 



