122 



ILLINOIS STATE ACADEMY OF SCIENCE 



Central Scientific Company of Chicago, Illinois. The 

 simplified form of the ray track apparatus was made en- 

 tirely of glass, — of Pyrex glass. Fig. 1 shows a vertical 

 section through the axis of the compression chamber and 

 bulb, while Fig. 2 is a view from the top downward, as 

 the observer would view the apparatus. Several ray 

 tracks are indicated as issuing from the tip of the plug 



^ F*H S,.t . , 



Fig. 1 



Fig. 2 



P. In Fig 1 also are shown the electrical connections. 

 The main body of the apparatus was made of a 150 cc 

 Pyrex beaker, one being selected with a clear, smooth 

 bottom so that anything taking place within the chamber 

 could be seen easily and without distortion, the bottom 



