Electric Deviation of Rays from Radium. 



170 



the spontaneous ionization of air. The gold-leaf system was 

 insulated inside the vessel by a sulphur bead C, and could be 



Fig. 1 B„ 



Outf)ouj of Hydroger 



charged by means of a movable wire D, which was afterwards 

 earthed. The rate of movement of the gold-leaf was observed 

 by means of a microscope through small mica windows in the 



testing vessel. 



In order to increase the ionization in the testing vessel. 

 the rays passed through 20 to 25 slits of equal width, placed 

 side by side. This was arranged by cutting grooves at regular 

 intervals in side-plates into which brass plates were slipped. 

 A cross section of the system of metal plates and air-spaces 

 is shown in fig. IB. 



The width of the slit varied in different experiments between 

 '042 and '1 cm. 



The magnetic field was applied perpendicular to the plaint 

 of the paper and parallel to the plane of the slits. 



The testing vessel and system of plates were waxed to a lead 



N 2 



