34 EFFECTS OF /3-RAYS OF DIFFERENT VELOCITIES 



ing this slit passed on through a distance of 2 cm. and impinged at 

 A upon a glass plate on which the eggs were spread. In the presence 

 of a magnetic field a slow ray, travelling in a course having a small 

 radius of curvature, would strike the glass plate at C while a fast 



Fig. 1. Diagram of apparatus for exposing Nereis eggs to homogeneous groups 

 of /3-rays of different velocities. 



ray travelling more nearly in a straight Hne would strike at B nearer 

 to A. Fig. 2 is a photographic record of the course of the direct 

 and deflected beam. 



Two procedures were employed to expose eggs to beams of rays 

 of different velocities. In one the magnetic field, H, was kept con- 



