Experiments on Delta Bays. 



;.3i 



the electrodes. It was clear that the desired conditions were 

 attained, in that all delta rays were produced within A and 

 that no disturbance was introduced by the /3 and 7 rays 

 emitted by the active deposit. 



6. If there were no air in the vessel and if none of the 

 delta rays were reflected at the electrode, the relation of the 

 current to the potential difference between A and D would 

 give directly the distribution of the velocities of the rays. 

 When the potential difference is zero, all the rays emerging 

 through the hole strike D ; when the potential of A is V 

 above that of D, all the delta rays having an initial velocity 

 less than Y will be prevented from reaching D. Accordingly, 

 if iy is the current flowing to D corresponding to the poten- 

 tial V, i Y /i should be the proportion of the raj^s having a 

 velocity greater than V. When V is very great i Y should 

 be zero, and it should be zero also for all values of V when 

 a magnetic field of sufficient strength is established in a 

 direction parallel to the surface of D, so as to prevent any 

 of the rays from A reaching D. The values of the current 

 when Y is negative do not concern us ; they merely indicate 

 how many electrons can be dragged from inside A by an 

 external field. 



Fig. 2. 

 A & D both Aluminium. 



. Fipr. 3. 



Aluminium; D, Soot. 



* 



Figs. 2 and 3 show the nature of the curves determined 

 experimentally. In fig. 2 both A and D were of aluminium; 



