872 Messrs. Gray and Wilson on the Heterogeneity of 



rays were homogeneous we should get a curve somewhat 

 similar to that shown, on account of: the necessarily finite 

 size of the holes and P. The following test of the 



Fisr. 



4.000 6.000 



H/y //v G/wss Cm. 



homogeneity of the rays was therefore applied. A sheet of 

 aluminium of known thickness was placed in the path ot 

 the rays just underneath the electroscope, which was about 

 2 mm. above the holeP, and the experiment repeated. Now 

 if the rays are heterogeneous, those which enter the electro- 

 scope with the higher magnetic fields should be less easily 

 absorbed than those which enter with the lower. lhe 

 maximum point should therefore move to the higher fields 

 when sheets of aluminium are placed under the electroscope. 

 That this is the case is shown unmistakably by the curves 

 of fie 2, a, b, c, d, e, which are plotted from the results 

 obtained with 0, '067, -245, '489, '731 mm ot alummmm 

 respectively under the electroscope. If, on the other hand, 



