862 Prof. Bragg and Mr. Glasson on a Want of 



It should be observed that some of the results thus shown 

 were obtained at different times, so that too much must not 

 be built upon a comparison between them ; only the relative 



Fie:. 6. 



•02 '04 '06 '08 



. Thickness of Copper Absorbing Screen in mm. 



positions of: the emergence and incidence curves of each 

 substance are sufficiently correct, and the form of each curve 

 as showing the homogeneity or otherwise of the various 

 radiations. One figure shows the emergence (E) and 



