SOMR CONTF.MPOR.lRy .IIU\IXCl:S IX riiySICS ril .110 



rfl.iiii ilu- primary wavclcnutli are inore aluinil.ml ihan tlic allerfd 

 (luanta. whik- amonn the <inanta scattered at 13")° the modified ones 

 liavf the pritlominanee. Why tlie relative (-ommnnncss of ihc-^c \\\i< 

 kinds of Malleriiiif, of these two modes of iiiUr.iriinii liciwccii (|ii,irM.i 



I'ig. 9 — The modified and iinnicKlitied scattered rays, at various inclinations, recorded 



l)y the ionization-chamber method. The vertical line 7" represents the position 



calculatetl from {')) lor the modified ray. (A. H. Compton, Physical Revinv) 



and matter, should depend on the substance and on the angle 6 is a 

 deeper question than any we have considered. 



The recoiling electrf)ns also have been detected; and Figs. 10 and 1 1 . 

 which are photographs of the trails left by flying electrons as they 



