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BELL SYSTEM TECHNICAL JOURNAL 



from atoms of the gas. (The agent which bends them into curlicues is, 

 of course, a magnetic field applied to the whole of the Wilson chamber.) 

 Showers, then, comprise photons as well as charged particles. The 



450 



2 250 



<] P 



• "single" particles 

 o shower particles 

 '^ shower-producing particles 



50 100 150 200 250 300 350 400 450 500 



E| IN MEV 



Fig. 8 — Energy-losses per unit length of path (in Mev/cm) suffered by 94 cosmic-ray 

 particles in traveling through platinum. (Anderson and Neddermeyer) 



special value of Figs. 5 and 7 is, that they show the progressive 

 aggrandizement of showers as these pass onward through dense matter. 

 This is called "the multiplication of showers." Shower particles are 

 themselves capable of being shower -producing particles. One could not 

 tell from these figures whether the multiplication is due to the charged 

 particles or the photons, to either singly or to both. Here again the 



