CONTEMPORARY ADVANCES IN PHYSICS 



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of given kind depends on its speed; the greatest amount which (in 

 this particular chamber) a proton could ever produce, with its most 

 favorable speed, is indicated by the longest lines in {h), and one sees 

 that even these are definitely shorter than the lines in {a) due to 



^-- f'-^-'Tf^-fr' 



(a) 



ic) 



Fig. 6 — Three records of the ionization produced by individual particles in a 

 shallow ionization-chamber: (a) alpha-particles of nearly the same speed, (b) protons 

 of various speeds, (c) particles of several kinds which had been set into motion by 

 impacts of neutrons. The fogging along the base-lines is much fainter in the original 

 records than in these reproductions. (J. R. Dunning) 



