CONTEMPORARY ADVANCES IN PHYSICS 



213 



of one particle having a notable curvature and displaying an ionization 

 six times as great as that attributable to an electron; they inferred a 

 "mass 130," i.e. a rest-mass one hundred and thirty times as great as 

 that of an electron. Neddermeyer and Anderson transposed the 

 bottommost counter into the very centre of the cloud-chamber itself, 



2 1800 



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 Hp IN GAUSS-CENTIMETERS 



10 II 12 13 



XI06 



Fig. 13 — Relation between energy and i7p-value for electrons (of either sign) 

 and protons. (Anderson) 



and there it appears in Fig. 14, neatly intersected by the course of a 

 particle which above it made a track lightly curved and thinly studded 

 with droplets, and beneath it made a track sharply curved and densely 

 congested. Comparing ionization with curvature along the track 

 above and the track below, they found 240 to be a satisfactory ratio 



