The α Rays of Radium

Abstract

IN Mr. Soddy's article on radio-activity in your issue of January 28, he remarks as peculiar the fact that the α rays possess the “property of being more difficult to deviate for any given strength of field the greater the distance of air traversed.” Surely if these rays consist of positively charged material particles, their velocity must diminish in proportion to the distance of air traversed, and hence their magnetic effect, and consequently their deviability, must diminish also.