The Evolution of the Sciences 



perhaps at the same time to sodium, while the 

 emanation, receiving an even smaller impulse 

 than in the last case, can be degraded only to the 

 state of argon. Possibly the carbon resulted, by 

 some analogous process, from the disintegration 

 of thorium, an element of the same family, but of 

 twenty times greater atomic weight. 



We may hence say that the a, /3 and y rays, this 

 powerful artillery of the radio-active substances, 

 act on so-called elements like shells on an armour 

 plate. The energy expends itself on the shell 

 as well as on the obstacle, with the result that in 

 proportion as the damage to the plate is great the 

 shell suffers little injury. 



Such an argument, as Ramsay himself admits, 

 can only be considered as a first and very rough 

 approximation, but it is the only general idea 

 which at present embraces the new facts. One 

 thing, however, is certain. Our present idea of 

 elements is being profoundly modified. We are 

 certain that transmutation is no fable, because 

 we have seen helium being born under our very 

 eyes, and we have very strong reasons for believ- 

 ing that other elements equally well defined 

 neon, argon and lithium can also come into 



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