88 WHAT 18 LIFE 



in fertility. I know of no competitor which is as 

 yet even in sight. "^ 



Thus J. D. Main Smith : "It is the only existing the- 

 ory of the atom which is in conformity with the known 

 facts of atomic structure and spectrum analysis. It 

 must consequently be accepted that the atom of the 

 physicist and the chemist is a dynamic atom, and 

 theories based on static electrons must give place 

 to it, no matter how difficult the conception of the 

 dynamic atom may be for the mechanism of chemical 

 combination."^ 



It is true that to interpret the valency phenomena 

 of organic chemistry in terms of orbital electrons 

 at first sight offers difficulty. And obviously, if the 

 Bohr-Sommerfeld atom really gives the correct 

 picture of the atom, it eventually must make possible 

 the solution of all problems of valency. In a "Kelvin 

 Lecture," J. H. Jeans observed: "At present the 

 hydrogen atom and the positively-charged helium 

 atom are the only structures which are completely 

 understood, but there can be little doubt that in 

 time the method will unravel for us the secrets of 

 even the most complicated of atomic and molec- 

 ular structures."* 



Perhaps no fact of science has been more tlior- 



' The Electron, second edition, 228. 

 ' Chemistry and Atomic Structure, 163. 

 « Nature, March 7, 1925. 



