SYMPOSIUM OX RADIOACTIVITY. 55 



amount of this intermolecular force is, but if it could be converted 

 into the energy- of moving masses, it would probably account for 

 the forces which seem to be involved in temporary stars. 



Similarly it seems to me that we ought to take account of such 

 possibility in our theories of cosmogony. We endeavor to account 

 for the momentum and energy' we now find in our solar system 

 and in stellar systems purely on the basis of masses of matter. 

 If it shall ultimately be shown that conditions may arise which 

 release the immense amount of energy in every molecule, it might 

 assist in our understanding of the processes of cosmogony. 



Finally, the tests thus far of the amount of helium in the 

 earth's crust have indicated, on the assumption that all the helium 

 has been produced from radium, an almost over-abundant 

 amount of radio-active elements to account for the observ^ed heat 

 within the earth. The accepted view of the maintenance of the 

 sun's heat is that it is due to the contraction of a gaseous body 

 at a rate of about three hundred feet in diameter per annum. 

 While this theory is in accordance with the laws of gaseous bodies 

 and is also in agreement with the views of many as to the evolu- 

 tion of the solar system, nevertheless if the amount of radium in 

 the sun is in proportion to that on the earth, as inferred from the 

 abundance of helium in the earth, no doubt the supply of radium 

 would fully account for the maintenance of the heat of our sun. 



III. RADIOCHEMISTRY. 



By William A. Noyes. 

 University of Illinois, Urbana. 

 (Abstract.) 

 While radiochemistry as a distinct branch of science has devel- 

 oped almost exclusively during the last decade, the beginnings 

 which led to this development go back more than a century. 



Toward the close of the 18th century Cavendish, by mixing air 

 with oxygen, and subjecting the mixture to the action of electric 

 sparks from a friction machine found, after a tedious experi- 

 ment, that 1 120 of the volume of nitrogen, which he used, could 

 not be converted by this method into oxides of nitrogen. He 

 had in realit}^ discovered argon, though it was a centur}' later 

 before the discovery was recognized. In 1868 Lockyer discovered 

 helium by the spectroscope in the sun. Both discoveries fore- 

 shadow the discovery of the noble gases by Rayleigh and Ramsay, 

 and these in turn prepared the way for the recognition of helium 



