PHYSICS 



considerations have been shown to apply to a 

 number of other elements, and they probably 

 account for nearly all the deviations from whole 

 numbers in the atomic weights. They will not, 

 however, account for the atomic weight 1-008 

 of hydrogen, which has been carefully examined 

 and found not to consist of a mixture of isotopes. 

 If, however, the heavier elements are formed from 

 hydrogen with evolution of energy we should 

 expect the atomic weight of hydrogen to be greater 

 than unity. One of the theorems which the 

 recent advances in theoretical physics have given 

 us is that the mass of any material system is 

 proportional to the total energy of the system. 

 The fact that the only positively-charged frag- 

 ments which are ejected from the nuclei of the 

 radioactive atoms are helium (of mass 4 and charge 

 2) suggests that the main substructure in the 

 various nuclei is a helium nucleus formed by the 

 combination of 4 hydrogen nuclei and 2 electrons. 

 In our view the fact that the mass of this is less 

 than four times 1-008, minus the mass of the 

 negative electrons, merely means that the substruc- 

 ture is formed with evolution of energy. This 

 energy will be measured by the difference between 

 the two sides of the equation between the respec- 

 tive masses involved in the reaction. A similar 

 correction for the mass of the evolved energy 

 should strictly be made in writing the equation 



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