870 Dr. J. VV. Xieholson on a Structural 



behave as a monatomie gas, as there is every reason to suppose 

 that it would if the experiment were possible. 



Many suggestions could be made as to the probable nature 

 of a compound of this kind. For example, if an element 

 consisted of a compound of nebulium and protofluorine, 

 it might have an atom made up of two coplanar rings of 

 four and five electrons respectively, and two positive nuclei. 

 The essential feature is that these two nuclei should not 

 coalesce into one. The separate elements are there in a 

 sense, but not in the chemical sense, in which the two 

 elements would exist side by side as separate units, held 

 together perhaps by the transfer of an electron from one to 

 the other. 



It is needless to dwell at any length upon the question of 

 energy. The knowledge that an immense amount of energy 

 is liberated in radioactive transformations, and that their 

 rate of progress is apparently quite independent of external 

 conditions, such as temperature, which influence ordinary 

 chemical action, is sufficient to indicate the difference be- 

 tween the two types of " compound." When expressions like 

 "compound" and "protyle^are used, it is on account of 

 their convenience, and their limitations of meaning require 

 emphasis. 



Atomic Weight. 



The weight of an atom, always determined from its inertia, 

 may be regarded as the sum of the inertias of all its positive 

 and negative charges. If the positive charges have a much 

 smaller radius, their inertia will greatly overweigh that of 

 the electrons, and we may neglect the latter for the present. 

 The motions to which a nucleus is subject will always be 

 slow in comparison with the velocity of light. Let a be its 

 radius, and e the charge on an electron. If there are n 

 electrons in a neutral atom of a primary simple substance, 

 the positive charge is ne, and the inertia will be proportional 

 to n 2 e 2 ja by the usual formula for slow motions. 



If the positive electricity has a uniform volume density, 

 its volume is proportional to ne, and therefore a to ri*. 



Thus the inertia is proportional to ii$. That of a compound 

 atom containing several nuclei associated with rings of 

 electrons will be proportional to 



Assuming that the hydrogen atom has three electrons, the 



