1905.] 



on the Structure of the Atom. 



61 



provided it carried the same charge. The other part of the force, 

 which we shall call the M part, is independent of the charge on B, but 

 depends essentially on its structure ; this part of the force would be 

 entirely altered, if we replaced B by an atom of a different kind. 



The question now arises. What part do these two types of force play 

 in determining the nature of the molecule ? Is the stability determined 

 by forces of the E or of the M type ? 



The E forces depend on the charges carried by the atom, so that 

 in those compounds in which stability is due to the E forces, the 



Fig. 8. 



atoms must be charged. We are thus confronted with the question, 

 Are the atoms in a molecule charged with electricity, or are they elec- 

 trically neutral ? Thus, to take a delinite case, in the molecule of 

 marsh gas, which we picture as a carbon atom at the centre of a tetra- 

 hedron with the four hydrogen atoms at the corners, are the hydrogen 

 atoms charged with equal quantities of negative electricity, the carbon 

 atom having a four-fold charge of positive, or are both carbon and 

 hydrogen atoms uncharged ? It is difficult to get direct evidence on 

 this point, since the molecule as a whole is neutral on either supposi- 



