Forces between Atoms and Chemical Affinity. 787 



than forty this number may not be eight ; if this should prove 

 to be the case, the sum of the positive and negative valencies 

 for such elements would not be equal to eight. 



The union between two atoms exerting opposite valencies 

 might be expected to be firmer in general than that between 

 atoms exerting valencies of the same kind. For when they 

 are exerting valencies of the same sign, the electric doublets 

 which represent the forces between the atoms are arranged 



Fin-. 2. 



as in fig. 2 ; whereas when they are exerting valencies of 

 opposite signs they will be arranged as in fig. 3. It will be 



Fur. 3. 



©0 



seen that if the distances between the centres of the atoms 

 are the same in the two cases, the forces between the 

 doublets will be greater in the case represented by fig. 2 

 than in that represented by fig. 3, as the opposite poles of 

 the two, doublets are much nearer together in the first than 

 in the second case. 



If the forces between the atoms were sufficiently large to 

 drag the corpuscles out of the electropositive atom and heap 

 them on to the electronegative one, we see that after the 

 transference had taken place there would be no mobile 

 corpuscles left on the electropositive atom ; and as the 

 number of corpuscles in the outer ring of the electro- 

 negative element would be increased to eight, and eioht 

 forms a rigid ring, there would be no mobile corpuscles on 

 the electronegative atom either. 



When the corpuscles are transferred from one atom to 

 another there is a diminution in the number of tubes of 

 force, and if all the mobile corpuscles are removed from the 



