356 Proceedings of the Royal Society of Edinburgh. [Sess. 
the magnetic units within the atom, viz. fixed radiating magnets with 
rotating units at the external poles. There is an objection to this arrange- 
ment, which is evident when we examine critically what is supposed to 
happen during chemical combination. On the near enough approach of 
the second atom the energy which is transformed during combination is 
entirely due to the swinging of the little magnet in the first atom, which 
is controlled by the magnetic force of the fixed magnets of the first atom 
alone, and therefore, in every case, no matter what the nature of the 
second atom was, or the momentum with which it approaches, or the 
strength of its magnetic field, the amount of energy transformed during 
the combination would be the same. Even if we supposed that the action 
is between two little magnets on the outer shell of the two atoms, the 
same is true, for on approaching each other both magnetic units will swing 
outwards, but only one, the one most weakly controlled, will rotate through 
180°, while the other will swing back to its old position. This would 
require us to suppose, to take an example, that if in the formation of 
potassium chloride and potassium bromide we imagine in each case that 
it is the little magnet on the potassium atom which swings through 180°, 
the heat of formation of the two salts would be the same. It is evident 
then that we must suppose some arrangement of our magnetic units which 
requires a magnetic unit in each atom to be swung permanently into a new 
position. If we imagine small magnets to be arranged in concentric circles 
round the nucleus, as shown in fig. 3, we would have a very stable 
arrangement which also would have no external magnetic polarity. If we 
now imagine two such atoms approaching, at that portion of the circles of 
each where they approach most nearly to each other two magnetic units 
could swing outwards, as shown in fig. 4. It is a matter of indifference 
whether they arrange themselves south to north or north to south, but 
in both atoms the magnetic units will swing through about 90°, and 
in each atom work would be done and energy dissipated as heat. It 
is difficult, however, on this assumption to explain valency. There seems 
no reason why atoms should not attach themselves all round the first atom 
until the outer shell of magnetic units is completely broken up. If, how- 
ever, we adopt the view that comparatively few magnetic units are in the 
outer shell, and those are the ones that take part in chemical change, then 
only the magnetic units in the outer shell could approach near enough to 
each other to swing into a new position of stability. We can suppose that 
a magnetic unit in the outer shell, attracted radially by the nucleus, and 
electrostatically repelled by two neighbouring magnetic electrons in the 
inner shell, and magnetically attracted by their north and south poles 
