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the sun’s heat, light, or attraction. What other influence 
then can the sun exert on the earth ? 
The analogy between the magnetism produced in a spin- 
ning top by the inductive action of a distant body charged 
with electricity, and the magnetism in the rotating earth, 
probably caused by the influence of the sun, which influence 
is not its mass or heat, seems to me to suggest what the 
influence which the sun exerts is. If the sun were charged 
with negative electricity, it seems to me to follow, from what 
the experiments I have described establish, that its inductive 
effect on the earth would be to render it magnetic, the 
poles being as they are. 
The only other way in which the sun could act to produce 
or influence terrestrial magnetism would be by its own 
magnetism. If the sun is a magnet, it would magnetise the 
earth. If this is the cause the sun’s poles must be opposite 
to those of the earth. Now, it follows that such a condition 
of magnetism would or might, if its materials are magnetic, 
be caused by the rotation of the sun under the inductive 
action of the earth and planets in exactly the same way as 
that caused in the earth by the inductive action of the sun. 
As the direction of rotation is the same in both bodies, and 
the electricities of the opposite kind, the magnetism would 
be of the opposite kind also. So that on this hypothesis it 
is probable the sun would act by both causes. 
When I first worked out this idea, I was not aware that 
anything like it had been suggested before ; but Mr. 
Baxendell, after having seen my experiments, noticed a 
review of a book on terrestrial magnetism, to which he 
kindly called my attention. The author, without making 
any assumption with regard to the electrical condition of 
the sun, assumes it to act on the earth’s magnetism precisely 
as it would under the conditions I have described; and he 
then proceeds to consider, not only the general features of 
the earth’s magnetism, but all its details — and this in a 
