fined to actual experience obtained on our own planet and
in relation only to that planet. But philosophy is not satisfied with
such a narrow and limited outlook, but drawing its conclusions from
actual experience on our own planet, in accordance with the rules of
philosophy, it seeks to apply such experience gained to the explanation
of phenomena of other planets which also revolve round the sun.

By such reasoning we learn that all the other planets have North and
South geographical poles like our earth, although we have never actually
trodden on those planets, or discovered the poles. We also learn that
Mars possesses climatic conditions probably similar to our own earth, as
there are certain changes on the surface around the poles, which by
analogy we assume to be caused by increase and decrease of snow during
the Arctic winter and summer of Mars respectively.

The analogy between our earth and the other planets is very full and
complete, as the following results show. Our earth has an atmosphere, so
have all the rest of the planets. The earth revolves on its axis from
West to East, so do all the rest. The earth possesses two geographical
poles, so do all the other planets. The earth revolves round the sun in
an orbit of elliptic form, so do the other planets. The earth fulfils
all the laws of motion as given by Newton, and all the other planets do
the same. The earth fulfils all Kepler's laws, and this is also true of
all the others. Indeed, the only difference apparently that exists at
present between the earth and all the other planets is, that our earth
is a magnet, while at present it is not conceded that all the others are
magnets.

Now such a conclusion I venture to say is altogether opposed to every
rule of philosophy. For if experience be any guide in philosophy, then
according to experience and observations made in respect to the only
planet that we can actually experiment on, it most conclusively follows,
that not only the earth, but every planet, and indeed every satellite
that revolves round its primary planet, is a magnet; otherwise the rule
of philosophy which permits us to formulate hypotheses based on
experience is entirely violated, and ceases at once to be an universal
rule.

So that either the earth is not a magnet, or else, being a magnet by our
second Rule of Philosophy, all the other planets are magnets also. This
conclusion has already been arrived at by Lord Kelvin, who in writing in
his