r iodine."

Here, then, from the pen of one of the greatest thinkers and
experimentalists of modern times we have confirmatory evidence that the
mass of any body is practically synonymous with the quantity of
electricity associated with that body. For if the principle is true in
its application to atoms, it is true in its application to molecules;
and if it is true in relation to molecules, it is equally true in
relation to small bodies composed of molecules. And if it holds good in
relation to small bodies, the principle is equally true in its
application to larger bodies, as the earth, and therefore is of
universal application and proves the statement already made, that the
masses of bodies and quantities of electricity in association with that
mass are always proportionate to each other.

We are now in a position to compare the proportion of the centripetal
and centrifugal forces. The attractive power of the former, between two
bodies, is equal to the product of their masses; the repulsive power of
the latter is equal to the product of the quantities of electricity
bound to them, and that, as we have seen, is regulated by the respective
mass of each body. Let us apply this fact to the solar system and see
how it works.

Taking the mass of the earth as unity, we find that the mass of the sun
is 324,000 greater, so that the attractive power of the two bodies would
be represented by the product of the two numbers; but because the sun is
that number of times greater, its aetherial and, therefore, its electric
field would be so many times greater, with the result that the
proportion of the repulsive forces between the two bodies would be
exactly the same as the attractive forces between the two bodies, that
is, if the mean distance remains the same.

In the same way, it can be shown that the attractive forces between the
earth and Jupiter exactly equal the repulsive forces between the two
planets at their mean distance, or the attractive forces between any two
planets or satellites are exactly counterbalanced by the repulsive power
of the centrifugal force at their mean distances.

Thus the centrifugal force of every body is the exact opposite of its
centripetal force at their mean distance, because the laws governing the
centrifugal force are the exact counterpart of the laws governing the
centripetal force. A comparison of the two will prove this. From Arts.
20, 21, and 22 we have seen that the centripetal force is