intensity of the heat would be reduced to one-ninth; while if the
distance were four times as great, the intensity of the heat would only
be one-sixteenth of what it would receive in its first position. This
may be proved from experiments as given by Tyndall in his _Heat, a Mode
of Motion_.

Let us apply the law of inverse squares in relation to heat to the solar
system, and see what the result gives. In our solar system, we have the
sun as the central body, the source of all light and heat, with the
eight planets, Mercury, Venus, the Earth, Mars, Jupiter, Saturn, Uranus,
Neptune, describing orbits around the central body, and at the same time
receiving from it the light and heat which the sun is ever pouring
forth into space. The mean distance of Mercury from the sun is about
36,000,000 miles, while that of the Earth is about 92,000,000 miles, so
that reckoning the distance of Mercury as unity, the distance of the
Earth is a little more than 2-1/2 times that of Mercury from the sun.
Now the square of 2-1/2 is 25/4, and that inverted gives us 4/25, so
that according to the law of inverse squares, the intensity of heat at
the Earth's distance from the sun is 4/25 of what the intensity of heat
is at the mean distance of Mercury. Again, the mean distance of Mars is
141,000,000 miles, while the mean distance of Saturn is 884,000,000
miles, and taking Mars' distance from the sun as unity, the distance of
Saturn would be represented by 6-1/4. Now the square of 6-1/4 is
(25/4)^{2} which gives 625/16 and the inverse of that is 16/625, so that
the intensity of heat at the distance of Saturn's mean distance from the
sun, in comparison with the intensity of heat at Mars' mean distance,
would be about 16/625; or in other words, the heat received by Saturn
would be only 16/625 of the intensity of heat received by the planet
Mars. In Art. 63 we have seen that heat is a repulsive motion, being a
wave motion of the Aether which is propagated from the heated and
central body, which in this case is the sun. Therefore, according to the
law of inverse squares from the standpoint of heat, we find in the solar
system a repulsive motion, due to the wave motion of the Aether, which
is always exerted away from the sun in the same path that the
centripetal force takes, and which like that force diminishes in
intensity inversely as the square of the distance. So that, wherever the
centripetal force, or the attractive force of Gravitation, is dimi