ce; it hangs in empty space.
It has no tendency to rise; none to fall; none to move at all in
any direction. It seethes and, flames, and holds itself together
by attractive power, and that is all the force with which we have
endowed it.

Leave it there alone, and withdraw millions of miles into space:
it looks smaller and smaller. We lose sight of those distinctive
spires of flame, those terrible movements. It only gives an even
effulgence, a steady unflickering light. Turn one quarter round.
Still we see our world, but it is at one side.

Now in front, in the utter darkness, suddenly create another world
of the same size, and at the same distance from you. There they
stand--two huge, lone bodies, in empty space. But we created them
dowered with attraction. Each instantly feels the drawing influence
of the other. They are mutually attractive, and begin to [Page 8]
move toward each other. They hasten along an undeviating straight
line. Their speed quickens at every mile. The attraction increases
every moment. They fly swift as thought. They dash their flaming,
seething foreheads together.

And now we have one world again. It is twice as large as before,
that is all the difference. There is no variety, neither any motion;
just simple flame, and nothing to be warmed thereby. Are our creative
powers exhausted by this effort?

[Illustration: Fig. 1.--Orbit A D, resulting from attraction, A
C, and projectile force, A B.]

No, we will create another world, and add another power to it that
shall keep them apart. That power shall be what is called the force
of inertia, which is literally no power at all; it is an inability
to originate or change motion. If a body is at rest, inertia is
that quality by which it will forever remain so, unless acted upon
by some force from without; and if a body is in motion, it will
continue on at the same speed, in a straight line, forever, unless
it is quickened, retarded, or turned from its path by some other
force. Suppose our newly created sun is 860,000 miles in diameter.
Go away 92,500,000 miles and create an earth eight thousand miles
in diameter. It instantly feels the attractive power of the sun
drawing it to itself sixty-eight [Page 9] miles a second. Now, just
as it starts, give this earth a push in a line at right angles with
line of fall to the sun, that shall send it one hundred and
eighty-nine miles a second. It obeys both forces. The result is that
the world moves constant