3. Q. What is inertia? A. 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.
4. Q. What is the result of the action of attraction and inertia upon
two revolving bodies? A. They circle about each other as long as these
forces endure.
5. Q. What would be the solution of the problem of a simple revolution
of one world about another in a circular orbit? A. It would always be
at the same distance from its center, and going with the same velocity.
6. Q. In the case of the moon, how many causes are there that interfere
with such a simple orbit? A. Over sixty.