any intervening substance; and is transmitted
instantaneously, whatever the distance may be.

While, therefore, it is impossible to divest matter
of this property, there are two conditions
which neutralize its effect. The first of these is
position. Let us take two balls, one solid and
the other hollow, but of the same mass, or density.
If the cavity of the one is large enough to receive
the other, it is obvious that while gravity is still
present the lines of attraction being equal at
all points, and radially, there can be no pull which
moves them together.

DISTANCE REDUCES GRAVITATIONAL PULL.--Or
the balls may be such distance apart that the attractive
force ceases. At the center of the earth
an object would not weigh anything. A pound
of iron and an ounce of wood, one sixteen times
the mass of the other, would be the same,--absolutely
without weight.

If the object should be far away in space it
would not be influenced by the earth's gravity;
so it will be understood that position plays an
important part in the attraction of mass for mass.

HOW MOTION ANTAGONIZES GRAVITY.--The second
way to neutralize gravity, is by motion. A
ball thrown upwardly, antagonizes the force of