ipetal Force_. Further, as the Centripetal
Force is an attractive Force ever attracting to a centre, so the
Centrifugal Force, being its exact opposite, is a repulsive Force, which
fulfils all the laws and conditions which govern the Centripetal Force,
as it is in every phase and aspect the exact opposite, being indeed its
complement and counterpart.

Any physical explanation of the Law of Gravitation, therefore, must also
give a satisfactory physical explanation of this Force, and show its
mode of operation and working. This I premise I will do without the
faintest shadow of doubt or failure; that is, if we are to accept the
evidence of some of the most delicate experiments of modern times
relative to aetherial physics.

ART. 12. _Laws of Motion._--One of the most important factors in the
successful application of the Attraction of Gravitation to the universe
at large, are the Laws of Motion enunciated by Sir Isaac Newton. These
are three in number, and are as follows--

1st. Every body continues in its state of rest, or of uniform motion in
a straight line, except in so far as it may be compelled by impressed
Forces to change that state.

2nd. Change of motion is proportionate to the impressed Force, and takes
place in the direction of the straight line in which the Force acts.

3rd. To every action there is always an equal and contrary reaction.

_Corollary._--To these must be added the first Corollary of the three
laws which is commonly known as the Parallelogram of Forces, which is as
follows: "That when a body is acted upon by two Forces at the same time,
it will describe a diagonal, by the motion resulting from their
composition, in the same time that it would describe the sides of the
parallelogram."

Now let us apply Newton's Rules of Philosophy to these laws, and see if
they fulfil the conditions laid down therein.

In the first place, there being three laws necessary to cover all the
motions involved, there is not that simplicity of conception which is a
primary factor in the making of any hypothesis. Then it will be observed
that even after postulating the three laws, Newton was unable to account
for the elliptic orbits of the planets, until he had added a Corollary
known as the Parallelogram of Forces.

ART. 13. _Force._--The question has arisen also, as to the meaning of
the term Force which Newton uses. What is a Force, its cause and mode of
operation? The idea of Force is conveyed to us by