result, several outstanding
problems will be explained on a physical basis, which at the present
time cannot be satisfactorily explained except from the mathematical
standpoint.

ART. 6. _3rd Rule. Satisfactory explanation of the Phenomena sought to
be Explained._--The third rule which governs the making of any
hypothesis is, that the hypothesis formed in accordance with the first
and second rules shall satisfactorily account for all the phenomena
sought to be explained.

Newton writes on this point as follows: "No more causes of natural
things are to be admitted, than such as are true, and sufficient to
explain the phenomena." While again in his fourth rule he states: "In
experimental philosophy, propositions collected by induction from
phenomena are to be regarded as accurately true, or very nearly true,
notwithstanding any contrary hypothesis, till other phenomena occur by
which they are made more accurate, or are rendered subject to
exceptions." _Principia_, Book 3. Herschel in his _Natural Philosophy_
points out, that one of the chief requirements of any assumed hypothesis
is, that it shall be sufficient to account for the phenomena to be
explained, and that it shall be suggested by analogy.

Now the object of this work is to give a physical explanation of the
cause and working of Gravitation, and to show how, by the properties,
qualities and motions of the universal Aether, Universal Gravitation may
be accounted for on a physical basis. So that every phenomenon,
associated with, or included in the Law of Gravitation, should receive a
satisfactory physical explanation by the proposed theory.

Thus the physical cause of the centripetal and centrifugal forces should
receive for the first time a physical explanation.

Newton's Laws of Motion, in so far as they conform to his own Rules of
Philosophy, should also receive a physical explanation.

Kepler's Laws, which govern the motion of planets in their orbits,
should also receive a similar physical explanation. Indeed, all
phenomena which the Law of Gravitation explains from a mathematical
standpoint, ought to receive a physical explanation by the proposed new
conception of the Aether medium.

In addition to the outstanding physical cause of Gravitation, there are
other physical problems that yet remain to be solved; as, for example,
there is the question as to what is the relative motion of Aether to
moving matter. Does the Aether move with matter through sp