nfluence of the sun; the correspondence between
the calculated and observed quantities of these inequalities; the
extension of the doctrine to satellites of other planets, as those of
Jupiter; the determination of the earth's figure; the causes of the
tides; the different force of gravity in different latitudes, and a
multitude of other phenomena. The theory asserted for itself that
authority which belongs to intrinsic truth. It enabled mathematicians to
point out facts not yet observed, and to foretell future events.

And yet how hard it is for truth to force its way when bigotry resists.
In 1771, the University of Salamanca, being urged to teach physical
science, refused, and this was its answer; "Newton teaches nothing that
would make a good logician or metaphysician; and Gassendi and Descartes
do not agree so well with revealed truth as Aristotle does."

[Sidenote: The earth in time.] Among the interesting results of Newton's
theory may be mentioned its application to secular inequalities, such as
the acceleration of the moon's mean motion, that satellite moving
somewhat quicker now than she did ages ago. Laplace detected the cause
of this phenomenon in the influence of the sun upon the moon, combined
with the secular variation of the eccentricity of the earth's orbit.
Moreover, he showed that this secular inequality of the motion of the
moon is periodical, that it requires millions of years to re-establish
itself, and that, after an almost inconceivable time, the acceleration
becomes a retardation. In like manner, the same mathematician explained
the observed acceleration in the mean motion of Jupiter, and retardation
of that of Saturn, as arising from the mutual attraction of the two
planets, and showed that this secular inequality has a period of 929-1/2
years. With such slow movements may be mentioned the diminution of the
obliquity of the ecliptic, which has been proceeding for ages, but which
will reach a limit and then commence to increase. These secular motions
ought not to be without interest to those who suffer themselves to adopt
the patristic chronology of the world, who suppose that the earth is
only six thousand years old, and that it will come to an end in about
one thousand years more. They must accept, along with that preposterous
delusion, its necessary consequences, that the universe has been so
badly constructed, and is such a rickety machine, that it can not hold
together long enough for some of