nconsiderately entrusted to
foreigners, to the prejudice of Frenchmen abounding in intelligence and
zeal. Subsequently, intellects of a superior order struggled with
courage, but in vain, against the unskilfulness of our artists. During
this period, Bradley, more fortunate on the other side of the Channel,
immortalized himself by the discovery of aberration and nutation.

The contribution of France to these admirable revolutions in
astronomical science, consisted, in 1740, of the experimental
determination of the spheroidal figure of the earth, and of the
discovery of the variation of gravity upon the surface of our planet.
These were two great results; our country, however, had a right to
demand more: when France is not in the first rank she has lost her
place.[24]

This rank, which was lost for a moment, was brilliantly regained, an
achievement for which we are indebted to four geometers.

When Newton, giving to his discoveries a generality which the laws of
Kepler did not imply, imagined that the different planets were not only
attracted by the sun, but that they also attract each other, he
introduced into the heavens a cause of universal disturbance.
Astronomers could then see at the first glance that in no part of the
universe whether near or distant would the Keplerian laws suffice for
the exact representation of the phenomena; that the simple, regular
movements with which the imaginations of the ancients were pleased to
endue the heavenly bodies would experience numerous, considerable,
perpetually changing perturbations.

To discover several of these perturbations, to assign their nature, and
in a few rare cases their numerical values, such was the object which
Newton proposed to himself in writing the _Principia Mathematica
Philosophiae Naturalis_.

Notwithstanding the incomparable sagacity of its author the Principia
contained merely a rough outline of the planetary perturbations. If this
sublime sketch did not become a complete portrait we must not attribute
the circumstance to any want of ardour or perseverance; the efforts of
the great philosopher were always superhuman, the questions which he did
not solve were incapable of solution in his time. When the
mathematicians of the continent entered upon the same career, when they
wished to establish the Newtonian system upon an incontrovertible basis,
and to improve the tables of astronomy, they actually found in their way
difficulties which the genius of