and truth, thy name
shall be mentioned with honor.

NEW PERIODS IN ASTRONOMICAL SCIENCE.

It is not my intention, in dwelling with such emphasis upon the
invention of the telescope, to ascribe undue importance, in promoting
the advancement of science, to the increase of instrumental power. Too
much, indeed, cannot be said of the service rendered by its first
application in confirming and bringing into general repute the
Copernican system; but for a considerable time, little more was effected
by the wondrous instrument than the gratification of curiosity and
taste, by the inspection of the planetary phases, and the addition of
the rings and satellites of Saturn to the solar family. Newton,
prematurely despairing of any further improvement in the refracting
telescope, applied the principle of reflection; and the nicer
observations now made, no doubt, hastened the maturity of his great
discovery of the law of gravitation; but that discovery was the work of
his transcendent genius and consummate skill.

With Bradley, in 1741, a new period commenced in instrumental astronomy,
not so much of discovery as of measurement. The superior accuracy and
minuteness with which the motions and distances of the heavenly bodies
were now observed, resulted in the accumulation of a mass of new
materials, both for tabular comparison and theoretical speculation.
These materials formed the enlarged basis of astronomical science
between Newton and Sir William Herschell. His gigantic reflectors
introduced the astronomer to regions of space before unvisited--extended
beyond all previous conception the range of the observed phenomena, and
with it proportionably enlarged the range of constructive theory. The
discovery of a new primary planet and its attendant satellites was but
the first step of his progress into the labyrinth of the heavens.
Cotemporaneously with his observations, the French astronomers, and
especially La Place, with a geometrical skill scarcely, if at all,
inferior to that of its great author, resumed the whole system of
Newton, and brought every phenomenon observed since his time within his
laws. Difficulties of fact, with which he struggled in vain, gave way to
more accurate observations; and problems that defied the power of his
analysis, yielded to the modern improvements of the calculus.

HERSCHELL'S NEBULAR THEORY.

But there is no _Ultima Thule_ in the progress of science. Wi