t in
which Galileo died. At the age of fifteen he was employed on his mother's
farm, but had already displayed such an ardor for learning that he was
sent first to school and then to Cambridge, where he was soon conspicuous
for his talents and his genius. In due time he was made a professor. His
discoveries in astronomy, mechanics, and optics are of world-wide renown.
The law of gravitation was established by him, and set forth in his paper
_De Motu Corporum_. His treatise on _Fluxions_ prepared the way for that
wonderful mathematical, labor-saving instrument--the differential
calculus. In 1687 he published his _Philosophiae Naturalis Principia
Mathematica_, in which all his mathematical theories are propounded. In
1696 he was made Warden of the Mint, and in 1699 Master of the Mint. Long
a member of the Royal Society, he was its president for the last
twenty-four years of his life. In 1688 he was elected member of parliament
for the university of Cambridge. Of purely literary works he left two,
entitled respectively, _Observations upon the Prophecies of Daniel and the
Apocalypse of St. John_, and a _Chronology of Ancient Kingdoms Amended_;
both of which are of little present value except as the curious remains of
so great a man.

_Viscount Bolingbroke_ (Henry St. John), 1678-1751: as an erratic
statesman, a notorious free-thinker, a dissipated lord, a clever political
writer, and an eloquent speaker, Lord Bolingbroke was a centre of
attraction in his day, and demands observation in literary history. During
the reign of Queen Anne he was a plotter in favor of the pretender, and
when she died, he fled the realm to avoid impeachment for treason. In
France he joined the pretender as Secretary of State, but was dismissed
for intrigue; and on being pardoned by the English king, he returned to
England. His writings are brilliant but specious. His influence was felt
in the literary society he drew around him,--Swift, Pope, and
others,--and, as has been already said, his opinions are to be found in
that _Essay on Man_ which Pope dedicated to him. In his meteoric political
career he represents and typifies one phase of the time in which he lived.

_George Berkeley_, 1684-1753: he was educated at Trinity College, Dublin,
and soon engaged in metaphysical controversy. In 1724 he was made Dean of
Derry, and in 1734, Bishop of Cloyne. A man of great philanthropy, he set
forth a scheme for the founding of the _Bermudas College_, to