f order, harmony,
and design.

CHAPTER II

ASTRONOMY IN THE SEVENTEENTH CENTURY

The seventeenth century embraces the most remarkable epoch in the whole
history of astronomy. It was during this period that those wonderful
discoveries were made which have been the means of raising astronomy to
the lofty position which it now occupies among the sciences. The
unrivalled genius and patient labours of the illustrious men whose names
stand out in such prominence on the written pages of the history of this
era have rendered it one of the most interesting and elevating of
studies. Though Copernicus lived in the preceding century, yet the names
of Tycho Brahe, Kepler, Galileo, and Newton, testify to the greatness of
the discoveries that were made during this period, which have surrounded
the memories of those men with a lustre of undying fame.

Foremost among astronomers of less conspicuous eminence who made
important discoveries in this century we find the name of Huygens.

CHRISTIAN HUYGENS was born at The Hague in 1629. He was the second son
of Constantine Huygens, an eminent diplomatist, and secretary to the
Prince of Orange. Huygens studied at Leyden and Breda, and became
highly distinguished as a geometrician and scientist. He made important
investigations relative to the figure of the Earth, and wrote a learned
treatise on the cause of gravity; he also determined with greater
accuracy investigations made by Galileo regarding the accelerated motion
of bodies when subjected to the influence of that force.

Huygens admitted that the planets and their satellites attracted each
other with a force varying according to the inverse ratio of the squares
of their distances, but rejected the mutual attraction of the molecules
of matter, believing that they possessed gravity towards a central point
only, to which they were attracted. This supposition was at variance
with the Newtonian theory, which, however, was universally regarded as
the correct one.

Huygens originated the theory by which it is believed that light is
produced by the undulatory vibration of the ether; he also discovered
polarization.

Up to this time the method adopted in the construction of clocks was not
capable of producing a mechanism which measured time with sufficient
accuracy to satisfy the requirements of astronomers. Huygens endeavoured
to supply this want, and applied his mechanical ingenuity in
constructing a clock that could be relied