We may now turn to more recent times, and it will be convenient to
divide our subjects according to the branch of science in which they
were distinguished, and to commence with

MATHEMATICIANS,

of whom Ireland may boast of a most distinguished galaxy.

Sir William Rowan Hamilton (b. in Dublin 1805, d. 1865), belonged to
a family, long settled in Ireland, but of Scottish extraction. He was
a most precocious child. He read Hebrew at the age of seven, and at
twelve, had studied Latin, Greek, and four leading continental
languages, as well as Persian, Syriac, Arabic, Sanscrit, and other
tongues. In 1819 he wrote a letter to the Persian ambassador in that
magnate's own language. After these linguistic contests, he early
turned to mathematics, in which he was apparently self-taught; yet,
in his seventeenth year he discovered an error in Laplace's
_Mécanique Céleste_. He entered Trinity College where he won all
kinds of distinctions, being famous not merely as a mathematician,
but as a poet, a scholar, and a metaphysician. He was appointed
Professor of Astronomy and Astronomer Royal whilst still an
undergraduate. He predicted "conical refraction," afterwards
experimentally proved by another Irishman, Humphrey Lloyd. He twice
received the Gold Medal of the Royal Society: (i) for optical
discoveries; (ii) for his theory of a general method of dynamics,
which resolves an extremely, abstruse problem relative to a system of
bodies in motion. He was the discoverer of a new calculus, that of
Quaternions, which attracted the attention of Professor Tait of
Edinburgh, and was by him made comprehensible to lesser