The Hon. Robert Boyle was born at Lismore, in the county Waterford, in 1627, being the fourteenth child of the first Earl of Cork. On his tombstone he is described as "The Father of Chemistry and the Uncle of the Earl of Cork", and, indeed, in his _Skyptical Chimist_ (1661), he assailed, and for the time overthrew, the idea of the alchemists that there was a _materia prima_, asserting as he did that theory of chemical "elements" which held good until the discoveries in connection with radium led to a modification in chemical teaching. This may be said of Boyle, that his writings profoundly modified scientific opinion, and his name will always stand in the forefront amongst those of chemists. He made important improvements in the air-pump, was one of the earliest Fellows of the Royal Society, and founded the "Boyle Lectures." He died in 1691. Sir Thomas Molyneux was born in Dublin, in 1661, of a family which had settled in Ireland about 1560-70. He practised as a physician in his native city, was the first person to describe the Irish Elk and to demonstrate the fact that the Giant's Causeway was a natural and not, as had been previously supposed, an artificial production. He was the author of many other scientific observations. He died in 1733. 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 mathematicians. It is far too abstruse for description here.