, a celebrated ancient astronomer, was born at Nice in Bithynia, and flourished between the 154th and 163d olympiads; or between 160 and 125 B. C. as we learn from tjie astronomical observations he tnade in that space of time. He is supposed to have been the first who, from vague and scattered observations, reduced astronomy to a science, and prosecuted the study of it systematically. Pliny, who always mentions him in terms of high commendation, says he was the lirst who attempted to take the number of the fixed stars, and his catalogue is preserved in Ptolemy’s “Almagest,” where they are all noted according to their longitudes and apparent magnitudes. Pliny places him amongst those men of a sublime genius, who, by foretelling the eclipses, taught mankind, that they ought not to be frightened at these phenomena. Thales was the first among the Greeks, uho could discover when there was to be an eclipse. Sulpitms Gailns among the Romans begun to succeed in this kind of prediction; and gave an essay of his skill very seasonably, the day before a battle was fought. "After these two, Hipparchus foretold the course of the sun and moon for 600 years calculated according to the different manner of reckoning the months, days, and hours, used by several nations, and for the different situations of places. Pliny admires him for taking an account of all the stars, and for acquainting us with their situations am! magnitudes. Hipparchus is also memorable for being the first who discovered the precession of the equinoxes.

The first observations he made were in the isle of Rhodes, which gained him the name Rhodius, and has made some moderns imagine, that there were two ancient | astronomers of that name: but afterwards he cultivated this science in Bithynia and Alexandria only. One of his works still extant, his “Commentary upon Aratus’ s Phenomena,” is properly a criticism upon Aratus, whom he charges witk having plundered Eudoxus’s books, and transcribed even those observations in which Eudoxus was mistaken. He makes the same remarks against Aratus the grammarian, who wrote “A Commentary on Aratus’s Phenomena.Peter Victorius is the first who published this “Commentary” of Hjpparchus, Florence, 1567, fol. Petavius gave afterwards a more correct edition of it: to which he added a Latin translation made by himself. Hipparchus composed several other works, of which honourable mention is made by many writers of antiquity; and upon the whole, it is universally agreed, that astronomy is greatly obliged to him for laying originally that rational and solid foundation, on which all succeeding professors of this science have built their improvements. Very ample justice is done to his merit in Bailly’s History of Astronomy. 1


Bailly, ubi supra. Martin’s Biog. Philes. Gen. Dict. —Hutton’s Dict.