GREGORY, Olinthus, LL.D., was born in 1774 at Yaxley in Huntingdonshire. He first acquired distinction through his Treatise on Astronomy, and by his Pantologia, a sort of cyclopaedia of the arts and sciences which he edited. In 1802 he was appointed mathematical master, and, some years later, professor, in the Military School at Woolwich, where he remained till 1838, when bad health compelled him to retire. During this long period of time he published a number of works, some of them of considerable value, such as his Elements of Plane and Spherical Trigonometry; Mathematics for Practical Men; Letters on the Evidences of Christianity, &c. His work on Mechanics is a good popular treatise on the subject, and one that has proved very valuable to many artisans whom want of mathematical knowledge has debarred from the perusal of more scientific works. Dr Gregory died in 1841.