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 having hown, by his ublime Theory, the Coure and Inequalities of the Planets, he ubjects Comets to the ame Law. The Orbit of thee Fires (unknown for o great a Series of Years,) which was the Terror of Mankind, and the Rock againt which Philoophy plit; plac'd by Aritotle below the Moon, and ent back by Des Cartes above the Sphere of Saturn, is at lat plac'd in its proper Seat by Sir Iaac Newton.

proves that Comets are olid Bodies which move in the Sphere of the Sun's Activity; and that they decribe an Ellipis o very eccentric, and o near to Parabola's, that certain Comets mut take up above five hundred Years in their Revolution.

learned Dr. Halley is of opinion, that the Comet een in 1680, is the ame which appear'd in Julius Cæar's Time. This hows more than any other, that Comets are hard, opake Bodies; for it decended o near to the Sun, as to come within a ixth Part of the Diameter of this Planet from It; and cone-