CHAPTER IX.
HALLEY'S COMET.
Halley's Comet by far the most interesting of the Periodic Comets.—Sir I. Newton and the Comet of 1680.—This Comet the first to which the theory of Gravitation was applied.—The Comet of 1682.—Description of it by various observers.—Luminous Sector seen by Hevelius.—Halley's application to it, and the Comets of 1531 and 1607, of Newton's mathematical researches.—He finds the elements of the three very similar, and suspects the three comets are really one.—With a probable period of 75 years.—Suspects the disturbing influence of planets on Comets.—Of Jupiter's influence especially.—Halley's final conclusion that the Comet would reappear in 1758.—Preparations by Clairaut and Lalande to receive it.—The Comet found by an amateur named Palitzsch near Dresden.—Some account of this man.—The Comet generally observed in Europe.—Trick played by Delisle on Messier.—Return of the Comet in 1835.—Great preparations by Mathematicians to receive it.—These specially took into account planetary perturbations.—Predicted date of perihelion passage.—The Comet discovered by telescopes as expected.—Some particulars of the observations.—The past history of Halley's Comet traced back through many centuries.—Researches of Hind.—Confirmed in the main by Crommelin and Cowell.—Some quotations from old Chroniclers.—Observations by the Chinese of great value.—Halley's Comet in 1066.—Figured in the Bayeux Tapestry.—The Comet's various returns ascertained with certainty backwards to B.C. 250.
The comet known as Halley's may be regarded as by far the most interesting of all the comets recorded in history; and this, whether looked at from the standpoint of the historian or of the astronomer; and having regard to the position which it has occupied during many centuries in the public mind, and is likely also to occupy during the year 1910, it will be worth while to review its career in some detail.
A few years after the advent of the celebrated Comet of 1680 Sir I. Newton published his epoch-making Principia, in which he first promulgated the Theory of Gravitation, and applied it to the orbit of that comet. He explained the
