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Contents
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. |
102–25 |
CHAPTER X.
REMARKABLE COMETS.
Suggested list of those which deserve the name.—The Great Comet of 1811.—The Great Comet of 1843.—The Great Comet of 1858.—Evidence to enable these three Comets to be compared.—The Great Comet of 1861.—The Comet of 1862 (iii.).—The Comet of 1874 (iii.).—The Comet of 1880 (i.).—The Great Comet of 1882 (iii.).—Peculiarities of its orbit.—The Comet of 1887 (i.).—Sawerthal's Comet of 1888 (i.).—The Comet of 1901 (i.) |
126–59 |
CHAPTER XI.
THE ORBITS OF COMETS.
All Cometary Orbits sections of a Cone.—The different kinds of Sections.—The Circle.—The Ellipse.—The Hyperbola.—The Parabola.—The last-named the most easy to calculate.—An ellipse very troublesome to calculate.—The elements of a Comet's Orbit.—For a Parabolic Orbit 5 in number.—Statement of various details connected with Orbits.—Direction of motion.—Eccentricity of an Elliptic Orbit.—The various elements represented by certain symbols.—Number of comets whose orbits have been calculated.—The significance of the different orbits pursued by comets. |
160–73 |
