HISTORY OF PHYSICAL ASTRONOMY.
139
On the 22nd of November, 1843, M. Faye, of the Royal Observatory ofParis, discovered a comet, the motion of which could not be reconciled| with parabolic elements. Dr. Goldsmicht, a German astronomer, shortlyafterwards found that the observations might be satisfied by supposing thecomet to move in an ellipse with a period of about 7^ years. Le Yerrieri has calculated the perturbations of this comet, and has fixed the 4th of; April, 1851, as the time when it will return to its perihelion. He found! that the action of the planets would retard its arrival 7.67 days.
' We have alluded on a former occasion to the comet of 1770, generallyknown as Lexell ’s comet, which was rendered visible by the action ofJupiter in 1767, and was subsequently thrown into an orbit of largerdimensions, and rendered invisible by the action of the same planet in1779. The discovery of a new comet revolving in an elliptic orbit nearly; equal in magnitude to the orbit of Lexell ’s comet, and occupying thesame region of the heavens with it, induced some astronomers to suspect| that the two bodies were identical. M. Valz of Marseilles appears to| have first advanced this hypothesis. He remarked that, by supposing aslight increase in the period of Faye’s comet, it would have approachedvery near to Jupiter in the year 1815, and would have been so powerfullydisturbed by that planet, that if it had been previously revolving inan orbit of wider dimensions it would have been thrown by the action ofthe planet into the small ellipse in which it is now moving. Consideringnext the effect produced on Lexell’s comet by the action of Jupiter in1770, lie found by means of Burchardt’s data that the new ellipse intowhich the comet was then thrown would have a period of rather more thansixteen years. Hence, when the comet had made a little more than tworevolutions, it would have again arrived in a position favourable for theaction of Jupiter , and would be thrown into the smaller orbit in which itwas moving previous to 1770. Comparing the elements of this orbit withthose of the orbit in which Faye’s comet moved, he conceived that theresemblance was so strong as to justify the conclusion that the two orbitsreferred to the same comet, the one being periodically convertible intothe other by the disturbing action of Jupiter . This idea was no lessnovel and ingenious than it was interesting and plausible ; but, as it restedmerely on a rough estimate of Jupiter ’s influence during the period com-prised betw-een the actual appearances of the two comets, it could not be
Elements derivedby Burchardt fromthe Observationsof 1759.
Elements derivedby Lieutenant Strat-ford from the Ob-servations of 1835.
Pontdcoulant’sElements for 1835,obtained by com-puting the Pertur-bations of thePlanets.
Passage of the Perihelion, M.T. jGreenwich. J
Semi Axis Major.
Ratio of the eccentricity to the 1Semi Axis Major. J
Longitude of the Perihelion on 1the Orbit. J
Longitude of the Ascending 1Node. J
Inclination.
1759, Mar. 12.58
18.01861
0.9675571
303’ 10' V,
53’ 50' 11"
17° 37' 12"
1835, Nov. 15.93
18.0779386
0.9675509
304° 32' 9''.2
55° 8' 21".2
17° 45' 56".7
1835, Nov. 15.01
18.00008
0.9672807
304° 31' 42"
55° 10' 15"
17° 44' 53''