Page:The story of the comets.djvu/252

of 1862 (iii.). The resemblance will be best seen by putting the two sets of figures side by side thus:—

	August Meteors.	Comet of 1862 (iii.).
Perihelion passage	1862, July 13	1862, Aug. 22. 9
Longitude of perihelion	343º 28′	344º 41′
Ascending node	138º 16′	137º 27′
Inclination of orbit	64º 3′	66º 25′
Perihelion distance	0.9643	0.9626
Period	105 years?	123.4 years
Direction of motion	Retrograde	Retrograde

Whilst it must be admitted that the estimate of the periods is uncertain the general resemblance of the other elements of the two orbits is too unmistakable to permit of any doubt being thrown on the fact that meteors and comet were moving in orbits identical in form. The return of this meteor-comet is to be looked for in 1985.

Now we must go back to a consideration of Adams's results, and they follow the precedent established by Schiaparelli; for the elements of the November meteors (treating their orbit as an ellipse) were found reproduced almost precisely in the elements of the Comet of 1866 (i.) as found by Oppolzer. Adams presented them in the following form:—

Period	33.25 years (assumed)	33.18
Mean distance	10.3402	10.3248
Eccentricity	0.9047	0.9054
Perihelion distance	0.9855	0.9765
Inclination	16º 46′	17º 18′
Longitude of node	51º 28′	51º 26′
Distance of perihelion from node	6º 5′	9º 2′
Direction of motion	Retrograde	Retrograde

A separate group of the Leonids is also suspected to exist, preceding the principal one by about 12 years (or about 1/3^rd of a revolution) in its appearance. Notable meteor showers are recorded to have taken place in 855–56, 1787, 1818–23, and 1852, agreeing exactly with the principal cluster in the day and very closely also in the period of their returns.^[1] The original dismemberment of the comet (assuming that a comet was in question) to which the ancient record of this widely

1. Nature, vol. xi, p. 407, March 25, 1875; vol. xii, p. 85, June 3, 1875.