Discussion of the Phenomena.
Since the memorable display of November 13th, 1833, the phenomena of shooting-stars have been observed and discussed by Brandes, Benzenberg, Olbers, Saigey, Heis, Olmsted, Herrick, Twining, Newton, Greg, and many others. In the elaborate paper of Professor Olmsted, it was shown that the meteors had their origin at a distance of more than 2000 miles from the earth's surface; that their paths diverged from a common point near the star Gamma Leonis; that in a number of instances they became visible about 80 miles from the earth's surface; that their velocity was comparable to that of the earth in its orbit; and that in some cases their extinction occurred at an elevation of 30 miles. It was inferred, moreover, that they consisted of combustible matter which took fire and was consumed in passing through the atmosphere; that this matter was derived from a nebulous body revolving round the sun in an elliptical orbit, but little inclined to the plane of the ecliptic; that its aphelion was near that point of the earth's orbit through which we annually pass about the 13th of November—the perihelion being a little within the orbit of Mercury; and finally that its period was about one-half that of the earth. Dr. Olmsted subsequently modified his theory, having been led by further observations to regard the zodiacal light as the nebulous body from which the shooting-stars are derived. The latter hypothesis was also adopted by the celebrated Biot.
The fact that the position of the radiant point does not change with the earth's rotation, places the cosmical origin of the meteors wholly beyond question. The theory of a closed ring of nebulous matter revolving round the sun in an elliptical orbit which intersects that of the earth, affords a simple and satisfactory explanation of the phenomena. This theory was adopted by Humboldt, Arago, and others, shortly after the occurrence of the meteoric shower of 1833. That the body which furnishes the material of these meteors moves in a closed or elliptical orbit is evident from the periodicity of the shower. It is also manifest from the partial recurrence of the phenomenon from year to year, that the matter is diffused around the orbit; while the extraordinary falls of 1833, 1799, 1366, and 1202, prove the diffusion to be far from uniform.