body, which revolves around the sun in an orbit inferior to that of the earth; but little inclined to the plane of the ecliptic; having its aphelion near to the earth's path; and having a periodic time of one hundred and eighty-two days, nearly," Two of the principal features of this theory those of the cosmical origin of the meteors and their periodicity—are still maintained; but instead of one periodical shower, astronomers now count several; and instead of a single infraterrestrial nebulous body, they connect the several showers each with a particular comet. Priority in putting forth these conceptions was disputed by Chladni, whose claims, however, do not seem to have been so definitely established as those of Prof. Olmsted. Of course, the suggestion of the cosmical origin of meteors, as a suggestion, was never wholly new, for it had been made in general terms by other philosophers, from Anaxagoras down; but the credit is claimed for Prof. Olmsted of having first embodied it in a definite, coherent theory, accompanied with valid evidence; whether or how far Chladni may have anticipated him, his conclusions, as Prof. Silliman well says, were undoubtedly original with himself, and entirely independent of any results of preceding investigations. His work was, furthermore, spoken of in the most complimentary terms by the most distinguished foreign students in those lines of the day. Humboldt referred, in the first volume of his Cosmos, to the excellent description which Prof. Olmsted had given of the shower in November, 1833, and to his brilliant confirmation of Chladni's view that the phenomenon was of cosmical origin. Olbers praised him for his circumstantial description and collection of particulars of the shower, and agreed with him in the conclusion that it came from abroad. Biot, in a communication to the French Academy in 1836, spoke of his "very comprehensive and highly interesting work" in collecting and making known "all the circumstances of position, direction, and periodicity peculiar to the meteors of the 13th of November."
In his first memoir on the shooting stars. Prof. Olmsted suggested that the explanation of the cause of the meteors of November 13th might include that of the zodiacal light. He further published a well-matured thory of the nebulous body represented by the zodiacal light. Biot agreed with him in this view, and recognized his priority in the conception. Astronomy has not yet satisfied itself concerning the nature of this phenomenon. He also studied the aurora borealis, concerning which he contributed articles to the American Journal of Science in 1835 and 1837, and gave at length a theory of cosmical origin and secular period in the eighth volume of the Smithsonian Contributions to Knowledge.
He thus ascribed shooting stars, auroras, and the zodiacal
