4o6 THE POPULAR SCIENCE MONTHLY. 



body, which revolves around the sun in an orbit inferior to that 

 of the earth ; but little inclined to the plane of the ecliptic ; hav- 

 ing 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 con- 

 nect 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 investiga- 

 tions. His work was, furthermore, spoken of in the most compli- 

 mentary 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 con- 

 firmation of Chladni's view that the phenomenon was of cosmic- 

 al 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 communi- 

 cation to the French Academy in 1836, spoke of his " very com- 

 prehensive and highly interesting work " in collecting and mak- 

 ing 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 sug- 

 gested that the explanation of the cause of the meteors of Novem- 

 ber 13th might include that of the zodiacal light. He further 

 published a well-matured thory of the nebulous body represent- 

 ed 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 con- 

 tributed 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 



