166 TENTH ANNUAL REPORT OF 



to his deatli ; it was also advocated, on chemical grounds, by Berze- 

 lius, whom I have no reason to believe ever changed his views in re- 

 gard to it ; and to these we have to add the following distinguished 

 mathematicians and philosophers : Biot, Brandes, Poisson, Quetelet, 

 Arago, and Benzenberg, who have at one time or another advocated 

 the lunar origin of meteorites. 



Some of the above astronomers abandoned the theory — among them 

 Olbers and Arago; but they did not do so from any supposed defect in 

 it, but from adopting the assumption that shooting stars and mete- 

 orites were the same, and on studying the former and applying the 

 phenomena attendant upon them to meteorites^ the supposed lunar 

 origin was no longer possible. 



On referring to the able researches of Sears C. Walker on the_ peri- 

 odical meteors of August and November, (Am. Phil. Soc.^,) it will be 

 found that astronomer makes the following remarks: "In 1836, Ol- 

 bers, the original proposer of the theory of 1795, being firmly con- 

 vinced of the correctness of Brandes's estimate of the relative velocity 

 of meteors, renounces his selenic theory, and adopts the cosmical theo- 

 ry as the only one which is adeq^uate to explain the established facts 

 before the public." 



For reasons already stated, it appears wrong to assume the identity 

 of meteorites and shooting stars ; so that whatever difficulty the phe- 

 nomena of the latter may have interposed as to the hypothesis of the 

 origin of meteoric stones, it now no longer exists. Had Olbers 

 viewed the matter in this light, he would doubtless _ have retained 

 his original convictionS;, to which no material objection appears to 

 have occurred to him for forty years. 



It is not my object to enter upon all the points of plausibility of 

 this assumed origin, or to meet all the objections which have been 

 urged against it. The object now is simply to urge such facts as 

 have been developed ia this lecture, and which appear to give strength 

 to the hypothesis. They may be summed up under the following 

 heads : 



1. That all meteoric masses have a community of origin. 



2. At one period they formed parts of some large body. 



3. They have all been subject to a more or less prolonged igneous 

 action corresponding to that of terrestrial volcanoes. 



4. That their source must be deficient in oxygen. 



5. That their average specific gravity is about that of the moon. 

 From what has been said under the head of common characters of 



meteorites, it would appear far more singular that these bodies should 

 have been formed separately, than that they should have at some time 

 constituted parts of the same body ; and from the character of their 

 formation, that body should have been of great dimensions. Let us 

 suppose all the known meteorites assembled in one mass, and regarded 

 by the philosopher, mindful of our knowledge of chemical and physi- 

 cal laws. Would it be considered more rational to view them as the 

 great representatives of some one body that had been broken into 

 fragments, or as small specks of some vast body in space that at one 

 period or another has cast them forth ? The latter it seems to me is 



