METEORS OF AUGUST AND NOVEMBER. 119 



Waive his theory of the cosmical origin of meteors, and to resort again to that 

 of a terrestrial origin. It does not appear that much new light was thrown 

 upon this subject previous to the resumption of corresponding observations by 

 Brandes and others in 1823, and Quetelet and others in 1824. The three the- 

 orieS) cosmical, selenitic, and terrestrial, had each their advocates. The first 

 failed to account for the upward motion of meteors, if not for the uniformity 

 of chemical constituents. The second accounted for the chemical facts, but 

 failed to explain the upward motion of a meteor, as well as their great relative 

 velocity, computed by Brandes in 1798. The last accounted for the upward 

 motion, but not for the relative velocity nor chemical constituents. The chemi- 

 cal objection could be partly removed by a resort to the earth's atmosphere for 

 the origin of motion; which would also account, though rather unsatisfactorily, 

 for their upward motion, but would still be inadequate to explain their observed 

 relative velocity.''^ 



As late as 1834, Berzelius,^' and also Benzenberg, express themselves de- 

 cidedly in favour of the Olbersian or selenitic theory. In 1836, however. Gi- 

 bers, the original proposer of the theory in 1795, being firmly convinced of the 

 correctness of Brandes' estimate of the relative velocity of meteors, renounces 

 his selenitic theory, and adopts the cosmical theory as the only one which is 

 adequate to explain the established facts then before the public. Arago and 

 Quetelet had previously done the same. Littrow, in 1838, and Bessel, in 

 1839, fall in with the others. Professor Erman, Jun., in Berlin, and Bogus- 

 lawski,^^ in Breslaw, in ]839 and 1840, have extended their inquiries on the 

 bearing of the facts known up to these dates upon the cosmical theory. It is 

 to Bessel's paper, already quoted, that we are indebted for the removal of the 

 principal ground of objection to the cosmical theory, namely, that of the ascent 

 of meteors. He has there shown that every instance in which Brandes' com- 

 putations gave an upward motion of a meteor may be made to indicate the re- 

 verse, by applying a correction of the observed points of beginning and end of 

 the apparent path of a meteor not much exceeding the probable error of such 



7* Dr. Olbers accounts for the serpentine motion of meteors that approach near the earth's sur- 

 face, by partial explosions, after the manner of rockets. 

 75 Olbers' paper, Schumacher's Jahrbuch for 1837, p. 54. 

 78 Astr. Nachr., 391 and 412. 



