Atmospheric Origin of the Aurora^ ^"c. 145 



Art. XIII. — On the Atmospheric Origin of the Aurora mid its 

 Connexion with the Crystallization of Snoio ; by B. F. Joslin, 

 M. D., of the city of New York, and late Professor of Natural 

 Philosophyj &c. in Union College, Schenectady. 



New York, 122 Bleecker street, Aug. 17th, 1838. 



TO PROF. SILLIMAN. 



Dear Sir, — There appears to be increasing evidence of an in- 

 timate connexion between the aurora and atmospheric va])or, a 

 connexion which has not been wholly overlooked by recent ob- 

 servers. Recent epochs may have been more favorable to its ex- 

 hibition in the middle latitudes. In the two brief notices of the 

 aurora in the Transactions of the British Association, which met 

 in August, 1837, this is the most prominent feature. In one, 

 Dr. Traill describes the contemporaneous exhibition of station- 

 ary cirri aiid auroral streamtirs, and, in' the other, Mr. Herapath 

 attempts to refer the aurora to the precipitation of aqueous vapor. 

 Still earlier, in your own respectable Journal, in a notice of my 

 theory, published in 1836, there was an implied acknowledgment 

 of the existence of some kind of auroral vapor, and even of its 

 magnetic properties. 



In March, 1836, there were published Observations on fifty six 

 Auroras, seen by me at Schenectady, N. Y., within the five pre- 

 ceding years, and some new views as to the connexion between 

 this meteor and clouds, rain and snow.* 



The author desires to avail himself of the wider circulation of 

 the Journal of Science to communicate to the public some of the 

 principal results, to add others in confirmation of the same views, 

 and to correct a misapprehension which may prevail in relation to 

 the elevation which he assigns to this meleor.f The small ele- 

 vation which he is supposed to have assigned it is the only objec- 

 tion which he has seen made to his views. 



* Vide Appendix No. 2, to the Report of the Regents of the University of the 

 State of New York, and the same in a pamphlet of sixty nine pages, entitled 

 "Meteorological Observations and Essays." 



. For the sake of convenience, the terra meteor will he used in its more com- 

 prehensive sense. 



Vol. XXXY.— No. 1. 19 



