INTRODUCTORY LETTER 



Professor Joseph Henry, 



Secretary Smithsonian Institution. 



Sir : In compliance with your request, I place in your hands the collection of 

 observations on the Aurora Borealis, which was made in great part while I was 

 engaged, during the evening hours of relaxation, for several years prior to 1851, 

 in the examination of another, and, to me, at the time, a more interesting subject. 

 In the course of this investigation I met with so many notices of the Aurora, that 

 I thought it worth the time it would take, to gather such of them as came within 

 my reach without leaving the path over which I was travelling; it also occurred 

 to me that such a collection, covering so broad a surface, might be useful in any 

 investigation of the phenomenon, in so far at least, as it would furnish the means 

 of a ready reference to many of the observations recorded by careful and compe- 

 tent observers. 



The accompanying papers are my original notes, as they were made from time 

 to time, from the later voyages, travels, and explorations in the northern regions, 

 and particularly in the northern portions of North America. A list of the journals, 

 &c, that I have gone over, which is added, will show how far my examination 

 has extended. 



You will perceive that very few of the Auroral observations I have given were 

 made south of the fiftieth degree of north latitude. 1 North of that parallel they 

 are cpiite full, though not entirely complete. Any omissions may, however, be 

 easily supplied, as the name of the observer, the point of the first appearance and 



1 In a wqrk recently published by the State of New York, entitled "Results of a Series of Meteoro- 

 logical Observations made in Obedience to Instructions from the Regents of the University of Sundry 

 Academies in the State of New York, from 1826 to 1850, inclusive, compiled by Franklin B. Hough, 

 M. D., Albany, 1S55," will be found a very full record of all auroras noticed in New York within the 

 limits mentioned. I would also refer to various professed treatises on the subject, and especially to the 

 volume on Auroras published in the Reports of the French " Commission Seientifique du Nord en 

 Skandinavie, Laponie, &c." 



