154 J. H. Lefroy on the Aurora Borealis of 1850-1851. 
cially naming here those of Mr. Swanston, Mr. Clouston, and 
Mr. Anderson ; the first of these is a model of completeness and 
conciseness, Mr. Swanston having generally recorded the state of 
the sky and the weather every hour from dark to 10 p. m., and in 
terms which are always definite and expressive. 
The registers have been continued at the Military Guardrooms 
the Royal Artillery in Canada, and at a great number of sta- 
bservation in the United States. I have now in my 
of 
sonian Institution, returns from upwards of an hundred 
through all the States, from the Atlantic to the Mississippi. Not 
having received observations from any of the stations on the 
Saskatchawan, or Lake Winnipeg, there is a pretty wide blank, 
extending from Lake Athabasca to Lake Superior, in the chain 
by which it was hoped to trace and identify, displays from the 
polar circle downward to Canada, but 
at least of the intermediate posts will: oblige me with a journal : 
and if each observer will bear in mind that others, hundreds, and 
tion of familiar descriptions might otherwise afford. te 
_It has been often stated vaguely that aurora appears every clear 
night. This is certainly not true of any One station, as far as the 
earlier hours are concerned, we are still short of proof that it is 
true in the widest meaning ; indeed, the statement, if true, would 
carry little weight with it, without the addition of dates, facts, 
February, 1852. The display of February 18th, 1851, was one of 
a einen eerie wc ee ee : Ee a See Ce DP renee 
* Every night but two, February 2 and 16. 
