290 Variation and Dip of the Magnetic Needle. 
Thus far, however, the reality of such sounds, in any latitude, 
is seriously questioned. The Aurora is a phenomenon well suited 
to terrify the ignorant, and thus predispose them to connect with 
it athousand marvels, which have no existence: and it may even 
so far excite the imaginations of the better informed, as to inca- 
pacitate them fairly to judge of the fact; since for the most part, 
their impressions are previously formed. 
The world is, after all, very much in the dark, in regard to all 
that relates to this wonderful phenomenon. It is perhaps some- 
what doubtful, whether, in our day, this darkness is to be enlight- 
ened. We certainly live in a remarkable era, as it respects the 
frequency and the splendor of auroral exhibitions; and the phi- 
losophers of the present time will grievously neglect their duty, 
if they fail to take every possible advantage of the opportunities 
of observation, which alin are so happy as to enjoy. 
New Haven, Conn., Feb. 22,1 
Arr. I[1.—On the Variation and Dip of the Magnetic Needle 
in different parts of the United States; by Ex1as Loomis, Pro- 
fessor of Mathematics and Natural Philosophy i in Western wei 
— ge 
Asour three years ago, ¥ formed the design of collecting as far 
as possible all the observations which had ever been made on the 
variation of the magnetic needle within the limits of the United 
States. I was of opinion that such a work would contribute 
something to the cause of science, and might also be of practical 
utility to public surveyors, who very generally in this country 
make use of the magnetic needle in their surveys. ‘The Connec- 
ticut Academy of Arts and Sciences, gave me permission to write 
in their name to gentlemen in different parts of the country Te- 
questing information on the subject. A great number of letters 
Were written, and to most of them, answers have been received. 
The amount of information they embodied was not so great as 
had been expected. I therefore hesitated about prosecuting my 
original plan, and this, together with an absence of more than 2 
year from the country, is the reason that those observations have 
notsooner been made public. Although the article which is here 
presented is very imperfect, eiegesotilot the number, ane 
