Miscellanies. 183 
The connexion between heat and cold, and the magnetic phenom- 
ena, is shown by numerous facts, and could any plausible solution be 
offered for the phenomena of magnetism by the different states of 
temperature of the earth, and of the probable composition of terres- 
trial bodies, it would be more accordant with what we observe in na- 
ture, than in supposing four revolving magnets in the interior of the 
arth. : : 
There are facts which seem to favor the following positions. 
1. That the coldest points in the northern hemisphere are the mag- 
netic poles, and that these in all probability lie under the arctic cireles. 
2. That the poles of the magnet in passing from the northern to 
the southern or from the southern to the northern hemisphere are re- 
versed, by the magnetism of one end of the needle passing to the other. 
I would be glad to learn how far you think these suppositions prob- 
able, or whether their fallacy can be shown from any thing yet known. 
Very respectfully your obedient servant, 
J. Hamiiton. 
To Prof. Silliman. 
Carlisle, Penn. February 27th, 1832. 
It is not in our power to add any thing precise in answer to the 
inquiries of Mr. Hamilton, and we therefore invite the observations 
of others.—Ed. 
17. “ List of officers of the Academy of Natural Sciences of Phil- 
adelphia for the year 1832.”—President, William Maclure. Vice 
Presidents, George Ord, William Hembel. Corresponding Secre- 
tary, Samuel George Morton, M.D. Recording Secretary, 'Thom- 
as M’Euen, M. D. Librarian, Charles Pickering, M. D. Treas- 
urer, George W. Carpenter. Curators, J. P. Wetherill, S. G. Mor- 
ton, M. D., Thos. M’Euen, M. D., and Charles A. Poulson. 
Philadelphia, Feb. 16, 1832. 
18. Amos Dooxarrie the earliest American Engraver.—Be- 
tween the present and the preceding No. of this Journal our vene- 
rable old engraver, Mr. Doolittle, has descended to the tomb, nor are 
we willing that his name should float away on the tide of time, with- 
out a passing notice. He has often assured me that he was the 
first person who engraved on copper in this country and this assu- 
rance he repeated a short time before his death. 
