296 Variation and Dip of the Magnetic Needle. 
in the Eastern States with which he was acquainted ; and in the 
Memoirs of the American Philosophical Society, as well as im 
those of the American Academy, various observations are recorded, 
The substance of all of these is given in the general table which 
follows. 
In the Aurora, a paper published at Philadelphia, July 27, 1813, 
is a communication from David M’Clure, stating the variation in 
Philadelphia at that time to be 2° 25’ W. In the same paper for 
Sept. 12th, is a communication from Thomas Whitney, mathe- 
matical instrument maker, stating the following facts. It ap- 
pears that the variation was here 8° 30’ W. in 1710. In 1798, it 
was observed by R. Brooks to be 1° 30’ W. In 1804, it was ob- 
served by several men of science to be 2° W. An anonymous 
- communication in the same Journal for Sept. 15th, states the va- 
riation at Lewis, in Delaware, in 1795, to have been 55’ west. _ 
The following facts I have learned from various sources. Mr. 
N. Goodwin, surveyor in Hartford, Ct., determined the variation 
at that place in 1824, to be 5° 45’ W.; in 1828, 6° 3’ W.; and 
in 1829, 6° 3’W. He also deterrained the variation in New Ha- 
ven for 1828 to be 5° 17’ W. 
The variation at Pensacola, Florida, was stated to me in 1835, 
by an officer of the navy, to be 6° E. 
The variation for New York is given at 4° 40’ W. in 1824, 
on Blunt’s map of that year. 
The variation at New Haven is also given at 5° 10 W. in 1811, 
on a map of that city. 
The variation at Montpelier, Vt., in 1829, was 12°25’ W., as 
given in Executive Documents, Vol. IV, No. 190, page 23. 
Variation at Kaskaskia, Ill., in 1809, 7° 20’ E., according to 
American State Papers—Public Lands, Vol. II, page 195. 
Variation at Alton, Ill., was given me at 8° E. in 1835. 
Variation at Athens, Ga., in 1837, 4° 31’ E., as determined by 
Prof. McCay. 
Variation at South Hanover, Indiana, in 1837, 4° 35/ E., as de- 
termined by Prof. Dunn. 
Variation at West Chester, Pa., in 1832, was 3° 25’ W., as ob- 
served by Prof. Bache. 
The Annual Report of the Regents of the University of the 
State of New York for 1837, contains the observations made at 
eleven different places in the State. ‘These are all all to be found in 
our general table. 
