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[Assembly 
dency of the needle, and render it entirely useless as an index to the 
true meridian. Nor would it be at all surprising, even where no local 
derangement might be apparent, should the needle be found to deviate 
some minutes, or even degrees, from the true magnetic north. Such a 
deviation, ascertained by experiment at different points, might furnish a 
valuable criterion by which to judge of the proximity of iron, of the di- 
rection of the bed or vein, and perhaps its extent. This might especial- 
ly be expected, were much of the iron (as is the case in this district) of 
that kind known under the name of the magnetic oxide. 
With views like these, although no provision has been made by the 
State for such experiments, it has been thought worth while to incur 
some private expense, with a view to determine whether any data of 
value could be ascertained by the aid of the needle. For this purpose, 
a small theodolite was procured, with a needle attached to it, and expe- 
riments made at several points, the results of which will be found an- 
nexed. It may be proper to premise, that the variation of the needle in 
this country at present is west^ at all points east of a certain line, called 
the line of no variation. This line traverses the western and southern 
States, and appears itself not to be stationary. East of this line, the 
variation is increasing; at least this is proved to be the case at several 
points where experiments have been make. 
At Williams College, in 1833, the variation was 6° 15' W. 
1837, " 7° 45' W. 
Showing an annual increase of 22' 30". 
The results annexed are deduced from observations made upon the 
pole star at its greatest elongation, and upon the sun at equal altitudes. 
The first station selected was at Crown Point, about two miles south 
of the old fortification. As no deposits of iron are known to occur 
near this point, it was imagined that the needle would be nearly free 
from the influence of local attraction. The variation from the pole star, 
at its greatest eastern elongation, was found at this place to be 10° 57'. 
Making the necessary corrections, we shall find the variation of the nee- 
dle from the meridian to be W. 8° 47'. This reduction supposes the 
latitude of the station to be 43° 55', which can vary but little from the 
truth. The next observation was made at Cedar Point, near Port Hen- 
ry, about six miles N. W. from the former station. Variation at this 
point, 9° 28'. At Moriah Four Corners, about two miles west, 10° 
10'. Proceeding still west, to a small pond, estimated at about six 
miles from the Corners, on the main road to West Moriah, the variation 
