Date. 



Hour. 



1839, May 20, 



9— 11, A.M. 



H li 



(( «c 



6 OBSERVATIONS TO DETERMINE THE MAGNETIC DIP, ETC. 



Magnetic Dip at Sandusky City, Ohio. Latitude 41° 29' N.; Longitude 82° 48' TV. 

 Place of observation an open field, a few rods soutii of the village. 



Jfeedle. No. Readings. Observed Dip. 

 No. 1 80 73° O'-O 



2 80 72 55-6 



Mean of 160 observations with two needles, 72 57 '8 



From the preceding observations, compared with such as have been made 

 in other parts of the United States, and of which a collection may be seen in 

 the American Journal of Science, Vol. xxxiv. p. 308, it will appear that the 

 same dip is found in a higher latitude in the western than in the eastern states. 

 The lines of equal dip, consequently, intersect the parallels of latitude, their 

 direction being from about N. 82° W. to S. 82° E. 



