Variation and Dip of the Magnetic Needle. 293 



laid before congress, by Mr. Shaw of Maryland. This represen- 

 tation was referred to the consideration of a committee of the 

 House of Representatives, of which Mr. Pitkin was chairman. 

 The committee deemed the subject of sufficient importance to 

 merit investigation, and accordingly directed circular letters to 

 men of science in different parts of the country, requesting infor- 

 mation on the present declination of the magnetic needle. The 

 answers to these circulars embodied considerable information of 

 which the following is a summary. 



President Wheelock of Dartmouth College, New Hampshire, 

 states that in 1765, the declination of the needle was at Hanover 

 about 7° W. ; at present (1810) 4° 15' W. 



James Whitlaw, a surveyor in Ryegate, Vermont, lat. 44° 10' N. 

 and long. 72° 10' W., states the declination at that place in 1801 to 

 have been nearly 7° W. 



President Messer of Brown University, Rhode Island, states 

 the variation there in 1769 at 6|° W. ; but in 1790 it was, if the 

 variation compass made use of could be relied on, only 3° 46' W. 

 [I have myself italicised the above clause to intimate my convic- 

 tion that there must have been some error in this observation, or 

 else that the compass did not in both instances occupy the same 

 spot. It is not credible that the needle had changed 2|° in twenty 

 one years. — E. L.] 



Mr. Asher Miller of Middletown, Conn., states the variation at 

 Danbury for 1810, at 5° 41' W. ; at Lyme 4° 30' ; Pomfret 5° 5' ; 

 Hebron 4° 50' ; East Hartford 4° 46'. 



President Smith of Princeton College, New Jersey, gives the 

 variation at that place for 1810 at 7° W. 



Andrew Ellicott, surveyor of the United States, gives the va- 

 riation of the needle at various pomts on the western boundary of 

 Pennsylvania. But as these observations are published in the 

 Memoirs of the American Philosophical Society, they are not here 

 repeated. Mr. Ellicott adds however, " the line of no variation in 

 the United States at present, (1810,) crosses the west boundary 

 of Pennsylvania, about thirty miles south of Lake Erie, and enters 

 that lake near to Presque Isle." 



Nicholas King, public surveyor, states the variation at Wash- 

 ington, Dec. 23, 1809, to have been 52' W. 



Bishop Madison of William and Mary's College, Williamsburg, 

 Virginia, lat, 37° 15', long. 76° 35', states the variation there to 



