194 



Magnetism of the United States and its Vicinity 



\ 







Table II. — 



Continued. 











Station. 



1 Latitude. 



Longitude. 



J 

 | 72 c 



)ip. 



Intensity. 



Datf J 



Newark. .... 



4o° 43' 



74° 10' 



> 48'-5 



I'784 



1 w 



Wellsville, 







4o 38 



80 44 



72 



35-3 



1-794 



1 844 



Pittsburgh, . 







4o 32 



80 2 



72 



43-5 



i-8o3 



1841 



New Brunswick, 







4o 3o 



74 25 



72 



43-2 



1-785 



1 844 



Princeton. . 



* 







4o 22 



74 39 



72 



3 9 -5 



T-784 



m 



Trenton, 





! 4o i3 



74 4o 



71 



59 -o 



1790 



t84i 



Wheeling, . 







4o 8 



80 47 



72 



19-3 



i-8i3 ! 



1 844 



Bristol, 







4o. 6 



74 47 | 



| 72 



25 



1-768 1 



1842 



Philadelphia, 







39 57 



75 10 



72 



I 



1-784 j 



1842 



Chambersbunj, 







3 9 55 



77 4o 



7i 



57-1 



1-788 ; 



1842 



Ml. St. Marv's College. 





■ j 39 41 



77 18 



7t 



46-3 



1790 1 



1842 



Cumberland, 





39 39 



78 44 



7i 



36 -o 



1-789 



r844 



Baltimore, . 







39 j 7 



76 3 7 



71 



36 -8 



1-781 



1841 



Cincinnati, . 



^f ^r ^^ ■ 







3 9 6 



84 22 



70 



2.5-4 



1-795 



1842 



Washington, 







38 53 



77 I 



71 



22 «7 



1-786 



1 844 



Georgetown, 







38 53 



77 3 



71 



9 



190 



r-768 



i844 



Mount Vernon. . 



* 





38 4l 1 



77 7 



70 



55-5 1 



1-782 



1844I 



The observations of Capt. Lefroy were made in the execution 

 of a plan for a magnetic survey of a considerable portion of the 

 North American continent at the expense of the British govern- 

 ment. This survey was urged upon the British Association in 

 the year 1837, by Lieut. Colonel Sabine ; and m the year 1S39 

 he formed a plan to execute the survey in person, but being call- 

 ed upon to superintend the publication of the observations made 

 at the colonial observatories, the survey was subsequently entrus- 

 ted to Lieut, (since Captain) Lefroy. Lieut. Lefroy was provided 

 with an inclinometer of nine inches by Gambey ; a Fox's incli- 

 nometer of seven inches diameter ; a portable unifilar magnet- 

 ometer j an azimuth compass ; a portable declinometer ; a port- 

 able bifilar magnetometer; and a portable induction inclinometer. 



May 





proceeded by the way of Lakes Huron and Superior to the Late 

 of the Woods ; thence to York Factory on Hudson's Bay ; «» 

 thence to Lake Athabasca, where he spent the winter. In tb 



McKen 



spring of 1844, he 

 circle, and returned to Toronto near the close of the same year. 

 He thus passed directly over the region of greatest magnetic in- 

 tensity in the northern hemisphere. The following table con- 

 tains a summary of most of Capt. Lefroy's observations, anj 

 includes also a few observations by Messrs. Younghusband 



and Rae. 



Table III 



Station. 



Fort Good Hope, 

 Fort Norman, 

 Fort Simpson, 

 Fort Resolution, 

 Athabasca, . 

 Fort Vermilion, . 

 Pointe Br w lee, . 

 Pierre au Calumet, 



Latitude. 



66^76^ 



Longitude. 



64 

 61 



61 



58 



58 

 58 



5? 



3i 

 5i 

 10 

 43 



25 



7 

 24 



128 



124 

 121 



Ii3 



in 



116 

 in 

 in 



o 



3o f W. 



44 



25 



45 

 18 



i5 



25 



35 



82 

 82 

 81 

 82 

 81 

 80 

 81 

 81 



Djp_ jTntpnsig; 

 055/ r 802 



r8ol 

 1-829 



1-838 

 j-8n 

 r-852 

 i-o3 



34-3 

 52-3 



44-5 



3? *o 

 48 -o 



3o-6 



16 -8 



1 84 



,844 



5 



