700 



TEKRESTRIAL MAGNETISM. 



These observations of Horizontal Force made by Drs. Kane and 

 Hayes are compared with what seems to be the absolute vakie of 

 the Horizontal Force, 3 • 607, for the same period at Cambridge, 

 Massachusetts ; in which case the Total Force at Port Foulke is 

 12 "56, and at Van Rensselaer 12*38 British absolute units, ac- 

 cording to the system adopted by Sir Edward Sabine in his Mag- 

 netic Survey of the Earth. 



The inclination was obtained at five stations in the neighbour- 

 hood of Smith Sound by means of a dip circle, and the deter- 

 minations were made with each of two needles. In the following 

 table they are compared with three determinations from Dr. Kane's 

 Expedition in 1853-54, and with observations made at Port 

 Kennedy and at Polaris Bay. 



Observed Inclination. 



Date. 



Locality. 



Lat. 



Long. 



Observed 

 Dip. 



Declina- Hor. 

 tion. Porce. 



Aug. and 



Sept. 1861 



July 1861 - 



Aug. 1861 



Aug. 1853 • 

 Sept. „ • 

 June 1854c 



Nov. 1858 ■ 



Godliavn, Disco Is- 

 land. 

 Port Foulke, Smith 



Str. 

 Littleton Island 

 Gale Pt., CcTdogan 



Inlet. 

 Hakluyt Island, off 



Whale Sound. 

 Netlik, Whale Sound 

 Cape Grinnell - 

 Marshall Bay - 

 Van Rensselaer Har- 

 bour. 

 Port Kennedy - 

 Polaris Bay 



6°9 12 



5°3 28 



78 18 



73 



78 22 

 78 11 



73 30 



76 28 



77 23 



73 10 



77 8 



78 34 

 78 51 

 78 37 



71 22 

 71 34 

 68 54 

 70 53 



72°0'49" 

 81° 31' 



94° 19' W. 



61° 44' 



81 51 

 85 3 



84 43 



85 21 



85 



84 58 



85 8 

 84 49 

 84 46 



8° 27' 4" 

 84° 23' 



111 40W. 



106 49W, 



108 12 



135 47 



96° 00' 



1-762 

 1-084 



1-344 (P) 

 1-110 



9. Hourly Observations of Magnetic Declination, by Capt. 

 R. Maguire and the Officers of H.M.S. " Plover," in 

 1852-54, at Point Barrow. Phil. Trans., 1857, p. 497. 



The instruments used were two dip circles, one of 9\ inches, 

 the other of 6 inches, each with two needles ; and a portable decli- 

 nometer having a perforated magnet of 3 inches in length, carrying 

 a collimator scale in the interior, the divisions of which were read 

 by a detached telescope. 



The Observatory was composed of an outer house of ice 12 feet 

 square and 7 feet high, within which was another of sealskin 

 7 feet by 6. Two posts 23 inches apart were then sunk, and 

 being firmly frozen into the earth served as supports for the 

 declinometer and telescope, whilst another post was placed in the 

 N. W. corner for the chronometer, and a pedestal was placed outside 

 the Observatory for the dip circle, which was afterwards removed 

 to another house 15 feet N.W. of the Observatory. 



The dip was observed twice a week. Two dipping needles were 

 broken through awkward handling owing to the extreme cold. 



