106 



RECORD AND RESULTS OP 





Set 4. 



Deflections. Distance 1.3 foot. 



Septembei 



7, 1861. 



E. 



E. 

 W. 



2330 43' 40" 

 216 23 10 



44' 10" 

 23 20 



45° 

 44 



2m = 17° 20' 40" 



W. 



E. 

 W. 



234 10 00 

 215 31 40 



11 00 

 32 10 



40 

 40 



2tt = 18 38 35 







Mean. 



42.2 



u^ 8 59 49 



Correcting for torsion and for difference of temperature we find 



hence ^=1.763 and 1.762 

 IgmX =9.73564 9.73622 



and 



= 0.309 



at 46° 



0.309 



at 42° 





Recapitulation of Preceding Values 



01 Horizontal Force. 





No. 



Locality. 



Latitude. 



Longitude. 



X 



Date. 



Observer. 



1 



2 

 3 

 4 



5 

 6 



7 



Cambridge, Mass. . . . 

 Proven, North Greenland 

 Port Poullie, Smith Strait 

 Netlik, Whale Sound . . 

 Upernavik, N. Greenland 

 Godhavn, Disco, " 

 Washington, D. C, U. S. 



42° 23' 

 72 23 

 . 78 18 

 77 08 

 72 47 

 69 12 

 38 53 



71° 07 



55 33 

 73 00 

 71 22 



56 03 

 53 28 

 77 00 



3.607 

 1.576 

 1.084 

 1.110 

 1.358 

 1.762 

 4.296 



July, 1860 

 Aug. 1860 

 July, 1861 

 Aug. 1861 

 Aug. 1861 

 Sept. 1861 

 June, 1862 



A. Sonntag 

 A. Sonntag 

 H. G. Radcliff 

 H. G. Radcliff 

 H. G. Radcliff 

 H. G. Radcliff 

 C. A. Schott 



The horizontal component Jl of tlie magnetic force is expressed in English units 

 (feet and grains). 



To the above two stations (Port FouUie and NetHli) at and near Smith Strait, I 

 have added the following three stations occupied for horizontal force by Dr. Kane's 

 party in 1854 and 1855. 



Van Rensselaer Harbor, $ = 78° 37' ji,= 70O53' A' =1.139 (1854) 



Hakluyt Island, 77 23 73 10 1.344 (1855) 



Near Cape York, 76 03 68 00 1.573 (1855) 



The observed horizontal force H, at these five stations, is represented by the formula 

 H= 1.250 —0.11 A^ —0.21 A;1 cos ^ 

 where A(p = ^ — 77°.50 and A?. = 2. — 71°.29 

 It was found, however, that the determination at Hakluyt Island, where the 

 horizontal force appears too large, had the effect of inclining the isodynamic lines 

 more than was warranted by values of more southern stations. I have, therefore, 

 given tlie determination at Hakluyt the weight one-half, and find 



H= 1.250 —0.07 A^ —0.30 A;i cos ^ 

 by means of which equation the isodynamic lines of 1.0, 1.1, 1.2, 1.3, and 1.4 were 

 laid down on the chart. 



The observations are represented as follows : — 



Obs. H. 

 PortFoulke 1.084 



Netlik 



Van Rensselaer Harbor 



Hakluyt 



Near Cape York 



The probable error of a single representation is ±0.10, and of any resulting 

 line +0.05 nearly. 



1.110 

 1.139 

 1.344 

 1.573 



Comp. H. 

 1.089 

 1.270 

 1.196 

 1.132 

 1.588 



DifiF. 

 —0.005 

 —0.160 

 —0.057 

 + 0.212 

 —0.015 



