208 



Prof. W. A. Norton on Terrestrial Magnetism. 



pothetically the Asiatic pole in east longitude 160°, and lat. 65°, 

 and the American pole in west longitude 72°, and latitude 67°, 

 the declination came out very near the truth, and at the same 

 time the mean annual temperature, as computed from Brews- 

 ter's formula, by taking n=f, corresponded very closely with 



observation. 



was supposed that, as the temperature 



Asiatic was some 4° (Fahrenheit) higher than that of the Amer- 



ican 



hypothetical! y 



distance, and the latter perhaps brought nearer. But the neces- 

 sary changes of position, though lying in the direction thus sug- 

 gested, are apparently much too great to be reasonably attributed 

 to this cause. Upon making the calculations for other places, it 

 was found necessary in each instance to place the cold poles hy- 

 pothetically in positions more or less diiferent from their true po- 

 sitions. The computed declinations, compared with the observ- 

 ed, together with the supposed longitudes and polar 

 the two cold poles, are given in the following table. 



distances 



Table I. 



Place. 



London, 



Paris, 



Milan, 



Gottingen, 

 Berlin, 



Spitzbergen, 



Moscow, 



Tobolsk, 



Urga, 



Pekin, 



Stretensk, 



Jakutsk, 



Tschernoljes 

 The Azores, 

 New York, 



Washington, 

 Havana, 

 St. Louis, 

 Sitka, 



Longitude. 



Declination. 



Computed. 



24° 54' W. 



w. 

 w. 



16 in w. 



i4 3o w. 



o w. 



9 E. 

 6 E. 



Observed. 



24° o' W . 

 22 4 W. 



18 33 w. 

 18 48 w. 

 17 5 w. 



25 12 W. 

 O 8 E. 



Diff. 





IO 29 E. 



IO E.I I 16 E. 



1 w.j i 48 w. 



56 w. 2 52 w. 



6 3o w. 5 5o w. 



2 52 w. 3 3o w. 



24 n w.23 45. w. 



+o° 54' 

 +0 5 



+0 3o 

 -2 1 



-2 35 



-1 12 



American pole. 

 Lon. 



3 20 w. 

 29 w 



5 23 w. 



1 4r w. 



5 20 e. 5 3o e. 



8 27 E. 

 20 3o E. 



35 e. 

 5 5o e. 



O E. 



8 44 e. 



28 19 E.+I 



8 



7 



5 



O E. 

 O E. 

 O E. 



+0 1 



+0 3 7 



+0 54 

 o 47 

 o 56 



+0 4o 

 -o 35 



+0 26 



-2 3 



— O 12 



— O JO 



17 



IT 

 I 25 



1 5 

 o o 



72 w. 

 65 w. 

 65 w. 

 70 w. 

 70 w 



85 w. 



70 w. 



80 w. 



95 w. 



85 w. 



85 w. 

 no w. 

 no w. 



80 w. 



87 w. 



85 w. 



5o w. 



70 w. 



85 w. 

 83 w. 



86 w. 

 90 w 



Asiatic pole. 

 P. disLj 



1 ne ooserved declinations were taken from Gauss's table of 

 comparisons, Hansteen's table of declinations according to the 



Loomis 



determinations of declination for the United States by Gauss 



f s 



formul 



a 



observation, published in thp Nn nf this Journal 



case 



Equal Variation." 



1816. Norm nf t 



Barlow's " Chart of Magnetic C 



observation for Havana was 1 



er observations date more than 



