28 



OBSERVATIONS ON 



CLASSIFICATION AND COMPARISON OF THE PRECEDING RESULTS. 



Kewenon Peninsula. 





Latitude. 



Longitude. 



Total Intensity. 



Fort Wilkins 

 Horseshoe Harbor 



Eagle River Mine 



u 



« 

 Cliff Mine ..'..' 



Copper Falls 



Baite du Oris 



Sibley's Mine 



Bohemian Mountain 



Mendelbaum's 



Landing near Sibley's . 



Mount Houghton . 



Western Point of Baite du Gris 



Point Kewenon . 



Hawk's Bill 



Mouth of Portage River 



Anse ..... 









47° 28' 00" 

 47 28 00 

 47 24 00 

 47 24 00 

 47 24 00 

 47 24 00 

 47 24 00 

 47 27 00 

 47 26 50 

 47 24 00 

 47 24 00 

 47 25 00 

 47 24 00 

 47 23 40 

 47 25 00 

 47 22 00 

 47 26 00 

 47 28 00 

 47 11 00 

 47 01 00 

 46 49 00 



88° 00' 45" 



87 57 00 



88 25 00 

 88 24 45 

 88 26 00 

 88 28 00 

 88 28 00 

 88 12 00 

 88 12 00 

 88 06 00 

 88 08 00 

 88 08 00 

 88- 08 00 

 88 08 00 

 88 04 00 

 87 51 00 

 87 50 00 

 87 50 00 

 87 30 00 

 87 30 00 

 87 34 00 



1149.6 

 1046.9 

 1038.7 

 1048.1 

 1050.1 

 1025.4 

 1039.8 

 1044.6 

 1083.2 

 1041.1 

 1058.5 

 1464.6 

 1182.4 

 1030.0 

 1052.5 

 1048.1 

 1077.1 

 1035.7 

 1030.3 

 1035.6 

 1036.7 



Mean 



47 22 36 



88 12 24 



1077.1 



Total intensity reduced to arbitrary 



scale 





1.9334 



BEMAKKS. 

 In April, 1844, I announced to the American Philosophical Society that, at Point Kewenon, I had 

 probably reached the place or region of maximum intensity; at the same time qualifying that announce- 

 ment on account of the want of more extended and multiplied research. 



Since Capt. Lefroy has examined the region between Lake Superior and Hudson's 

 Bay, Col. Sabine has calculated the maximum to be 1.878, and situated in latitude 

 52° 19' and longitude 91° 59'. 



The high intensity of Point Kewenon — determined by numerous observations 

 made over a region of thirty miles in extent — ^must, then, be considered a case of 

 extraordinary and extensive local attraction, the mean being higher than Col. 

 Sabine's maximum. Indeed, the abrupt changes and extraordinary results along 

 the trappean dikes and near the metallic veins are sufficient evidence of unusual 

 magnetic forces, although they operate on a scale coextensive with the peculiar 

 geological formations of trap and metalliferous conglomerate, occupying so large a 

 portion of that peninsula. 



If, however, we select such observations as were made on the horizontally-strati- 

 fied sandstone of the peninsula, we find them not only consistent among themselves, 

 but conforming to the results which Capt. Lefroy obtained between Lake Superior 

 and Hudson's Bay. They are as follows : — 



