26 



OBSEKVATIONS ON 



Dip. 



Epoch of 

 commencing 

 vibration, 

 hrs. min. sec. 



Duration 



^ 



Calculated 



of 500 



ll 



duration 



vibra- 



at 60°. 



tions. 



H ^ 





Square of tlie 

 preceding. 



Horizon- 



Total in- 



tal inten- 



tensity : 



sity. 



hor. be- 





ing 1000. 



Total inten- 

 sity : that at 

 Cincinnati 

 = 1000. 



213. Near Double-Heart River.— Lat. 46° 43' N. Long. 85° 38' W. August 13, 1847. 



77° 31' 07" 



5 21 00 A 



5 50 08 



1636.0 

 1632.2 



64.5 

 66.5 



1F35.50 

 1L31.34 



26748602500 

 26616702056 



Mean 



682.13 

 677.41 



679.72 



3116.5 



1041.5 



214. Twomileswest of White Fish Point.— Lat. 46° 46' N. Long. 85° 13' W. August 

 13, 1847. 



77° 32' 00" 5 8 50 00.8 1639.6 65 1639 2686320000 679.22 3146.4 1051.6 



215. Little Taquamanon River.— Lat. 46° 41' N. Long. 85° 13' W. August 14, 1847. 



77° 19' 30" 5 4 46 00 1634.4 78 1632.47 26549583009 687.24 3132.1 1046.8 



216. 



St. Mary's River, opposite Palmer's.— Lat. 46° 32' N. Long. 84° 24' W. August 20 

 1847. 



77° 23' 15" 



33 15 

 02 03 



1637.1 

 1631.2 



69.5 

 66.5 



1637.01 

 1630.46 



26800964100 



26583998116 



Mean 



680.81 

 678.19 

 679.00 



3109.6 



1039.3 



217. Drummond's Island.— Lat. 46° 00' N. Long. 84° 03' W. August 25, 1847. 



77° 06' 34" 



11 48 03 

 11 26 00 



1623.6 

 1617.6 



79.5 

 79.0 



1621.44 26290376736 



1614.90)26079037636 



i Mean 



694.02 

 691.27 

 692.64 



104.5 



1037.6 



218. Bruce's Mine, at the landing— Lat. 46° 19' N. Long. 83° 58' W. August 22, 1847. 



77° 02' 32.5" 



6 28 02 

 6 47 03.8 



1624.6 

 1614.6 



1624.26 

 1614.60 



26382205476 



26069331600 



Mean 



691.60 

 691.54 

 691.58 3084.1 



1030.7 



219. Bruce's Mine, near the principal vein of ore. — August 23, 1847. 



77° 16' 00" 



6 16 02 A 



1649.6 



56 



1650.18 



27230940324 



I 

 662.04 13008.6 



1004.9 



220. Bruce's Mine, at the basaltic bluffs, 40 rods north of the mine. 



74° 24' 22" 



9 51 01 A 



1485.6 



1484.56 



22000371600 



819.43 



3049.5 



1019.2 



REMARKS. 



213. Near Double-Heart River. — Range 10, township 49, section 1. 



214. Two miles west of White Fish Point. — Range 6, township 51, section 31. 



215. Little Taquamanon River. — Range 6, township 49, section 3. 



216. St. Mary's River. — Range 2, township 48, section 29. 



217. Drummond's Island. — Range — , township 42, section 31. 



218. Bruce's Mine. — Geology : over a trappean dike, and near the lake. 

 220. Bruce's Mine. — Geology : pieces of basaltic rock, decidedly magnetic. 



