MAGNETIC FORCE. 



3 



Mag 



needle was brought to a horizontal position by a magnet, and being then permitted to swing freely, the number of vibrations were 

 counted, and the time noted until it rested and pointed to a degree on the graduated circle, which is called the Arc in the table. 

 The interval shews the time that it did vibrate, and the next column the number of vibrations. 



The instrument was not of the best kind for making with accuracy such delicate observations, and our results may, perhaps, be 

 considered as only approximations to the truth. 



L 



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TABLE IX, 



Date 



Latitude 

 North 



1819 



Nov. 24 



Dec. 1 



1820 



June 29 



o 



// 



Longitude 

 West 



o 



53 56 40 102 16 31 



55 26 45 



July 956 43 



Z 



14 



Aug. 1 

 30 



1821 



June 9 



July 31 



58 42 38 

 62 17 19 



64 28 2! 



67 19 23 



107 52 45 



109 53 



111 18 55 



114 9 34 

 113 6 00 





109 44 30 



An Abstract of Observations on the Magnetic Force. 



Face of the Instrument East 



Arcs 



Inter 

 val 





o / 

 78 00 



77 40 

 76 45 



8 47 



9 15 



9 29 



77 08 



SO 47 



13 19 



82 25 



83 50 

 83 15 



11 50 



12 26 



9 45 



11 57 



9 46 



86 55 



7 48 



No. of 

 Vibrations 



140 

 140 



143 



188 



170 



140 

 155 



133 



8 48 123 



113 



Interval 

 of 10 



Vibrations 



37,6 

 39.6 



39.8 



42.6 



42.1 



41.8 

 46.3 



44.1 



42.9 



41.4 



Face of the Instrument West 



Arcs 



o / 



89 50 

 89 50 



89 45 



Inter- 

 val 



No. of 

 Vibrations 



/ // 

 8 47 



8 47 



87 55 



88 45 



9 5 







10 40 





87 35 

 89 10 



11 555 



9 33 

 12 39 



89 30 11 45 



90 05 



96 30 



12 10 



40,5 



^ 40 8 36 



130 

 130 



140 



149 



169 



136 



190 



160 

 173 



94 



124 



Interval 



of 10 

 Vibrations 



40.5 

 40.5 



41.3 



40.3 



42.3 



42.1 

 40.0 

 44.1 



42.6 



41.6 





Face of the Instrument West 



Arcs 



O , 

 85 20 



84 50 



Inter 

 val 



» 



No. of 

 Vibrations 



, // 



8 40 



9 04 



130 

 136 



86 20 



87 00 

 93 30 

 81 10 



Face of 



97 48 



88 20 



9 41.3 

 13 18 

 10 37 



7 11 



the In 

 9 11.5 



9 51 



150 

 200 

 162 



100 



strum ent 



124 



150 



Interval 



of 10 

 Vibrations 



// 

 40,0 



40.1 



Temperature 

 of the Air 





38.8 

 39.9 

 39.9 



43.1 



South 



44.5 



In a room at Cum- 

 berland-House 



In the air at Cumber- 

 land-House 



Isle k la Crosse, by 

 Mr. Hood 



Methye Portage, by 

 Mr. Hood 



Fort Chipewyan 



Fort Providence + 72 



+24 room 

 —15 air 



+ 29 



+ 68 



+ 62 

 + 68 



Fort Enterprise 



39 



•M 



Fort Enterprise 



First Cascade in 

 Hood's River 



+ 55 



+ 73 

 + 63 





o 





