APPENDIX VII. 



VARIATION OF THE COMPASS. 



The following list shows the variation of the compass in twenty-one 

 localities in the territory explored during the season. The observations 

 were taken with as much care as was possible while making such a 

 rapid survey of an extensive region, whei'e one had to attend, unaided, 

 to such a variety of different matters. The local attraction, which exists 

 in man} r places, especially among the Laurentian and Huronian rocks, 

 sometimes renders it difficult to ascertain the true variation for any 

 locality. Sir Henry Lefroy (who visited this region in 1843-44), in a 

 letter which I have received from him on this subject, says : — "I used 

 a new 7-inch compass, and used it carefully, but the results differ 

 much more than I can account for. This is particularly the case 

 where a change of geological formation occurs — say. for example, 

 about the narrows of Lake Winnipeg — and I should be greatly in- 

 terested in a good comparison by means of A.M. and P.M. sights on 

 the 'Dog's Head' and the 'Bull's Head,' and on the opposite side to 

 both. * * About Oxford Lake I have 12° 58', 10° 11', 14° 21', in 

 near proximity." Among other causes influencing the variation in 

 this region, besides that of change in geological formation on a large 

 scale, above alluded to, I have noticed beds of magnetic iron, deposits 

 of iron sand, dykes of diorite, great magnetic boulders, sudden change 

 in the general level in passing from one region to another, proximity 

 of a cliff or bank or even of a thick grove or (when very close) a 

 single large tree. 



Variation E. 



1. Little Churchill River, 24 miles south of its junction with the 



Great Churchill. (The north side of the " forks " being in 



lat. 57° 30' 57.34" and about long. 95° 30') 11" 30' 



2. Little Churchill River, 5 miles north of last 10° 30' 



3. At the north side of the junction of the Little with the Great 



Churchill River, in the above latitude 12° 30' 



4. Great Churchill River, 22 miles uorth of the above junction. . 15° 00' 



5. Great Churchill River, 27 miles from its mouth 6° 30' 



6. Fort Churchill, on the west side of the river, 4 or 5 miles from 



its mouth. (Lat. 58° 44' 43.04") 11° 00' 



