634 



APPENDIX. [No. IV. 



Rein-deer and other islands on the northern side of the lake, and cause the increase 

 of variation which we have observed. 



Departing 



no material change in the variation took place 

 for the distance of seventy-six miles on N. 3° E. course ; but on advancing sixteen 

 miles further on a N. 27° E. course to Upper Carp Lake, the variation increased 

 4° 15'. It continued stationary until we reached the portage next beyond Grizzle 

 Bear Lake, a distance of thirty miles, but decreased a degree between that place and 

 Fort Enterorise. a distance of thirteen miles N. 8 W. true. 



It may be remarked, that from the time we left Fort Providence, we travelled 



rough a country composed of primitive rocks. 



The proportional increase of variation in a degree of longitude, were in different 



quarters as follows: 



Long 



2° 37' ; between Jack River and Hill Gates, 55 J minutes ; between Hill Gates and 

 Norway House, 54| minutes ; between Norway House and Cumberland, 41 J minutes ; 

 between Cumberland and Carlton House, 54J minutes ; between Carlton and Green 

 Lake, 58 minutes ; and between the Methye Lake and the Forks of the Athabasca 



River, 50 minutes. 



We found a considerable increase in the amount of variation between the obser- 



■ 



vations made at Fort Enterprise in the autumn of 1820 and the spring of 1821, as 

 shewn both by Kater's compass and the needle attached to the transit instrument. 

 Being at a loss to assign any other cause for these differences than a change in the 

 poles of the needles during the interval, I shall state the particulars to enable others 

 more conversant in these matters, to judge for themselves. 



On August 21st, 1820, the variation shewn by Kater's compass, No. 2, which then 

 agreed with No. 1, was 35° 48' 21" E. at four P.M. In the months of May 

 and June 1821, it was ascertained to be 36° 24' 7" E. by means of several obser- 

 vations obtained between four and six P.M. with Kater's compass, No. 1, being 

 an increase of 35' 46". On the 4th September 1820, the variation was 36° 15' E., 

 as shewn at noon by the needle of the transit instrument ; and in the months of May 

 and June, it was ascertained to be 37° 24' E., by the means of several observa- 

 tions with the latter needle, making an increase of 1° 9 1 from last observation. 



w 



It should be observed that the compass No. 2, received some injury in the course 

 of the winter, which was the cause of its not having been used in the spring of 1821 . 



The results of the azimuths 



Mine 



River, follow the course which we had previously observed them to take, by shewinr 

 an increased easterly variation, as we proceeded to the north and westward. There 

 was not, however, such regularity in the increase as to enable us to form any judg- 



lines of variation make in these latitudes ; and I 



ment 



deem it unfortunate that a continuation of cloudy weather prevented us from ob- 



