APPENDIX. 625 



No. VIII. 

 MAGNETICAL OBSERVATIONS. 



During the progress of the expedition every oppor- 

 tunity was embraced of making the magnetical observ- 

 ations requisite for the determination of the dip and of 

 the variation of the needle, and of the terrestrial mag- 

 netic intensity. At Fort Reliance, such observations 

 were repeated on several occasions ; and a series of ob- 

 servations was also instituted for determining the diurnal 

 variation of the needle, and for ascertaining how far 

 extraordinary changes in its direction might be attri- 

 butable to the influence of the Aurora Borealis. 



These observations have been placed in the hands of 

 Professor Christie, who proposes discussing most of 

 them in a paper shortly to be laid before the Royal 

 Society. It will, therefore, be unnecessary here to 

 enter into their details. As, however, some of the im- 

 mediate results may be interesting, they are given in 

 the following tables. 



The Dip and Variation of the Magnetic Needle. 



The dip was determined by means of a small but 

 accurate dipping instrument, by Dollond, having a 



S S 



