No. III. 



OBSERVATIONS ON THE AURORA 



AT FORT ENTERPRISE, 

 EXTRACTED PROM THE JOURNAL OF CAPTAIN FRANKLIN. 



The forms of the Aurora Borealis, during the winter, have been so various 

 and fleeting, that it is impossible to comprehend them in a general outline ; 

 and the inferences I have drawn on a subject, respecting which I had not pre- 

 pared my mind by previous study, are offered with diffidence ; but I hope the 

 observations of the position of the needle, given in the following tables, may, 

 together with those, made with great attention by Mr. Hood, be found useful to 

 such persons as are more conversant with such inquiries. 



The horizontal compass was placed in a firm-sheltered stand, fixed to the 

 back wall of the house, three feet above the ground, on a northern exposure, 

 and the dipping needle was similarly fixed to the end of the store-house, at the 

 distance of forty feet. There was no iron near either of them, the house- stands 

 on a sand hill, and there were no large stones in its immediate vicinity 0 *. 



The horizontal compass belonged to a small variation transit, made by Dol- 

 lond ; and its graduated circle of one and a half inch radius, is divided into de- 

 grees, the degrees counting from the north towards the, west to three hundred and 

 sixty. Each degree is sub-divided to twenty, but by the assistance of a mag- 

 nifying glass, I could read off accurately, to within three minutes. The hori- 

 zontal position was preserved by means of a spirit level attached to the instru- 



* The Rater's Compass, with which Mr. Hood made his observations, was fixed in a room on the 

 opposite side of the house, close to a parchment window that admitted the air, and it was about 

 twenty-four feet apart from the horizontal compass. 



