APPENDIX. 



597 



aurora ceasing, and the coruscations becoming faint, it 

 settled at 0° 30' E. 



October 28th. — At 8 h a.m. the needle was at 1° 20' 

 E. At 9 h I found it at 2° 20' E. : saw it move to 2° 50' E., 

 and being something surprised, I went out to endeavour 

 to trace some cause for such a deviation. There was 

 not, however, the least vestige of a cloud, the sky being 

 of an indigo colour at the zenith, and becoming fainter 

 in tone till it mingled in a pale yellow near the horizon. 

 The sun was very bright, about 10° high, and bore 

 E. J S. (m.) * The thermometer on the north side 

 of the observatory was — 4j°, that on the south, exposed 

 to the sun's rays, was + 4j° : the weather calm. 



At 10 h a. m. the needle was agitated at 1° 30' E. ; at 

 ll h I found it also at 1° 30' E., but in motion, which 

 took it to 2° 0' E., then to 0° 20' E., to 0° 20 W., 

 where it remained ten seconds, and repassed to 0° 40' E., 

 to 0° 0, 0° 10 E., to 0° 30' E., 0° 20' E., to 1° 0' E., 

 1° 40' E., and 0° 25' E. : when, seeming to be stationary, 

 I went out, and placing myself in the shade of a fir tree 

 of thirty feet high, looked directly to the zenith and to 

 the westward (the sun being too bright to look to the 

 eastward), when there appeared a very faint and filmy 

 arch of pale white, that issued from a mass of white 

 cloud precisely similar in shape to the horse-shoe mass 

 of aurora of last night in the same place ; and on watch- 



* All the bearings are magnetic. 



QQ 3 



