30 APPENDIX. 



tlie vertical force was observed, it was found less than the normal, at 20 h 36 m depression 20 divisions, 

 at O h 23 m it was 31 divisions or 0.001 parts of the force below the standard value. 



XIII. 1843, June 21th. At 22 b a bright -diffused light to north, particularly bright to N. W., 

 whence streamers are shooting up; general light weakens as it rises at 20 b 45 m ; at 21 h 15 m a brilliant 

 light, dark cumulus spots in the bright light, and long streaks of dark clouds to N. Fades at 22 h 1 3 m , 

 light to N. faint ; dark, fuzzy, low cumuli form and disappear to N. Neither the declination nor the 

 horizontal force was disturbed by this aurora. The vertical force was slightly affected, force less 38 

 divisions or 0.0012 parts of the force. 



XIV. 1843, June 30th. At 23 h aurora visible to the N. N. E., flaming to about 10. The 

 declination disturbances commenced at 22 h 20 m (9 divisions W.), they reach a maximum at O h 02 m 

 (July 1st) of 20 divisions (9'), and gradually disappear, the deflections having been west throughout. 

 The horizontal force is smaller than the normal value, a first minimum is reached about 20 h 44 m 

 (about 45 divisions), and the principal minimum about O h 10 m (July 1st) of nearly 50 divisions (0.0018 

 parts of the force). The vertical force remained undisturbed. 



XV. 1843, July 7th. At 20" 52 m very light in the N. N. E. and N. W. The declinatio'n at 18 h 

 20 m is deflected 15 divisions E., the motion then became westerly and reached 29 divisions (13') W. 

 at 23" 33 m ; at 2 h 20 m (8th) the deflection is again 16 divisions W. The horizontal force is less than 

 usual, with a minimum value about 20 h 52 m of 55 divisions (0.002 parts). The force then increases, 

 and about midnight reaches slightly above the normal. The vertical force was not disturbed. 



XVI. 1843, July 24th and 25th. According to a letter (dated July 25th) from one of the obser- 

 vers, auroral disturbances commenced about 16 h (July 24th) and quieted down about 21 h . At 16 h 

 20 m the declinometer was deflected 15 divisions E., about 4 h (25th) the disturbances reappeared 

 deflecting 10 divisions W., and changed to east deflection at 6 h 20 m , reaching a maximum east of 34 

 divisions (15') at 13 h 20 m . At 16 h 22 m the horizontal force was about 46 divisions less, with dis- 

 turbances reappearing about 8 h 22 m , reaching at 8 h 46 m 96 divisions (0.0015 parts of the force) below 

 the normal, and quieting down about one hour after noon. The vertical force was not sensibly 

 disturbed 



XVII. 1843, July 25th. At 21 h 30 m (25th) streamers to N., flaming to about 30 ; at 22" streamers 

 very bright, reaching about 40; At 22 h 15 m light very faint and gradually disappearing. The 

 declination was disturbed (deflections west) between 20 h 20 m and 22 h 20 m reaching a maximum at 

 21 h 58 m of 36 divisions (16'). The horizontal force decreased between 18 h 22 m and 22 h 22 m ,reach- 

 ing at 21 h 34 m 91 divisions (0.0033 parts) below the normal value. The vertical force apparently 

 undisturbed. 



XVIII. 1843, August 22d. At 20 h 22 m there were streamers of 35 in length, bright light in N. 

 Between 14 h 20 m and 18 h 20 m there was a small east deflection of the magnet reaching 28 divisions 

 at the latter hour; at 19 k 56 m it changed to a west deflection of the same amount (13'). At the time 

 of the appearance of the streamers the declination was normal. During the aurora the horizontal 

 force diminished, reaching at 20 U 28 m 91 divisions (0.0033 parts) brlmv the normal. The low value 

 continued for about two hours after this time. The vertical force was not sensibly affected. 



XIX. 1844, January 24th and 25th. Aurora visible to N. and N. N. E. at O h 22 m (25th), streamers 

 running up 30; O h 33 m streamers running up 15 and 20. During this aurora the horizontal needle 

 was deflected to the westward about 10 divisions, reaching a maximum at 6 h 58 m of 15 divisions (7') ; 

 at the time of the appearance of the shorter streamers the deflection was near 7', the horizontal force 

 was below the normal value, viz: decrease 36 divisions, 41 and 35 divisions at 22 h 22 m , 23 h 22 m , and 

 O h 22 m (25th), minimum 47 divisions (0.0017 parts). At the time of the longer streamers there was 

 an average decrease, and during the continuance of the shorter streamers the horizontal force was 



