irOTES TO THE ExTRA OBSERVATIONS OF MAGNETOMETERS, SEPTEMBER 21 — DECEMBER 8, 1846. 343 



NOTES ON THE AURORA BOREALES SEEN AT MAKERSTOUN. 



Gbtt. M. T. 

 d. h. m. 



^pt. 21 13 0. Aurora to N., consisting chiefly of patches of light and bundles of streamers to an altitude of 40°, 

 with incessant pulsation throughout the whole extent of the aurora ; the aurora is not very 

 bright, and it is obscured to a considerable extent by a black mass of clouds. 

 \ 15. No matei'ial change in the aurora ; it has a very confused appearance ; — an indescribable mass of 



i bundles of streamers and patches, with incessant and rapid pulsation. 



13 30. Aurora become fainter. 

 (it. 8 8 20. Auroral light ; feint streamers to N. and NW. 

 t. 9 8 5. Several bright streamers sprung up from NNW. 

 t. 22 10 Faint auroral light seen through an opening in the clouds 1 



I'lV. 17 7 34. Bright aurora over the sky ; partially cloudy ; quite overcast a little ago. A portion of an arch to 

 south, perhaps 30° (■?) altitude from SSE. 

 36. About this minute a bright patch of auroral light seen to ESE., altitude about 30°. 

 41. Broad streak of aurora reaching from SW. to SSW. ; altitude of the middle of the streak at its ter- 

 mination in azimuth S 20° W, is 18°. DiflFused auroral light, mixed with cirrous clouds ; hazy 

 and dark spaces ; difBcult to say where the aurora is bounded, or whether it be cut off by clouds. 

 43. The aurora forms a bay to SW. ; bright to NE., from an altitude of 10°, over zenith to W. ; dark 



space to SW. ; bay to W., persistent. 

 46. Centre of bay, 17° altitude, very bright above W 27° S. There seems no cloud in the dark space 

 at the bay, yet the stars seem dimmer in it than in the bright light of the aurora ; cirrous clouds 

 to N., formed of parallel linear cirri. 



50. Outline of auroral bay, like a reaping hook, the end of the handle in the horizon about W 30° S. ; 



the top of the handle, altitude 8° above W 44° S. ; the middle of the hook, 13° altitude above 

 W 26° S. ; and the top of the hook, 27° altitude above W 53° S. The light extends among 

 the clouds to N, and NE. up to the zenith. 



51. The auroral light extends to the south of the zenith, about 70° altitude above SSW., where it mixes 



with a light cloud, from which it can scarcely be distinguished ; aurora on SE. horizon, or cloud. ? 

 56. The clouds are moving off to E. The light to NE. springs from cloud, altitude 9° ; its eastern 

 extremity is at E 20° N. 

 8 0. Incipient streamers amidst light to NE. and to W by N. The light is retrograding towards N., and 

 has nearly attained the W. and NE. points of the horizon. 



2. Streamers more distinct to NE. 



3. A streak of aurora, unconnected with the horizon, has appeared suddenly to S. The streak is 



about 2° broad and 10° long, and the middle of it (both as regards length and breadth) is due 

 south, at an altitude of 12°. The streak disappeared in a minute or two. 

 I 6. Incipient arch springs from W., altitude of summit 26°. 



I 7- Light about equally luminous to NE. and WSW. ; slightly more concentrated at the former. As 



the clouds clear oiF, the greater part of the sky found covered with a milky aurora ; faint, equally 

 diffused light, excepting that here and there the light, more condensed, has the appearance of 

 arches ; the height of the well-defined aurora above the south is about 65° ; this is only an ap- 

 proximation, as the light thins off. 



11. The bay to WSW. is nearly obliterated. The southern portion of the light was at one time best 

 defined, but it is now like the rest. 



19. Altitude of «;eZZ-defined light from SSW., 65°. * ^ 



24. Altitude of well-defined light from SSW., 70°. 



27. The clouds have moved more eastwards ; sky covered to north, from 70° above SSW., with milky 

 aurora. 



36. The well-defined aurora now only reaches to the zenith. 



43. The altitude of well-defined aurora is now 85° above SSW, The northern semi-hemisphere is 

 covered with milky aurora as before. This milky appearance of the aurora is precisely of the 

 kind observed covering the sky, Feb. 1, 1845, &c. (See page 120.) 



58. The auroral light has drawn nearer to the north. 



59. Altitude of auroral segment above NNW., 57°. 

 8 0. Altitude of auroral segment above NNW., 48°. 



1. Altitude of auroral segment above NNW., 47°. 



5. It again became cloudy, but the aurora crept nearer and nearer the N. horizon. 

 8 9 15. Auroral arch to N. lO** b'^. Auroral arch to N. 



