804 Rev. Mr Farquharson on the Appearance and 
number of times ; and have remarked a certain order in its ap^ 
pearance and progress, which it is the object of this paper to de- 
scribe. The subject acquires interest from its evident connec- 
tion with the new science of electro-magnetism. 
In this latitude (about 57° IS' N.), the aurora borealis, on 
those nights when it is visible, generally first shows itself after 
dark, like a bright but circumscribed twilight, on the visible 
horizon *, the centre of which is exactly on the northern point 
of the magnetic meridian. So long as the bright space con- 
tinues low, its light resembles nearly the pale blue-white light 
of the real twilight, but varies momentarily in intensity, by in- 
cessant and undefined fits of gleaming and obscuration. 
By degrees the meteor enlarges itself, rising higher, and- ex- 
tending more from east to west on the horizon. The play of 
the fitful gleaming light becomes gradually better defined, and 
the whole luminous space presents the appearance of pencils or 
bundles of rays, pointing upwards, and, when viewed in narrow 
compartments, maintaining a parallelism among themselves, simi- 
lar to that exhibited by the rays of the sun, when he shines 
through broken clouds, athwart a hazy atmosphere. The rays, 
which are on the magnetic meridian, are parallel to that line, 
pointing exactly to the zenith; and those which are consider- 
ably to the eastward or westward of that meridian, are directed 
to the zenith, or to a point which appears within the limits of 
10° to the southward of it. 
The bluish-white light changes intoa beautiful palegreen, which, 
when the meteor rises quite above the horizon, as will be afterwards 
described, becomes tipged at the lower extremity of the pencils 
of rays, with blue and violet, and at their upper extremity with 
yellow and orange. The rays are very various in their intensity 
of light, as compared with one another; their higher and lower 
portions also frequently differ from each other in that respect ; 
and the whole appearance of each ray varies incessantly. It now 
breaks of, and disappears for a considerable space at its higher or 
lower extremity, and then immediately becomes again luminous 
* The observations have been made in a valley, surrounded on all sides by 
hills from <500 to 1000 feet high, and from two to five miles distant from the place 
of observation. 
