THE AUROEA BOREALIS. 723 



latitude of 60°, then on to the coast of Labrador and to the south 

 of Cape Farewell, then bending sharper to the northward it passes 

 between Iceland and the Faroe Isles near to the North Cape, and 

 on to the Northern Ice-sea to Nova Sembla and Cape Tschelyuskin, 

 and on just to the north of the Siberian coast to the south of 

 Kellett Land and Point Barrow. The grouping of the magnetic 

 meridians is very well shown in the map which accompanies the 

 paper. 



13. On a Definite Arrangement and Order of the Appearance 

 and Progress of the Aurora Borealis, and on its Height 

 above the Surface of the Earth, by Rev. James Farqu- 

 harson.— (Phil. Trans. 1829.) 



The following results had been arrived at from the observation 

 of a great number of Auroras in Aberdeenshire (lat. 57° 15' N.) 

 in 1823, and were communicated to the Philosophical Magazine : — 

 ^' That the Aurora Borealis has in all cases a determinate arrange- 

 " ment and figure, and follows an invariable order in its appear - 

 ** ance and progress; that the streamers (pencils of rays) of the 

 *' Aurora generally appear first in the north, forming an arch from 

 ^' east to west, having its vertex at the line of the magnetic meri- 

 " dian ; that when this arch is yet only of low elevation it is of 

 " considerable breadth from north to south, having the streamers 

 ^' of which it is composed placed crosswise in relation to its 

 ** own line, and all directed towards a point a little south of the 

 " zenith ; that the arch moves forward towards the south, con- 

 " tracting its lateral dimensions as it approaches the zenith, 

 " and increasing in intensity of light by the shortening of the 

 " streamers near the magnetic meridian, and the gradual shifting 

 " of the angles which the streamers near the east and west ex- 

 ^< tremities of the arch make with its own line, till at length these 

 *' streamers become parallel to that line, and then the arch is seen 

 " as a narrow belt 3° or 4° only in breadth, stretching across the 

 " zenith at right angles to the magnetic meridian ; that it still 

 " makes progress southwards ; and after it has reached several 

 " degrees south of the zenith again enlarges in breadth, by ex- 

 " hibiting an order of appearances the reverse of that which had 

 " attended its progress towards the zenith from the north ; and 

 " that the only conditions that can explain and reconcile these 

 " appearances are, that the pencils of rays (streamers) of the Aurora 

 " Borealis are vertical, or nearly so, and form a deep fringe, which 

 " stretches a great way from east to west at right angles to the 

 ^' magnetic meridian, but which is of no great thickness from 

 " north to south, and that the fringe moves southward, preserving 

 " its direction at right angles to the magnetic meridian." 



A remarkable Aurora was seen on Nov. 22, 1825. 



When first seen it had already formed two distinct and separate 

 arches in the north and north-eastern parts of the heavens ; the 

 continuity of each was only interrupted by a few detached masses 

 of low clouds coming, with a gentle breeze, slowly from the north, 

 and brightly illuminated by the moon. 



z z 2 



