On the Aurora Borealis. 259 



which, height the atmosphere must possess but t^-qV of P ar ^ °f 

 the density of that at the earth's surface. More modern ob- 

 servers think it seldom rises above the region of the clouds, 

 while Parry, Wrangel, Struve, Fisher, Farquharson, and others, 

 ascribe to it a very inconsiderable height. 



Observations made in Aberdeenshire tend to prove that at 

 times it is not more than half a mile above the surface of the 

 earth. Parry, in January 1825, whilst watching the varia- 

 tions in the forms of an Aurora, saw a ray of light dart down 

 from it towards the earth, between himself and the land, which 

 was some 3000 yards from him, two other officers of the expe- 

 dition witnessing it at the same time. I believe I am correct 

 in stating that many Arctic observers believe the Aurora to 

 attain a very small elevation in high latitudes. Hood and 

 Richardson observed the same Aurora from different places ; 

 to the one it appeared in the zenith, forming a confused mass 

 of flashes and beams ; to the other, many miles distant, look- 

 ing in the same direction as the first observer, it presented the 

 aspect of a low illumined arch. Sir William Hooker informs 

 me that, while passing a night on the summit of Ben Nevis, he 

 distinctly saw the Aurora hang in the valley between a neigh- 

 bouring elevation and that upon which he stood ; also, that at 

 another time, during a fall of snow upon a mountain side, he 

 observed the particles to be distinctly luminous, the air giving 

 evidence at the same time of the presence of much free elec- 

 tricity. General Sabine tells me that he has seen the Aurora 

 low down, and passed through it, as one would walk through 

 a mist. On the nights of the 30th and 31st March, 1859, I 

 noticed the Aurora between myself and the land. The patches 

 of light could plainly be seen a few feet above the surface of 

 the water in Bellot Straits, the opposite land being about two 

 and a half miles distant ; and I am confident that had the land 

 been sufficiently high, many of the Auroras seen during the 

 winter above the water space in Bellot Straits would have been 

 seen suspended above the water or ice at a low elevation. 



I give an abstract of over two years' continuous observations 

 in the Arctic regions. More than half the number of Auroras 

 noticed were seen in the direction of an open water space, 

 where much evaporation was going on ; these Auroras begin- 

 ning to appear at various degrees above the horizon, over a 

 fog bank. Many were observed when minute spicules. of snow 

 were visible in the atmosphere, or when a mist gradually 

 filled the air, also when cirrous clouds were seen, even when 

 their presence could only be detected — on account of their 

 thinness — by the formation of a halo round the moon. Occa- 

 sionally, when daylight appeared, and the Aurora became 

 gradually invisible, in its place thin fleecy clouds were noticed. 



