740 THE AURORA BOREALIS. 



to be surrounded with a pale glimmer floating along the mountain, 

 and the spectroscope showed the existence in it of the yellow 

 light of the Aurora. 



The next day, September 26, a similar effect was seen in the 

 south-west, but the phenomena seemed to be much farther off than 

 on the day before. 



The next day (Sept. 27) a beam of yellowish- white light was 

 seen in the morning, and at 11.30 p.m. a faint glimmer was seen 

 gliding along the arete of the mountain, and, from the movement 

 of the mist, was evidently on the arete itself. The light appeared 

 for some seconds under the form of rays of a clear yellow of great 

 brilliancy, following the outline of the mountain. 



At other times all the tops and highest ridges of the mountains 

 were enveloped with a pale glimmer, generally when they were 

 covered with a thin veil of mist, the hght gradually dying out and 

 disappearing in the upper layers of the mist. 



On returning to Tromso, an Aurora was seen on October 21, 

 which commenced in the north and became very brilliant. 



The spectroscope showed — 

 (1.) A yellow line. 

 (2.) A very clear line in the blue. 



(3.) Two lines of a hair's breadth, with very pronounced 

 horizontal striae on the side of the yellow. 



The light of the yellow line was very variable in intensity. 



The relative places of the auroral lines were found to be — 

 (1.) The yellow line at 74-9. 

 (2.) The blue line at 65 ' 90. 



One of the shaded lines at 125 '0 and the other about 105*0. 



On the entrance of the " Sophie " into the Norwegian Archi- 

 pelago on the evening of October the 18th, fragments of polar 

 light were seen scattered here and there in all the sky to the north 

 and to the east, which finished by forming a continuous ring around 

 the horizon. 



Rays from this ring lengthened gradually and met together 

 suddenly about the zenith, forming during some instants a crown of 

 Aurora of perfect regularity, and presenting the brightest colours. 



(p. 157.) I have observed on several occasions discharges 

 accompanied the electric light arising from scattered clouds or 

 from beds of clouds. 



In these high latitudes it is not by the clouds only that electricity 

 is discharged ; it is also directly by the damp air, as also takes 

 place during winter in the temperate zone. We possess a great 

 number of direct observations verifying the existence of slow dis- 

 charges of this nature, and we have a remarkable proof of it in an 

 observation by M. Angstrom, who on one occasion has verified the 

 presence of the yellow line of the polar light nearly all over the 

 sky. If it is well established that the phenomena of the polar light 

 are due to the electricity of the air, it follows that its appearance 

 depends less on terrestrial magnetism than has been hitherto ad- 

 mitted. This may exercise a direct action upon the electric dis- 



