528 



SCIENCE. 



[Vol. V., No. 125. 



display of northern lights. A number of illus- 

 trations are given ; but in all cases they are 

 reproduced from drawings, as, even with the 

 most sensitive plates, he utterly failed in getting 

 any impression on a negative. He holds the 

 opinion that the fundamental phenomenon is a 

 ring of light encircling the earth, as shown in 

 fig. 2, and that all the various forms observed 

 are due to modifications and imperfections in 

 this ring. To the streamers he gives the posi- 

 tion which a dipping-needle would take, and 

 explains their apparent coming-together at the 

 magnetic zenith, as they do occasionally, as 



of 1883 to the Finnish polar station, Tromholt 

 takes occasion to criticise the artificial aurora 

 which Professor Lemstrom succeeded in get- 

 ting on the top of a hill. He thinks the light 

 more of the nature of St. Elmo's fire than a 

 true aurora. He also takes exception to Lem- 

 strom' s determinations of the height. 



Koutokaeino was the seat of a religious ex- 

 citement among the Lapps, which finally cul- 

 minated in 1852 in the murder pf the trader 

 and sheriff of the place, the pastor's life being 

 saved onty by the timely advent of a few 

 armed and sane Lapps from a neighboring vil- 



Fig. 3. — Tromholt's auroral station at Koutokaeino. 



due to perspective. He believes in such cases 

 that the observer is looking into a tube of raj's. 

 The geographical distribution of the aurora 

 is described, and the results of the various 

 estimates of the height given, Tromholt's own 

 measurements making the average height, of 

 the lower edge of a number of auroral arches 

 70.2 miles. The connection of the aurora with 

 the sun-spot periods is referred to, and a bi- 

 3'earfy variation in the phenomenon is made 

 probable. The crackling sound sometimes said 

 to have been heard, Tromholt was led to con- 

 sider imaginary. As regards the strength of 

 the light emitted, he sa}'s that at times he was 

 able to read print of the following size : — 



Aurora borealis. 



In the account of his journe} r in the spring 



lage. A somewhat similar excitement was in 

 1883 brewing at Hatta to the east of Kouto- 

 kaeino. 



The most of Tromholt's trips over the coun- 

 try were made in reindeer-sleds, when the snow 

 was hard, and were accomplished with few 

 more than the usual mishaps of such travelling, 

 although his St. Bernard dog, Rolf, did not 

 prove a congenial companion for the deer. 

 But the final journey, to Sodankyla, was made 

 when the sun had already begun to melt the 

 snow ; and, on his return, Tromholt pictures 

 himself as dragged through from one to two 

 feet of water for a great part of the way. In 

 the spring the land must resemble one vast 

 mud-puddle. Finally Tromholt returned to 

 civilization, and took his voyage along the north 

 coast of Scandinavia. 



Thanks to the cheap photo-engraving pro- 



