INTRODUCTION. 9 



In spite of our barograph predictions of storms, our postman, a sturdy little Finmark man, now and 

 again happened to come in for dangerous weather when he came with the post from Kaafjord once or 

 twice a week. We were often afraid for him, but he was always alright, though sometimes so covered 

 with ice when he arrived, that he was quite unrecognisable. I once asked him if he were never frightened 

 when the weather was so bad. At first he did not answer, but sat quietly down to thaw; but a little 

 while after he said: "I'm too stupid to be frightened". 



Sad to say, our second aurora expedition was also destined not to terminate without a great mis- 

 fortune, which occurred just a week before we thought of packing up. 



The very road that our postman traversed every week as long as the expedition lasted, was to be 

 the scene of the death of two clever men, an avalanche having overwhelmed in Sivertdalen five persons 

 who were on their way to visit the observatory in Haldde on the i6th March. 



The two who perished were our good comrade, E. Boye, and Captain Lange, master of the Kaa- 

 fjord Mines' steamer; the other three escaped without injury. There had been an unusually heavy snow- 

 storm the night before, preceded by frost. 



THE EXPEDITION OF 1902-1903. 



3. The treatment of the observations that were collected during the 2nd aurora expedition, the results 

 of which have been published in the previously-mentioned work, showed with perfect clearness that in 

 order to solve the problem of the cause of the aurora and magnetic perturbations, it was necessary to 

 have at our command simultaneous magnetograms and observations from several suitable polar stations 

 at distances of about 1000 kilometres from one another, and also corresponding material from as many 

 other stations all over the world as it was possible to obtain. 



I demonstrated namely, that certain well-defined magnetic perturbations that occurred over large por- 

 tions of the earth might be naturally explained as the effect of electric currents, which, it might be sup- 

 posed, in the polar regions flowed approximately parallel with the surface of the earth at heights of several 

 hundred kilometres, and strengths of up to a million amperes, if they could be measured by their effect 

 as galvanic currents. These currents in the polar regions were well defined and greatly concentrated, and 

 often passed for the most part between two neighbouring stations, as, for instance, Bossekop and Jan Mayen 

 (see "Expedition", etc., 1. c., p. 27), in such a way that Bossekop lay quite on the one side of the current, 

 and Jan Mayen on the other; and the magnetic effect of the currents in the polar regions was not in- 

 frequently as much as 20 times stronger than in Central Europe. The investigation of these phenomena 

 would necessarily, of course, require simultaneous registrations of the magnetic elements at several uniformly 

 equipped polar stations. 



By such registrations, other important, unexplained phenomena that are very characteristically devel- 

 oped in the polar regions, might be excellently studied, e. g. the tremendous changes in the magnetic 

 components, which often occur at short intervals, especially during an aurora. A rapid registering of the 

 magnetic elements and of the earth-currents appearing simultaneously, would greatly assist the study of 

 these conditions. 



It was with these things in my mind that from the beginning of 1901 I began to work for the sen- 

 ding out of a new aurora expedition, with stations in Finmark, Iceland, Spitsbergen and Novaja Semlja, 

 so as to obtain observations simultaneously from both sides of the auroral zone. 



On this occasion also, the Norwegian Government looked upon my plans with favour, a grant of 

 20,000 krones being made by the Storthing towards a new expedition. The president of the Storthing, 



Birkeland, The Norwegian Aurora Polaris Expedition, 1902 1903. 



