THE AURORA BORE ALTS. 739 



M. Lemstrom concluded that an electric discharge, which could 

 only be seen by means of the spectroscope, was taking place on 

 the surface of the ground all round him, and that from a distance 

 it would appear as a faint display of Aurora. 



At the end of his very interesting paper on the spectrum of the 

 Aurora and on his Lapland Expedition, M. Lemstrom sums up 

 the results obtained by himself and other observers thus : — 



(L) The phenomena of pale and flaming light which is some- 

 times seen on the tops of Spitzbergen mountains appear also in 

 Lapland, and are of the nature of the Aurora. 



(2.) Phenomena of the same kind, although with some difier- 

 ences, have been observed in other countries, showing that electric 

 discharges of the nature of the Aurora take place in other than 

 Arctic regions. 



(3.) The spectroscope is the surest means of deciding the kind 

 of the phenomena in doubtful cases. 



(4.) In Polar regions the electric discharge of thunder lies 

 lower in the atmosphere than elsewhere. 



(o.) Earth currents which accompany the Aurora are not 

 induction currents produced by the Aurora, at least not in 

 northern regions. 



(6.) In all probability the current of polar light would act on a 

 galvanometer, provided the apparatus which collects the elec- 

 tricity is large enough, or placed high enough in the atmosphere. 



(7.) As a rule, positive electricity comes down from the upper 

 regions. 



(8.) The corona of the Aurora Borealis is not entirely a 

 phenomenon of perspective, but the rays have a true curvature. 

 (This is explained on the supposition that the rays are currents 

 flowing in the same direction, and therefore attract each other.) 



(9.) In the Aurora spectrum there are nine rays, which in all 

 probability agree with lines which belong to the gases of the 

 air. 



(10.) The Aurora spectrum can be referred to three distinct 

 types, which depend on the character of the discharge. 



20. Observations on the ELECTRrcAL State of the Air during 

 the First Swedish Expedition in 1868, by M. Lemstrom. 

 — (Archives Sciences Physiques, &c., tome 41, 1871.) 



Toward the end of September, at Southgat Strait, between 

 Danskow and Spitzbergen, lat. 79° 39' 7'' N., long. 1 1° 7' E., 

 between mountains 300 metres (1,000 feet) high (m the north 

 and south, the auroral light was seen on the outline of clouds on 

 the mountain, and about 10° or 15° above the mountain, in undu- 

 lating lines, presenting a diflused yellowish light at their base, 

 from which vertical orange bands shot up, forming a series of 

 very prominent sharp points at the top. The crest of the moun- 

 tain became enveloped in mist with the wind from the E.N.E. 

 For some minutes after the cloud had passed, the crest continued 



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