92 



during three expeditions to finnish Lapland: 1870 — 71, 1882 

 — 83 and 1883 — 84 and observed luminous phenomena under 

 raany different formes: 



a) Feeble fiames visible for the naked eye. 



b) Feeble fiames, shoived by the characteristic yellow 

 ray (y. r.). 



c) Aurora borealis, not visible for the naked eye but 

 proved by the same yelloiv raye in all directions. 



d) Luminous phenomena, natur al and artificial, above 

 the point-apparatus a) in the shape of feeble fiames; b) in 

 the shape of high beams. 



The both first kind of luminous phenomena has gene- 

 rally been observed around mountain tops and hills, but can 

 even be seen as luminous fogs in forests. It happens often 

 that they appear as a feeble yellow or reddish light widely 

 spread över the country, probably över several hundred 

 square miles, which is a good help when travelling during 

 dark nights in the winter. Their auroral character is pro- 

 ved by the characteristic yellow ray. 



Such a feeble light appeared especially during a jour- 

 ney from Sodankylä to Kultala 22—24 December 1882. It 

 w T as then observed during several hours and as the objects 

 in this light did not throw a shadow in any direction, it is 

 clear that we were in the light itself. We had no spectro- 

 scope at hand this time, but in analogy with what had 

 happened on other occasions, it would have no doubt given 

 the y. r. and it follows that we were surrounded by a feeble 

 auroral discharge. 



Though the feeble fiames and the more dispersed light 

 gave nearly always the y. r. it happened however in some 

 cases, that the y. r. did not appear, though we had all 

 reason to suppose the observed light to be of auroral origin. 

 When feeble fiames were analysed the eye had to be kept 

 from all other light, during several minutes, to possess the 

 necessary sensitiveness to observe the feeble y. r. in these 

 cases. 



