5 183 



norlh in the same ravine, we had intended to take samples of the gases from this 

 spring, but we had unfortunately to give up the idea, as on closer examination 

 it became evident that to collect the gas at that place would be an exceedingly 

 dangerous undertaking. 



To the north-west of the ravine mentioned, and separated from it by a high 

 ridge of gravel, are the three lakes shown on the map. The largest of these, which 

 is situated farthest west, covers the bottom of the wellknown crater Stora Viti, or 

 Helviti. The lake is enclosed on all sides by the steep edges of the crater. Towards 



Brei 6 1 t'i r 6 u T 



LANjO 



VestTnajuiav/ioT ■ -'(J" 



Fi^. 1. Icehiiid. 

 (Showing route and spring (Mstrict.s visited.) 



4^ 



the east, where the brink of the crater is highest, it reaches, according to a measure- 

 ment made by means of an aneroid barometer, the altitude of 55 m. above the level 

 of the water. To the west the edge only reaches the height of about 20 m., on 

 account of the declivity on which it stands. The two other lakes were, when we 

 visited the spot, formed into one single lake. This is most probably not because 

 a subversion has taken place, but is simjily the result of the surface of the two 

 lakes becoming higher, so that they communicate. Like Helvi'ti, these twin lakes 

 are surrounded by rather high banks sloping down to the surface of the water, 

 but unlike Helviti, the north-eastern and eastern slopes ai'e covered with active 

 solfataras. The photograph (Plate I, a) shows these twin lakes, from the south ; 



