Krug von Nidda on the Mineral Springs of Iceland. 95 



immediately examined the temperature of the water, and found 

 that it had risen to the boiling point, but that immediately after- 

 wards it sank perceptibly. 



I had frequent opportunities of observing these small out- 

 breaks of the Geyser, as they were repeated in a surprising man- 

 ner, at regular intervals of two hours. The subterranean noise 

 which preceded them, and the concussions of the earth, roused 

 me several times during the night. On every occasion I has- 

 tened from my tent, and always saw phenomena similar to those 

 I have described. The same was the case on the following day. 

 In the evening, at half-past six o'clock, the roaring noise re- 

 sounded from beneath, and I proceeded to the edge of the basin. 

 Twelve to fifteen formidable thundering reports followed, du- 

 ring which the ground was violently agitated by a vibrating 

 movement. I hastened from the edge of the basin, for it threat- 

 ened to burst asunder under my feet. When I had reached 

 some distance, I stood still and looked back towards the Geyser, 

 when I witnessed that magnificent spectacle which can be pro- 

 duced only by the gigantic powers of subterranean agency. A 

 thick pillar of vapour rose to the clouds with the rapidity of an 

 arrow, and included in its interior a column of water which rose 

 with a wavering movement from the mouth of the Geyser to a 

 height of eighty or ninety feet in the air, but which soon fell to 

 half the altitude. Detached smaller jets ascended much higher, 

 and others were projected in inclined arcs from the envelope of 

 vapour. Soon the vapoury clouds were dispersed, and dis- 

 played the column of water, which, separated into innumerable 

 jets, was projected in a straight line upwards, then spread itself 

 out at its summit like a pine tree, and afterwards descended in 

 the form of a fine dust-like rain. The clouds of vapour speedily 

 collected round their nucleus, in order to exhibit it anew in a 

 still more surprising form. Several times the gigantic power 

 seemed worn out, and the column suddenly disappeared ; but 

 the earth was anew agitated dull thunder rolled beneath, and 

 the column of water was elevated into the air by the steam with 

 renewed force. The activity of the spring lasted, including the 

 short periods of repose, about ten minutes. The column of water 

 then sunk back into the mouth of the geyser, and stillness was 

 restored. I approached the basin, and found that the water 



