94 Krug von Nidda on the Mineral Springs of Iceland. 



The hot-water springs of this valley always attract first the 

 attention of the traveller, for among them are the great Geyser 

 and the Strokr, whose gigantic eruptions present the most in- 

 comparable spectacle. 



The Geyser has heaped up a flat cone of siliceous tuffas and 

 sinters, having a height of 25 or 30 feet, and a diameter of 200 

 feet. At the summit there is an almost round basin, a/ whose 

 deepest point is the mouth of the funnel-shaped pipe of the 

 spring. The basin measures at its edge sixty feet in diameter, 

 and is six or seven feet in depth. The pipe of the spring has, at 

 its junction with the basin, a diameter of about ten feet, but at 

 the furthest point to which we can see, it contracts to about 

 seven or eight feet. It descends quite perpendicularly to a depth 

 of seventy feet. The side walls of the perpendicular passage con- 

 sist of siliceous incrustations. The internal surfaces of the ba- 

 sin and of the channel, which are in constant contact with the 

 water of the spring, become so smooth from the friction, that 

 they acquire a polished appearance. But on the exterior of the 

 cone we find the siliceous masses in beautiful crystalline groups, 

 and in bush-like forms, having often a striking resemblance to 

 cauliflower. As this exterior is moistened only from time to 

 time by the water thrown out during the eruptions, or which 

 falls in drops, the silica held in solution is, by the gradual eva- 

 poration of the water, placed in such circumstances as to admit 

 of the action of a crystalline power of attraction during its de- 

 position. 



Two hours had elapsed since the first small eruption, and not 

 the smallest activity was perceptible in the Geyser. The water 

 filled about half the basin, and was perfectly still. Thin clouds 

 of vapour only were formed on its surface. The thermometer, 

 when placed in the water, indicated 72 R. (194. F.), and the 

 temperature diminished as the evaporation proceeded. Sudden- 

 ly I heard a dull sound like thunder under my feet, and imme- 

 diately there followed five or six violent reports from beneath, 

 during which the earth trembled. The water of the geyser be- 

 gan to boil violently; the basin became filled to overflowing; 

 large bubbles of steam broke forth from the funnel-shaped pipe, 

 and threw the water, by several successive impulses, to a height 

 of about twenty feet. Stillness was restored in a short time. I 



