104 Krug von Nidda on the Mineral Springs of Iceland. 



of the Strokr, and, in that case, the water rose to an elevation 

 of 200 feet. 



Lastly, in the year 1834, John Barrow * visited the Geyser. 

 After thirty-five hours of fruitless expectation of one of the great 

 eruptions, and after being frequently deceived by the subterra- 

 nean noises which precede each of the numerous smaller erup- 

 tions, this traveller was at last rewarded by the surprising spec- 

 tacle of one of the great eruptions. He estimated the height of 

 the column of water at from seventy to eighty feet. 



The water of the Geyser, the Strokr, and the other neighbour- 

 ing springs, deposites, during evaporation, in the form of tuffas 

 and sinters, the silica which it contains in such considerable quan- 

 tity. Over a large tract in the vicinity of these springs the sur- 

 face consists of a thick crust of these deposits. The basins of 

 all the thermal springs, and the walls of their pipes, are formed 

 of them. The bodies which are moistened by the water of the 

 springs are speedily covered by the siliceous matter, and we find 

 stalks of grass, rushes, turf, leaves, and many other objects in- 

 cluded in the tuffa. 



Bergman submitted the incrustations of the Geyser to a su- 

 perficial analysis, and was the first to discover their siliceous na- 

 ture. We are indebted to Klaproth for a more exact analysis, 

 according to which the sinter consists of silica, with one and a 

 half per cent, alumina, and a half per cent, oxide of iron. 



Stanley filled several bottles with the water of the Great 

 Geyser, and of another hot spring near the church of Reikum 

 in Guldbringesyssel, which is precisely similar to that of the 

 Geyser, and sent them to the two chemists Black and Klaproth. 

 Both examined the water, and found that 10,000 parts of the 

 water of the Reikum-Huer contain, 



According to Klaproth ( 



Carbonate of soda, 1.04 



Sulphate of soda, 1-73 



Muriate of ?oda, . 2.93 



Silica, 3.10 



8.80 



A Visit to Iceland in the Summer of 1834. London, 1835. 



Klaproth's Beitrage zur chemischen Kenntniss der Mineral-Korper, 

 vol. ii p. 99. 



