Krug von Nidda on ilie Mineral Springs of Iceland. 103 



the Roaring Geyser, and which, at intervals of from four to five 

 minutes, projected its jets of water to a height of from thirty to 

 forty feet. 



Olafsen,* who visited the Geyser in the year 1804, observed 

 that the eruptions of the Great Geyser were repeated at inter- 

 vals of six hours, but that, besides these, smaller eruptions oc- 

 curred between, which, however, were of trilling intensity and 

 duration, whereas the greater lasted from five to ten minutes 

 rarely fifteen, and the jets of water were projected to a height 

 of 212 feet. He also witnessed an eruption of the Strokr, 

 which lasted uninterruptedly for two hours and ten minutes, 

 and by which the jets of water were thrown to a height of about 

 150 feet. 



Hooker saw the Geyser in 1809, and estimated the height of 

 the water at upwards of 100 feet. 



Mackenzie f visited the Geyser during his tour through Ice- 

 land in the summer of the year 1810. He enumerates many 

 eruptions, which, as it appears, were repeated at periods of from 

 two to three hours, and were sometimes very considerable, for 

 they continued several minutes, and the jets of water rose to a 

 height of thirty feet. He seems to have witnessed two of the 

 greater eruptions, so far as can be ascertained from his descrip- 

 tion, and the time that intervened between them was thirty 

 hours ; the highest jet attained an elevation of ninety feet. Du- 

 ring his stay in the country he also saw three eruptions of the 

 Strokr (the New Geyser), which occurred at periods of from 

 twelve to fourteen hours, and whose activity was continued un- 

 interruptedly from half an hour to three hours. 



In the year 1815, Henderson { visited the Geyser, and found 

 that its greater eruptions took place at intervals of six hours, 

 and the smaller at intervals of from one to one and a half hours. 

 During the great eruptions, the water-column rose to a height 

 of from seventy to eighty feet, and one jet to an elevation of 150 

 feet. The eruptions of the Strokr were repeated after periods 

 of tranquillity of twenty-four hours, and continued one hour. 

 Henderson caused an eruption by throwing stones into the pipe 



Gilbert's Annalen, vol. xliii. I Travels in Iceland. 



$ Journal of a Residence in Iceland. 



