224 Geysers of Iceland. 



especially at the moment of contact between the water and 

 the hot surface, easily accounts for the sounds heard, and 

 the force which causes the earth to tremble.* 



A glance at the above enumeration of facts, regarding the 

 manner of action of water placed in the circumstances men- 

 tioned, and which can be experimentally demonstrated, will 

 suffice to shew the applicability of those facts to account for 

 the cause of the phenomena exhibited by the Geysers. 



Two points, brought forward by different parties, remain 

 to be considered. The first is couched in the following 

 terms : — " Though it cannot be denied that these springs 

 have some communication with the volcanoes which abound 

 in the island, yet it is a remarkable fact that they are seldom 

 found very near them. ""J" The above quotation contains 

 information highly favourable to the spheroidal theory of 

 Geysers, for although the immediate presence of volcanoes 

 might supply us with the means of accounting for the fis- 

 sures being formed in the upper part of the cavity, yet, dur- 

 ing a volcanic eruption, the neighbouring land is generally so 

 much rent, that it would be almost impossible to suppose that 

 thebedof a Geyser could remain entirely unfissured, which is 

 so essential to the realisation of this theory. The second 

 point is, that " Henderson found that, by throwing a great 

 quantity of large stones into the pipe at Strockr, one of the 

 Geysers, he could bring on an eruption in a few minutes.'* % 

 This is a point of great importance, as it furnishes another 

 proof that the spheroidal theory of Geysers is the correct 

 one. For if we compel water to assume the spheroidal state, 

 by placing it in a heated vessel, and then drop into the 

 latter a small angular fragment of any solid substance, 

 we find that the water, which otherwise would have been 

 retained in the spheroidal condition, immediately wets the 

 surface of the vessel, and begins to be vaporised. 



* With regard to the phenomena which happens in the interval between 

 the eruptions, the reader is referred to the last paragraph of my memoir 

 inserted in the preceding number of this Journal, substituting the word 

 *• geyser " for " volcanic." 



t Ency. Brit. 7th ed. Article Iceland. Vol. xii. p. 146. 



I Lyell's Principles of Geology, 7th ed. p. 531. 



