PROCEEDINGS OF THE COTTESWOLD CLUB 277 



weir, which the forces of Nature seem powerless to attack, 

 and which will keep the Falls in their present condition 

 for centuries to come. 



I do not propose to give an account of all the ohjects of 

 scientific interest in this wonderful region. 1 went there 

 for the specific purpose of seeing and examining what, so 

 far as I know, are not to be seen on such a scale anywhere 

 else in the world, viz., the Geysirs ; and I shall conclude 

 my description with an endeavour to explain the causes of 

 the very peculiar phenomena presented by these natural 

 "water-rises" (which is surely as good an English word as 

 "water-falls.") 



A " Geysir" (the word is Icelandic and means a "gush- 

 ing torrent") differs from other natural springs in the 

 following respects : — 



I. — The water issuing from it is nearly or quite at the 

 boiling point, viz., 100° C., for the ordinary atmospheric 

 pressure. 



2. — The water is ejected with a force comparable to 

 that which is developed in the explosion of a high 

 pressure steam boiler. 



3. — The water is ejected, in nearly all cases, at very 

 irregular intervals, alternating with periods of complete 

 repose. 



The high temperature of the water is unquestionably 

 due to the same cause as that of a volcano, viz. : the near 

 approach to the earth's surfiice of some of the intensely 

 hot materials of which the interior is composed. Hot 

 springs are always, whether in Iceland, or in Auvergne, 

 or in New Zealand, or in the Rocky Mountains, an 

 accompaniment of volcanic action, and usually an indica- 

 tion of its decay. 



The cause of the violence and the intermittent character 

 of the eruptions of a geysir is readily understood by a 

 consideration of one or two of the elementary laws of 

 heat. 



S 



