Volcanos and Earthquakes, 53 



steam were formed at the surface, the temperature of the water 

 was 194}° F., which was reduced still lower by the evaporation. 

 After a dull rumbling noise within, the water suddenly began 

 to boil up again, the basin was filled till it flowed over, immense 

 bubbles x)f steam burst from the funnel-shaped opening, and 

 })rojected the water to a height of about twenty feet. Imme- 

 diately after the eruption, when tranquillity was completely 

 restored, the water was at the boiling point, but its tempera- 

 ture soon fell below that degree. 



The Strokr, the eruptions of which almost exceed in gran- 

 (leur those of the Great Geyser^ has this peculiarity, that it is 

 at the same time a permanent and an intermittent thermal 

 spring. It shews itself to be permanent by its incessant ebul- 

 lition, and intermittent by the tremendous eruptions which 

 seem to be repeated at intervals of from two to three days. 



No doubt can be entertained respecting the nature of the 

 .igent by which the waters of the Geyser^ tlie StroJcr, and other 

 less considerable springs, are thrown to such an immense 

 height. It is, as in volcanos, a gaseous body, principally 

 aqueous vapour. We may, therefore, very fairly agree with 

 Krug Von Nidda, and consider volcanos in the same light as 

 intermittent springs, with this diflerence only, that instead of 

 Mater they throw out melted matters. 



He takes it for granted that these hot springs derive their 

 temperature from aqueous vapours rising from below. When 

 these vapours are able to rise freely in a continued column, 

 the water at the different depths must have a constant tempera- 

 ture, equal to that at which water would boil under the pres- 

 sure existing at the respective depths. Hence the constant 

 ebullition of the permanent springs, and their boiling heat. If, 

 on the other hand, the vapours be prevented, by the compli- 

 cated windings of its channels, from rising to the surface ; if, 

 for example, they be arrested in caverns, the temperature in 

 the upper layers of water must necessarily sink, because a large 

 (juantity of it is lost by evaporation at the surface, which cannot 

 be replaced from below. And any circulation of the layers of 

 water at different temperatures, by reason of their unequal spe- 

 lific gravities, seems to be very much interrupted by the nar- 

 rowness and sinuosity of the passage. The intermitting springs 



