TEMPERATURE OE THE HYDROSPHERE 201 



form of hot springs either represent the meteoric waters, which, as 

 ground water, descended to siifificient depth to be heated to a high 

 temperature, or which by contact with unexposed igneous masses 

 became heated ; or it is juvenile or magmatic water newly formed 

 and liberated from the molten rock. The temperatures of the hot 

 springs and geysers of Yellowstone National Park and of Iceland 

 have been regarded as due to the contact with igneous masses, 

 though Suess holds that they are due to the gaseous emanations of 

 lava masses lying at moderate depths below the surface, cooling to 

 a certain degree reducing them to the liquid state. Surface or 

 vadose waters may find access to these newly formed or juvenile 

 (magmatic) waters and so form a mixed product. 



In non-volcanic countries the water probably comes from great 

 depths. This is believed to be the case with the Bakewell Buxton, 

 warm springs of England, which range in temperature from 60° to 

 82° F., and the three hot springs of Bath, which have a temperature 

 varying from 104° to 120°, and yield an estimated quantity of about 

 half a million gallons daily. Prestwich estimates that the water 

 rises from a depth of about 3.500 feet. The Mountain Home hot 

 springs of Idaho have temperatures ranging from 103° to 167° F., 

 and Russell estimates that the depth at which this temperature would 

 be found in that region is about 5.000 feet below the surface. The 

 Hot Springs of Arkansas have a temperature ranging from 95° 

 upward, and, if not magmatic, probably owe their temperature to 

 contact with young igneous rocks still hot. 



In the Yellowstone Park there are more than 3,000 hot springs 

 and about 100 geysers. The geysers are intermittently eruptive hot 

 springs, throwing their waters into the air at intervals, sometimes to 

 a height of 200 feet or more. The eruption is believed, by those who 

 hold to the vadose origin of the waters, to be due to the superheat- 

 ing of a long column of water in a tube with hot walls. If this 

 results in the formation of steam in the lower part of the tube this 

 may lift the column, causing an overflow of the water at the top 

 and a corresponding relief of pressure. This permits a sudden 

 expansion of the superheated waters into steam on the relief of 

 pressure, and a consequent eruption of the entire mass. In the 

 change of the water to steam it expands about 1,700 times. (See 

 Hague-ii.) (Eig. 31.) 



Magmatic or Juvenile Waters. The steam clouds accom- 

 panying volcanic eruptions, and formerly regarded as due to infiltra- 

 tion of surface or vadose waters into the volcanic regions, are now 

 held by many geologists to be the result of gaseous emanations from 

 the lava itself and their cooling and condensation into steam and 



