496 THE POPULAR SCIENCE MONTHLY. 



left out, and yet the comparatively unimportant geyser area of tlie 

 Azores can perhaps be considered the African representative, while in 

 the boiling lake of Dominica, and the water-volcano of Guatemala, 

 Central and South America may be said to have geysers on a grand 

 scale. 



The difference between geysers and ordinary hot springs is not 

 readily explained, nor always recognized, although the difference 

 between a quiet hot spring and a geyser in active eruption is very 

 marked. However, these are the extremes, and between the two 

 there is every grade of action. Some geysers at times appear as quiet 

 springs, and others are constantly in active ebullition. A geyser may 

 be defined to be a periodically eruptive or intermittent 7io^. spring, from 

 which the water is projected into the air in a fountain-like column. 

 The word hot in this definition is italicized because springs containing 

 a large amount of gas may simulate geysers, as in the case of the Kane 

 geyser-well in Pennsylvania, which spouts regularly, and the artesian 

 well at Rank Herkany, in Hungary, which is fourteen hundred and 

 fifty-seven feet deep, and spouts at regular intervals to the height of 

 one hundred feet. Nordenskiold discovered an intermittent cold 

 geyser-like spring spouting through the ice-field of Greenland about 

 thirty miles from the coast. Almost all the constantly boiling springs 

 have periods of increased activity, and those which spout only a few feet 

 into the air have been classed as pseudo geysers. There are several 

 localities of the latter in the United States, particularly in California, 

 and Nevada. The geysers of California belong to this class, as do 

 also the mud- volcanoes of Southern California, although some of the 

 latter throw columns of water to the height of twenty feet, and are true 

 geysers. Besides the Yellowstone National Park, the Haukadal area in 

 Iceland, and the Taupo region of New Zealand, which are the geyser- 

 regions jt^ar excellence of the world, there are a number of places where 

 a few individual geysers are known, besides the Thibet area and that 

 of the Azores. In Mexico, at Aguas Calientes, near San Luis Potosi, 

 there is a geyser which spouts to the height of ten or twelve feet. 

 The Volcan de Agua, or water-volcano, of Guatemala, and the boiling 

 lake of Dominica have already been referred to. The latter has been 

 known since 1777. It is a seething caldron of unknown depth, meas- 

 uring two hundred by more than one hundred yards, situated in the 

 Grand Soufriere of Dominica, at an elevation of twenty-four hundred 

 feet above sea-level. It is sometimes quiet, with a temperature of 

 96° Fahr., and at others is in active ebullition, with a temperature above 

 the boiling-point, the water being thrown in jets into the air with a 

 noise like the discharge of artillery. At Atami, in Japan, there are 

 intermittent springs which spout about six times daily, although not 

 with any exact regularity. An immense volume of steam and slightly 

 sulphureted water is ejected. Geysers are found in Batachian, one 

 of the Moluccas, and at Nolok on Celebes there is a bowl-shaped spring 



