634 THE UNIVERSE. 



Stephen del Bosco were twisted round upon their axis by 

 a circular impulsion, whilst their bases remained fixed. 

 M. A. Boscovitz, in his remarkable work on volcanoes, also 

 relates that during the convulsion of the island of Majorca, 

 in 1851, the shocks impressed a horizontal rotatory move- 

 ment on a tower, and that in the interval they lasted it 

 was displaced about 60 on its axis. 



We cannot terminate this rapid sketch of volcanic phe- 

 nomena without mentioning the singular geysers of Iceland, 

 which are essentially connected with them. They are hot 

 springs which, at certain times, issue from clefts in the 

 ground, and rise into the air in the form of a great jet of 

 boiling water. In the Great Geyser the watery eruption is 

 preceded by dull sounds like artillery, at the end of which 

 a jet of vapor and boiling water is launched into the air to 

 a height of a hundred feet. 1 



1 [The geysers of Iceland are small when compared with those of the Yellow- 

 stone Region in the Rocky Mountains. From its remarkable natural features a 

 portion of this region, 65 miles long by 55 broad, situated in the territories of 

 Wyoming and Montana, has been set apart as a national park. Over this tract 

 are scattered numerous hot springs and geysers, the most remarkable of the latter 

 being found in the valley of the Firehole River. Here there are upwards of 1500 

 hot springs and geysers, showing a great variety in their times of action, force, 

 mineral deposits, and color of water. The Grand Geyser, of which we give an 

 illustration, is the largest and most magnificent. It begins an eruption by filling 

 its basin with boiling water, forming a well 20 by 25 feet across, and having a 

 visible depth, when quiet, of 100 feet. The explosion is preceded by clouds of 

 steam rushing up to a height of 500 feet; the great unbroken body of water then 

 succeeds, ascending in one gigantic column to a height of 90 feet; while from 

 the apex of the column there rise five great jets, slightly radiating, which shoot 

 up to the unparalleled height of 250 feet from the ground. " The earth trembles 

 under the descending deluge from this vast fountain; a thousand hissing sounds 

 are heard in the air; rainbows encircle the summits of the jets with a halo of ce- 



