102 



SCIENCE. 



[Vol.. II., No. 25. 



In the Yellowstone national park, wherever 

 deep temperatures were taken in active springs 

 and geysers, thej' were found to increase with 

 the depth ; but temperatures of ebullition were 

 found at the surface of many springs, and in 

 some the temperatures exceeded the boiling- 

 point. As the time for an eruption in age3-ser 

 approached, the temperature increased, which 

 fact agrees with Bunsen's observations. 



In 1865 a Mr. Brvson of Edinburgh found 

 that the tube of the Great gej'ser of Iceland 

 has a ledge about forty-five feet below the top 

 of the tube, and that, from beneath this ledge, 

 steam-bubbles rose while the tube was filling. 

 A thermometer sunk to this point was violently 

 dashed about and broken, but, when sunk 

 below it, was quiet and undisturbed. The 

 conclusion is, that here is an opening b}' which 

 steam and superheated water have access to 

 the main gej'ser-tube from the side. Similar 

 side-openings are known to exist in Strokhr ; 

 but the Great geyser is so full of water that its 

 structure cannot be so readilv studied as in 

 the case of the smaller Strokhr. In Bunsen's 

 theory this point forty-five feet below the sur- 

 face pla3's an important part. He allowed his 

 thermometer to remain at the bottom of the 

 ge3-ser-tube during a great eruption, and it 

 was undisturbed. Mr. Bryson's discovery- 

 explains its safetj'. It was below the active 

 side-vent of the gej'ser. 



Bunsen's conclusion would therefore prob- 

 ablj' have to be modified so far as relates 

 to the temperature of ebullition not being 

 reached ; for, could he have obtained temper- 

 atures in the side-conduit, there is but little 

 doubt that the boiling-point would soon have 

 been reached, even' for the pressure of that 

 depth. The mass of water in the main tubes 

 prevents that condition at the surface; and, 

 when it is attained opposite the aperture, an 

 eruption occurs. 



Bunsen's theory of the formation of geyser- 

 tubes also requires some modification: Con- 

 trarj' to his opinion, the deposit of silica is 

 not necessary for geyseric action. In the 

 Gibbon ge3'ser basin in the national park are 

 several geysers conspicuous from the small 

 amount of siliceous deposit surrounding them ; 

 and one in '1878 was entirely without a deposit, 

 having just broken out as a steam-vent. By 

 the following year it had settled down to regu- 

 lar geyser action. 



As already mentioned, there are, in the park, 

 geysers the water of which is acid in reaction ; 

 and therefore the theory that before develop- 

 ing into a geyser the spring must pass through 

 a preliminary tranquil or non-eruptive stage 



(in which it is an acid spring) is not war- 

 ranted by the facts observed in the Yellow- 

 stone region. It is probable that all geysers 

 are originally due to a violent outbreak of 

 steam and water, and that the first stage is 

 that of a huge steam-vent. Under such con- 

 ditions, irregular cavities and passages are 

 more likely to be formed than regular tubes. 

 The lining of the passages and tubes takes 

 place afterwards, and is a slow process. 

 Whether the subterranean passages in which 

 the water is heated are narrow channels, en- 

 largements of tubes, or caverns and tubes, is 

 probably of little consequence, except as the 

 periods or intervals of the geyser are influenced. 

 If water in a glass tube be heated rapidly 

 'from the bottom, it will be violently expelled 

 from the tube, or, if boiled in a kettle that has 

 a lid and a spout, either the lid will be blown 

 off, or the water will be forced out of the 

 spout. In the first case we have an ' explana- 

 tion, in part at least, of Bunsen's theory ; and 

 the second exemplifies the theories which pre- 

 suppose the existence of subterranean cavi- 

 ties and connected tubes. The simpler the 

 form of the geyser-tube, the less is the im- 

 pediment to the circulation of the superheated 

 water ; and in this fact lies the explanation 

 of the difference between constantly boiling 

 springs and ge3-sers. The variations and 

 modifications of the subterranean water-pas- 

 sages, however, must be important factors 

 entering into anj' complete explanation of gej'- 

 seric action. 



Bunsen's theorj', somewhat modified, is 

 probably the best j-et proposed, especially that 

 part of it which explains the effect of the rise 

 of water nearly at the boiling-point to an 

 upper portion of the channel where its tem- 

 perature is in excess of that necessary- to cause 

 ebullition. The excess of heat is violentlj' 

 and instantaneously applied to the production 

 of steam. McKeuzie, in 1810, also recognized 

 the fact that the sudden evolution of steam 

 was the proximate cause of the eruptions ; but 

 he could not account for their periodical pro- 

 duction. 



The water of geysers and hot-springs has 

 been boiled and reboiled for an inconceivable 

 period, and is freed from air as no other water 

 is. Its cohesion is therefore immenselj' in- 

 creased ; and this fact, together with the 

 obstruction to the free escape of steam caused 

 bj- irregularities in the channels, offers a com- 

 plete explanation of the superheating of the 

 water ; and it is well known, that, when water 

 so heated does boil, the production of vapor 

 is instantaneous. A. C. Peale. 



