Prof.  Comstock is quoted as thinking “Bunsen’s theory has not yet been proved adequate to explain the more prominent features of geyser eruptions.  Nor does it, in his opinion, account for all the differences between geysers and hot springs, and he proposes a structural hypothesis which combines Bischof’s and Bunsen’s theories.”

This hypothesis is illustrated by a figure in which a reservoir partly filled with water is connected with the surface by a tube having a double curve, and he explains that the water collecting in the depressed curve should confine the steam, rising from the reservoir in the other curve until the pressure is sufficient to cause an eruption.  His theory of action being that the water in the reservoir remains in equilibrium at a certain level, and the constant heat fills the space above with vapor, which heats the water held in the downward bend of the tube, and that also evolves vapor which fills the balance of the tube to the vent.  When the combined pressure of this vapor and water are overcome by the expansion of vapor accumulated above the reservoir, they are forced out, and followed by a portion of the water of the reservoir.  This theory is in the report of Captain Jones on Northwestern Wyoming.

The last theory cited by Dr. Peal is that of S. Baring-Gould, “Who visited the Iceland geysers in 1863, and thinks that a bent tube is sufficient to explain the action of the Great Geyser.  He took an iron tube and bent it in an angle of 110 deg., keeping one arm half the length of the other.  He filled the tube with water and placed the short arm in the fire.  For a moment the surface of the liquid remained quiet, and then the pipe began to quiver; a slight overflow took place, without any sign of ebullition, and then suddenly, with a throb, the whole column was forced high into the air.  With a tube, the long arm of which measured two feet and the bore of which was three-eighths of an inch, he sent a jet to the height of eighteen feet.  Steam is generated in the short arm and presses down the water, causing an overflow until the steam bubble turns the angle, when it forces out the column in the long arm with incredible violence.”

Dr. Peal now goes on to say: 

“Of the theories that we have just enumerated, perhaps no one is adequate to explain all the phenomena of geyser action.  Bunsen’s theory comes nearest to it, and in the simplest kinds of geysers is a sufficient explanation.  The variations and modifications in the geyser tubes and subterranean water passages must undoubtedly be important factors entering into any complete explanation of geyser action.  Now, of course, we can see what the conditions are at the surface, but in our experiments we can penetrate to a very inconsiderable distance.  We have, therefore, no data to present on these points, and investigations of this branch of the subject will have to be carried on in an artificial manner; that is artificial geysers