(2) At no point does the water in the tube attain the temperature of ebullition which it should have under the pressure to which it is subjected, but the temperature depends on the time that has elapsed since the last eruption. As a great eruption comes near it approaches the boiling point. (3) At the depth of about forty-five feet the difference between the temperature of the water and the calculated boiling point for that pressure is the least. The main point of his theory appears to be that an eruption takes place when the water in the tube reaches the boiling point, and to account for it, "He supposes that the column in the central tube communicates by a long and sinuous channel with some space, be it what it may, which is subjected to the action of the direct source of subterranean heat. The temperature gets raised above the boiling point, due to the pressure, and a sudden generation of steam is the result. This steam rises in the column of water, which, being cooler, causes it to condense. Gradually the heat of the water is raised until the water of the channel must boil, and the steam therefore cannot condense, but must accumulate and acquire a gradually increasing tension. The condensation of the bubbles possesses a periodic character, and to this is due the uplifting of the water in what Bunsen calls conical water hills, which are accompanied by the subterranean explosions." 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.