Fig. 36. Giant Geyser
From Dana's Manual of Geology
Fig. 37. Bee Hive
From Dana's Manual of Geology
That shown in [Fig. 36] represents the shape of the cone of the giant geyser in the upper geyser basin of the Fire-Hole, Yellowstone National Park. This cone is about ten feet in height, and twenty-four feet in diameter. As shown in the figure it is broken on one of its sides. It throws out, at long intervals, a column of water the height of which varies from ninety to 200 feet.
[Fig. 38] represents the crater of a cone known as the Bee Hive in eruption.
Besides the above named geyser regions there is another region on the shores of Celebes, and a small region on San Miguel, in the Azores Islands, in the Atlantic Ocean.
Besides hot springs and mud volcanoes there are two other phenomena connected with volcanic action that we will now briefly describe.
When eruptions take place and the lava begins to flow down the side of a mountain, the different vapors and gases with which the lava is charged begin to escape or pass out from the boiling or fused mass. When these substances are of such a character that they produce fumes, or the vapors of various chemical substances, that become solid on cooling, they form what are called fumaroles, a word derived from a Latin word meaning "to smoke." For the greater part, fumaroles are found on the edge of craters, but sometimes are found in cavernous places either in the crater or in the lava streams.
There is, still, another class of openings through which only sulphurous vapors escape. These are called solfataras, a word derived from the Italian word solfo, or sulphur. Solfataras are generally found in regions distant from volcanic action. In the materials that escape from recently ejected lava, or molten lava, the temperature is high enough to volatilize many of the solid ingredients. But where the temperature is low, only sulphur vapors are driven off. It is for this reason that fumaroles are only found around the craters of active volcanoes, or on the lines of cracks or crevices of the lava stream where the temperature is very high.