A Summer's Outing, and The Old Man's Story

by Carter H. Harrison

On the following page is a cut showing a section of the earth crust, running across a valley and up the mountain side. Along its lowest point flows rapidly a stream of cold clear water fed by melting snows and dews on mountains towering above and more or less distant.

"G" is a geyser cone. Below is the geyser throat or well sinking down to "W".

"S" is a shaft more or less vertical opening into the geyser well and running far down into the softer rocks to "C" a somewhat horizontal continuation leading into "R" a recess or pocket in the softer upper rocks of sufficient capacity in some cases to hold hundreds or thousands of tons of water.

"P" is another recess opening into "R" near its apex. These recesses or pockets have been scooped out by superheated steam pouring up from far below through plutonic rocks contiguous to living central fires. Such steam is generated from veins and percolations of water always sinking from the earth's surface and from moisture believed to exist in or about all rocks.

"D" "D" and "D" are reservoirs on the surface of the earth or beneath it high up on the mountains, perennially supplied by rains and melting snows.

"V" "V" "V" are veins through which water flows from reservoirs "D" "D" "D" into recess "R" at "X". These veins are also fed by percolations throughout the formations through which they run. "F" "F" are fissures or seams in the upper rocks running into and extending deep down in the primative or igneous rocks below, along which highly heated steam generated near the internal fires underlying earth's solid crust, rushes upward into recess or pocket "P". We will assume that there are no veins conveying cold water into this latter recess or pocket.

Now we assume also that at a given moment recesses "R" and "P" and shaft "S" and its continuation "C" are free or nearly free of water. Steam, however, is rushing from them and out of geyser "G" in hot, roaring volume. In recess "R" it is encountering cold water flowing in at "X" and rapidly loses its high temperature and is being condensed. As such condensation goes on, the horizontal continuation "C" is being filled. As it fills the escape of steam at "G" lessens rapidly, until continuation "C" becoming full of water, it ceases entirely or only a small amount lifts lazily up from the hot shaft "S". The inflow at "X" and condensation fills recess "R" with water more or less cool. The steam coming up through "F", "F" no longer having an escape, heats the water in "R" until it reaches a line "L" in recess "R," where it becomes so hot as no longer to condense steam or does it to a very small extent. The pressure of the high heated steam now stops a further inflow at "X" and forces the water upward into shaft "S" and is capable of sustaining the column at the geyser throat "W" and the column in veins "V" at a like height. Condensation having ceased the steam in "R" above "L" and in "P" becomes superheated and acquires enormous expansive power. Finally its energy is so vast that a sudden expansion or explosion takes place. The water at "L" is pressed enormously downward and the contents of recess "R" are forced upward through shaft "S" into the geyser well and then through the contracted nozzle at "G" in a mighty jet high into the open air. The action of suddenly expanded or exploded steam is spasmodic and immediate. All of the water in recess "R" is therefore rapidly thrown out at "G". The water gone, fearfully hot steam follows it through "G" until its spasmodic energy ceases almost if not quite as suddenly as it was at first aroused. Immediately the steam, now coming from recess "R" begins to go through the cooling process before described, until again the shaft is closed at "C" and again a repetition of the eruption is brought about.

This series of actions is more or less regular in all geysers. In old "Faithful" the round is completed in about sixty-three minutes. The recesses or pockets are of various sizes in different geysers requiring different periods of time to be filled. The time taken to empty them, and in some measure the height of the jets depend probably very largely upon the size of the throat and of the nozzle of the geysers. "Old Faithful" has a comparatively small nozzle. His jet continues for several minutes and mounts to a great height. The same is true of the "Splendid." "The Castle" spurts up a very much larger volume of water; but not nearly so high, from a huge throat and in very much less time. The "Excelsior" has a throat many feet in diameter, and ejects a column proportionately large. Its actions are not regular and indeed it is rather a water volcano than a geyser, throwing up large stones and gravel.

"Young Faithful" emits no steam. It is probably only a sort of adjunct of some of the violently boiling pools near by. Steam, which in some of these cause violent turbulations at regular intervals, forces water through lateral shafts up through this little gem. Its throat is very small. A considerable body of water passing from behind with only a moderate force, yet finding only the small throat, makes a jet of considerable height. Jets resembling it are frequently seen on low rocky cliffs on the sea shore, caused by the ocean swell passing into grottoes and caverns and forcing water up along small fissures through the overhanging rock, called "puffing holes". The foregoing theory of geyser action may not bear the test of close criticism, but it is probable that such criticism may be answered by hypotheses not here alluded to. At all events it may be sufficiently satisfactory for the ordinary mind.