THE ICELAND GEYSERS.
Iceland is the birthplace of the word geyser. It has been called the land of frost and fire, and indeed in no place are the evidencesnay, the very forces themselvesof frost and fire brought so forcibly in contrast. The island is eminently a volcanic region, a central table-land with sharp volcanic peaks, hooded with great Jökuls, or glaciers, mantled with perpetual snows, and surrounded by a more or less narrow strip of low land bordering upon the sea. The evidences of internal fire are unmistakable. Hecla and other volcanoes are occasionally active, and the whole island is covered with lava poured out by the volcanoes, and the source of the heat supplying the geysers is unquestioned.
As would naturally be expected from the combination of water and fire, hot springs are abundant and at a few localities geysers are found. The most noteworthy of these is Haukadal, where The Geyser, Strokr, and a smaller geyser are found. This locality is about 70 miles from Reykiavik, the Iceland metropolis, and is only reached on horseback over beds of clinkers and rough lava fields; a dreary ride so far as scenery goes, but of fresh novelty to visitors from warmer lands. The hot springs are clustered in an area of about 20 acres, at the base of a hill about an eighth of a mile long and 300 feet high, and at the edge of the marshy bottom that stretches out toward the Hvita River. The springs are really at the base of the seaward border of the high ground, where the waters that have percolated through the tufas and porous lavas of the higher region would come to the surface. The two geysers Strokr and The Geyser issue from mounds of gray or white silica deposited by the hot waters, and the neighboring springs are surrounded by lesser areas of the same material, while on the hillside back of the springs the rock is decomposed by the steam of fumeroles. These two large spouters show two types of geysers. Strokr has a funnel-like pit 36 feet deep and 8 feet across (see page 25), expanding into a saucer-like basin. The tube is generally filled to within 6 feet of the top with clear water, which boils furiously, owing to the escape of great bubbles of steam coming from two openings in opposite sides of the tube. The eruptions are quite as beautiful as those of its more famous companion, the jets rising in a sheaf-like column to a height of 100 or more feet, eruptions taking place at very irregular and long intervals; but by putting a lid on this great kettle, by dumping in large pieces of turf, an eruption can be produced in a short time.
The Geyser, on the contrary, is a pool of limpid green water whose surface rises and falls in rhythmic pulsations. The usual temperature is but 170° F. or 200° F., but varies, being greater immediately before an eruption. The shallow saucer-like basin is about 60 feet across and slopes gently to a cylindrical shaft 10 feet in diameter, forming the pipe of the geyser; this is about 70 feet deep. This regularity of the tube becomes important when we consider Bunsen's experiments and the theory of geyser action he deduced from them. Before an eruption bubbles of steam entering the tube suddenly collapse with loud but muffled reports and a disturbance of the quiet surface of the water. During this simmering, for such it is, the water rises in dome-like mounds over the pipe and overflows the basin, running down the terraced slope and wetting the cauliflower-like forms of sinter that adorn it.
The eruptions that so long puzzled and astonished visitors to this remote land are surpassed by those of the giants of the Yellowstone, but their beauty is not less. A short time before Geyser plays, the domes of water rising in the center of the basin come in quick succession and finally burst into spray, followed by a rapid succession of jets increasing in height until the column is 100 feet high. Dense clouds of steam momentarily hide the glistening sheaf of jets, hiding it from sight, then drifting away in the breeze again reveal the sparkling shaft.
These eruptions have varied much in appearance and height since the geyser was first known. At present the column does not exceed 90 feet and the eruption lasts but a few moments. After it the basin is empty and seems to be lined with a smooth coating of white silica.
Last Updated: 02-Apr-2007