Page:The American Cyclopædia (1879) Volume VII.djvu/802

 736 GEYSERS United States commissioner of mining statistics, also visited and described the region in the same year. The geysers lie in two large groups, in what are called the upper and lower gey- ser basins. The lower basin, beginning near the junction of the East and Middle forks of the Madison, comprises an area of about 30 sq. m. The springs are divisible into three classes : 1, those which are constantly boiling; 2, those which are agitated only at particular periods; 3, those which are always tranquil. In the geysers proper the water is usually quiet until a short time before an eruption. Dr. Peale, who examined them in 1871, in connection with Prof. Hayden, divides the springs into seven principal groups. In the first group, at the N. end of the basin, the temperature of 67 springs, occupying a space of about a quarter of a mile wide by two miles long, was recorded. The lowest was 106 F., the highest 198. The temperature of the air was 50. Some of these are geysers, projecting the water from 2 to 5 ft., but most of them are simply silicious springs, a few being chalybeate. The second group, which lies 2 m. further S., nearer the centre of the basin, occupies an area of about The Thud Geyser. three fourths of a mile. Sixteen springs here ranged in temperature from 140 to 196. The temperature of the air was from 55 to 66. This group is composed principally of geysers, many of them throwing water from 5 to 10 ft. high. The principal one, on the slope of a hill, is about 20 ft. in diameter, with a rim 5 ft. wide and 5 ft. high. The column of water thrown from it is very wide, and reaches the height of 50 ft. Another is named the Thud geyser, from the dull suppressed sound given off as the water rises and recedes. It has a beau- tiful scalloped rim, with small basins around it. This group of geysers is said to resemble a factory village, the steam rising in jets from more than 100 orifices. The third group lies three fourths of a mile S. E. of the second, at the base of a spur of the mountains, and extending up a ravine about 1,000 yards. They cover a space 500 yards in width. The temperature of 20 springs ranged from 130 to 196. Near the centre of the group is a small lake, 600 ft. long by 150 wide, on the E. shore of which is a geyser spouting to the height of from 15 to 20 ft. There are three sulphur springs here, the only ones in the region, and S. E. of the lake is an iron spring. About 1,000 yards fur- ther S. is the fourth group, in a ravine about 1 m. long and 300 yards wide. It contains many springs and geysers, the temperature of 42 of which ranged from 112 to 198, the temperature of the air being about 60. The principal geyser is at the mouth of the ravine. Its basin is circular and about 60 ft. in diameter, and its spring, in the centre, from 15 to 20 ft. The water is blue, and is constantly agitated. When in eruption the column is projected 100 ft. high, and is accompanied by immense clouds of steam. Near the upper end of the ravine is a spring around which the deposit is black, instead of the usual white. The fifth group, on the banks of the Fire-Hole river, is the largest of all, covering nearly a square mile and comprising a great number of springs and geysers. The temperature of 95 examined ranged from 112 to 196, the air at the time being 70. None of them are of much im- portance. One, from its resemblance to a shell, is named the Conch spring ; its basin is trian- gular, from 8 to 10 ft. in diameter. A little be- low it, on the bank of the river, there is a fine geyser, with a crater 3 ft. high. The Horn geyser has a crater like a horn, about a foot in diameter at the top and 6 ft. at the base ; it is in constant ebullition. The Bath spring has a square basin 30 ft. across, of unknown depth. The Cavern has a basin 15 by 20 ft. wide and 20 ft. in depth ; the water is of a bright blue tint, and of wonderful clearness. The mud springs of this group are from an inch or two to 20 or 30 ft. in diameter, their contents varying from turbid water to stiff mud. They are in a constant state of agitation. The mud is of different colors, being pure white in some, in others brown, black, or blue. The sixth group is 2 m. S. W., on a small stream flowing into the Fire-Hole. They are in an open, prairie- like valley, for the most part marshy. The temperature of 34 of the springs varied from 106 to 198. One of them is strongly chalyb- eate. The seventh group is on the Fire-Hole river, about 2-J- m. S. of the preceding. The temperature of 20 of the springs ranged from 132 to 196, when the air was from 70 to 76. The largest has a basin over 400 ft. in diameter. Below it is another huge spring, named the Caldron, the view of which is al- most obscured by the dense clouds of steam rising from it. The upper geyser basin lies in the valley of the same river, about 8 m. S. of the lower basin. It is not so large as the latter, covering an area of only about 3 sq. m., and it contains fewer springs; but! the phenomena exhibited are far more remarkable. Most of the springs and geysers are near the river, ex- tending along on both banks about 3 m. The temperature of 106 of them ranged from 113 to 196, the average being over 170, the tem- perature of the air being 67. At the head of the valley, at its southern extremity, stands Old Faithful, a geyser so called for its rcgu-