for the earth trembles, and the roar when the geyser is in action is that of an earthquake, while great stones are scattered about for several hundred feet. Close by it are the "Prismatic Springs" and the "Turquoise." The first is two or more hundred feet in diameter and is a placid mass of scalding water. It has various depths; in the center where very deep, it is of an indigo blue which shades off into a bluish green; then where very shallow, it runs off into yellow, orange, red and brown, while some circles are white. It is a marvel of beauty. The color of the Turquoise is precisely described by its name.

The whole park plateau is filled with hot springs, which are building up elevations with their deposit and mounting them as they build. The water is all clear as crystal, but holds in solution lime, iron, sulphur and other minerals, which it deposits sufficiently fast to encrust a key, horseshoe, or other piece of metal in three or four days with a solid enamel—say the sixteenth of an inch in thickness—and of the appearance of second-class white sugar.

The geysers eject, when in action, large quantities of water, but the springs, though boiling and spouting, and appearing to be lifting much water, flow over their rims in very small streams. As they flow they build up their margins, which are thus made almost exactly level. This gentle flow runs off in wavy ripples generally; not in little rivulets, but in thin sheets, depositing the solid matter they have held in solution while below, which is freed by the action of the atmosphere. In this way the springs lift themselves, and build lofty hills. The deposit when fresh is hard, but when dry becomes generally friable, though there are cases where it maintains great hardness. These deposits often times wear beautiful colors, and nearly always do so when being made or while under water. Some of the quiet pools are over 100 feet in diameter. The outer edges when shallow are of a deep brown, followed by a lighter brown or red, then blending into a yellow and followed by a yellow olive, and deepening as they sink into dark olive, while in the deep throats they are almost black. The water before it makes the deepest point, in some is of emerald greenness, in others of exquisite blue; along the steep sloping walls assuming a rich amethyst or tinted in exquisite sapphire.

All deposits take either a wavy or a tufted form, whether on gentle slopes or on perpendicular walls. Some steep walls are not unlike slightly tufted fleeces of wool. The tufts are of all sizes, from that of an orange up to others as large as a bushel basket. One can scarcely realize that these tufts are hard. They appear beneath the water to be as light and soft as newly fallen snow upon an evergreen bush. Some of them are creamy white, others yellow, orange and all shades of brown. In one of the Geyser basins is a large pool actually used by the hotel people as a laundry tub. If you will promise not to mention it I will confess two evidences on my part of weakness. I always shed tears at the theatres, and I washed some handkerchiefs in this boiling pool and they came out nicely white.

NATURE'S PAINT-POTS.

To many, the paint-pots at the "Lower Basin" are the most curious things seen in the park. Imagine somewhat rounded pits of all sizes from those a few inches in diameter to others of forty and even sixty feet across, filled with fine white mud or mortar, such as plasterers call putty, and used by them for hard finish. This is boiling and plopping (I coin this word) like mush in huge pots, or thick soap in mighty caldrons. In boiling, the big bubbles lazily lift several inches high, and more lazily burst with a muffled noise, and sputter dabs of thick paste several feet into the air. Falling upon the rim of the pool, these erect a wall—now smooth as a plastered wall—and then in rough grotesque finish. No mortar made up for a first-class plaster finish was ever tempered as is this natural paste. When dry and pulverized it is an almost impalpable powder. The paste is sometimes white, but more often is of a pale scotch gray. One large pool is half white or whitish grey, the other half of a delicate peach blow. In one pot the putty was a pretty pink salmon. Putting these three colors on a cardboard to dry, I found that much of the coloring disappeared after exposure to the atmosphere. At one basin between the Yellowstone canyon and the great Yellowstone Lake, the mortar is of dark mud, pure and simple, and is lifted many feet in the air, and falling, is sucked back into a monster throat with horrible gurgling sound. Go to a slaughter house to see a stuck pig breathing his last. Multiply his agonizing throes several hundred fold and a good idea can be had of the struggle of these hidden monsters. One of the mud geysers is said at times to be so violent in its action, that the earth trembles for a very considerable distance, when the monster is in full eruption. Curiously there will sometimes be found a pool of crystal pure water boiling or spouting not many feet away, and in one instance, close to a mud boiling pool is a large spring of pure cold water. One is tempted to wish to turn one of these into the mouth of the mud geyser to wash down its throat and ease its agony. Neither the mud nor the white mortar in these craters overflow, but bubble, sputter, and plop year after year. The particles are as impalpable as the fine ground paint upon an artist's easel.

All kinds of pools, geysers and paint-pots are heated more or less highly, all of them nearly up to, and some much above boiling point. The heating is not from the visible water being near to any fire or heated surface, but from super-heated steam, generated far below, being forced through the surface water. Sometimes only steam escapes through the surface orifices. These are called vents. The steam coming from some of these is so hot that the skin would be taken from the hand by a single instantaneous application. They seem to be a sort of safety valves from the great steam generators in the bowels of the earth. No wonder the Indian gives this country a clear berth, or that a good schoolmarm tourist constantly had on her lips Hades! Hades!! Hades!!! To be candid, I think she used the old fashioned word.

LETTER III.

MAMMOTH HOT SPRINGS. A WONDERFUL FORMATION. THE WHITE ELEPHANT. A THEORY ACCOUNTING FOR THE HOT SPRINGS AND GEYSERS. MUD GEYSERS. MARVELOUS COLORINGS OF SOME POOLS.

The tourist entering the National Park by way of Livingston through the Gardner Canyon, and rocky Gateway, at about sixty miles reaches the "Mammoth Hot Springs". Here he sees a surprising formation. Before him rises in terraces each from twenty to thirty feet high, a great white cataract looking mass, several hundred feet high, bulging out into the valley. The center projects with rounded contour far beyond the wings, which recede on either side, and to be seen must be skirted. The entire bent crest is not far from three miles in length. When first approached, it strikes the eye as a succession of water falls tumbling from terrace to terrace. To a second glance it appears a system of falls one above the other hardened into dirty ice. To one who has visited lofty snow clad mountains, an act of deliberation is required to prevent him believing that the terraces are a part of a glacier of more or less purity.

The crests of the different terraces are almost level—some of them apparently exactly so. They are built by water, and, water here levels as it builds, for if there be a depression it seeks it, and depositing the solid matter held in solution, levels it up with the rest. From the crest of the upper terrace runs back a plateau of silicious incrustation covering 300 to 400 acres. Scattered over this, are shallow pools of hot water of a bluish white tinge. About their shallow sides these pools have concentric, tinted borders, some a few inches wide, others of one or two feet. These are bent to conform to the irregular shape of the pools, one within