Close at hand are the Mammoth Paint Pots, in the center of the Firehole Geyser. We can explain the appearance of the Paint Pot or Mud Bath much more easily than we can account for the phenomenon. It is well named, because it resembles a succession of paint pots of enormous size more than anything else that the imagination can liken it to. The basin measures forty by sixty feet, with a mud boundary three or four feet high on three sides of it. The contents of the basin have kept scientists wondering for years. The substance is white, looking very much like ordinary paint, but, unlike paint, it is constantly in motion, and the agitation is so persistent that an idea is given that the Paint Pot's basin is the bed of a crater. The continual bubbling and vibration is very interesting in its effects, and the noise it makes is quite peculiar, not unlike a subdued hiss or a badly executed stage-whisper. Mixed among the white substance is a quantity of silicious clay of all sorts and conditions of color. This produces a variation in the appearance, but is merely in addition to what is otherwise marvelous in the extreme. Pearl gray, with terra cotta, red and green tints is the basic color of this boiling, seething mass, which seems to be continually at unrest and in a course of worry. The Excelsior Geyser is the most conspicuous feature of the Midway Basin, a collection of hot springs and pools. They are situated in the Midway Basin, and were originally called Cliff Caldron. Excelsior Geyser is in a continual state of anarchy, without law, government or regulation. It does just as it likes and when it likes. It seldom performs when wanted to, but when it does break out into a condition of fermentation, the effect is very magnificent. As one writer puts it, the beauties and exhibitions of this geyser are as far superior to those of all the others as the light of the sun seems to that of the moon. The geyser was for years regarded as the grandest spring in the park, before its exceptionally great features prevailed or became apparent. In the years 1881-82, the eruptions from this geyser became so terrific that it spouted water as high as 250 feet, and converted the generally inoffensive Firehole River into a torrent of storming water. Rocks of large size and heavy enough to be very dangerous were hurled headlong from within the mysterious confines of the earth, and were dashed around in all directions. For miles the terrific noise could be heard, and people who had been waiting for a phenomenon of this character, hurried across country to witness it. It is only now and again that a phenomenon of this kind is repeated, and the most skillful geologists are unable to give us any adequate forecasts as to when the next performance will take place.