We climbed up on the white mound of the Giantess and waited hours for her eruption, for there was every indication of it, one sign being a thumping sound beneath our feet, but she failed to make a display till two hours after I had departed next day. This Geyser is a pool of water fifteen feet in diameter, so clear that one can see down into it thirty or forty feet, and so hot it boiled occasionally while we were lying around on the warm rocks waiting. When it did go off, I was told, it looked like a boiling pyramid, sending jets of water into the air 150 feet. When it subsides, which is not for a day or two, it leaves the crater empty to some depth; when it gradually fills up again, and in a week or two, just as it happens, off it goes again. That night the boys sat around the camp-fire, sung, and told stories, but with my thin clothes on I was glad to crawl just inside the tent, cover myself with blankets, and lie there watching the rest, and thinking of the wonderful experience I was having. The next morning I started back for Fire Hole, riding with the broken machine as well as I could, and saw the Grotto in eruption. This one is a mound six or eight feet high, filled with large holes through which the water spurts in all directions. And the Growler was muttering, too. This is not much more than a hole in the earth, but the deep, guttural sound that comes forth every few minutes with a gush of hot steam, leaves the impression that it is well named. I might go on and describe the Castle, the Grand, the Giant, and others,--there are seventy-one of these spouting hot springs in the park--but will mention only one more, and that the greatest of all. It is the Excelsior at Hell's Half Acre, an appropriate name, as you will see. It isn't a half acre alone, but an acre and a quarter of water heated to the verge of boiling. The immense caldron is so obscured by clouds of steam that one only obtains momentary glimpses of its surface, but he who has seen it may well speak of it as an outflow from the infernal regions. There is no sight in the park more impressive. The water, boiling sometimes, is about four feet below the banks that enclose it on one side, on which it is continually making encroachments. These banks jut over it from having been hollowed away beneath, and there is danger in going too near, as it is not easy to tell when they will cave in. The whole surface about is made by a lime deposit, and behind as well as before the visitor are these lakes of heated water, from which arise clouds of steam that are colored green and red by the reflection from the water below. This geyser has been known to go off but once, and that in 1882, when it suddenly burst forth, sending a stream of hot water 300 feet into the air, and boiling over such a quantity that it raised Fire Hole River two feet. It played for nearly a week, then subsided, and has since remained comparatively quiet. I wet my feet in the warm water, then started on toward Fire Hole.