------------------------------------------------------------------------ [Illustration: CUPID’S CAVE, MAMMOTH HOT SPRINGS.] The most interesting, because always reliable, is Old Faithful Geyser, which throws up a stream of hot water six feet in diameter 130 feet high every fifty-seven minutes, and sustains the flow for a period of five minutes. The amount of water thus discharged every hour is 100,000 gallons, or enough to supply a small river. The Bee-hive, located on the opposite side of the river, blows up a column of water three feet in diameter to a height of 250 feet, and plays, generally, for fifteen minutes, but at intervals of twenty-four hours. The Giantess is, for several reasons, the most interesting of all the 700 geysers within National Park. One may approach to the very brink of her crater, which is twenty feet across, and look down one hundred feet into her hot throat and hear the fierce gurgling of water, but none is visible until an eruption is about to occur. Then the sputtering increases, deep groans are audible, and a burst of steam is followed by a discharge of water that shoots upward in a succession of jets. The first main column sent up reaches a height of sixty feet, through which there are projected small streams a foot in diameter to a height of 250 feet, thus making a magnificent display for twenty minutes which nothing artificial can ever rival. Giant Geyser is less pretentious than the Giantess, having a ragged cone that is broken on one side, and through a vent eight feet in diameter a discharge is made at irregular intervals, when a stream of water is tossed to a height varying from 90 to 200 feet, and the activity sometimes continues for two or three hours. Other geysers that make fine displays are the Sawmill, Turban, Grotto, Punch-Bowl, Soda, Grand, Fan, and Riverside, some of which are never quiet, while others play only occasionally. It has been found by experiment that foreign substances thrown into some of these craters create an agitation that frequently results in eruptions; the introduction of soap or lye is invariably attended by some manifestation even in the quiet geysers, while the active ones are by this means made to flow again almost immediately after an eruption has taken place. ------------------------------------------------------------------------ [Illustration: