“If you doubt it,” he replied, “go nearer and examine it.”

[Illustration:  ON “ITS FLINTY SIDES.”]

We did so.  I scrambled up its flinty sides, and found an opening in the summit three feet wide.  I touched the rock.  It was still warm, and yet no water was discernible.  No sound was audible within its depths.

[Illustration:  THE CASTLE GEYSER’S CONE.]

“If this be really a geyser,” I remarked, “it is no doubt a lifeless one like Liberty Cap.”

My comrade smiled, looked at his watch, then at his notebook, and finally replied:  “Wait half an hour and see.”

Accordingly, we lingered on the massive ledges of the Castle Geyser, and learned that it is the largest, probably the oldest, of all the active geyser cones within the Park.  Once its eruptions were no doubt stupendous; but now its power is waning.  The gradual closing up of its huge throat, and the increasing substitution of steam for water, prove that the monster has now entered on the final stage of its career; for here, as on the terraces, we are surrounded by specimens of life, decay, and death.  The young, the middle-aged, the old, the dead,—­they are all here!

The fiery agitation of the pool and the impulsive spurts of water are indicative of youth.  A steady, splendid outburst proves maturity.  The feebler action of the Castle shows the waning powers of old age.  Last of all comes the closed cone, like a sealed sarcophagus, and that is death.

[Illustration:  THE CASTLE AND THE BEEHIVE IN ACTION.]

Meantime, the thirty minutes of expectancy had passed; and, suddenly, with a tremendous rush of steam, the Castle proved that its resources were by no means exhausted.  At the same instant, half a mile away, the Beehive Geyser threw into the air a shaft of dazzling spray fully two hundred feet in height.  I realized then, as never before, the noble action of our Government in giving this incomparable region to the people.  If this had not been done, the selfishness and greed of man would have made a tour here almost unbearable.  A fence would, doubtless, have been built around every geyser, and fees would have been charged to witness each wonderful phenomenon; whereas, to-day, thanks to the generosity of Congress, the Park itself, and everything that it contains, are absolutely free to all, rich and poor, native and foreigner,—­forever consecrated to the education and delight of man.

[Illustration:  THE CRATER OF OLD FAITHFUL.]

But no enumeration of the geysers would be complete without a mention of the special favorite of tourists, Old Faithful.  The opening through which this miracle of Nature springs is at the summit of a beautifully ornamented mound, which is itself a page in Nature’s wonder-book.  The lines upon its wrinkled face tell of a past whose secrets still remain a mystery.  It hints of an antiquity so vast that one contemplates it with bated breath; for this entire slope has been