As has been said, it was a natural grotto formed in the rocks, but apparently extending some distance into the range of hills which stretched nearly across the island. The rear portion narrowed down to what seemed to be a tunnel hardly more than four feet in diameter. In this Philip entered without hesitation, crawling upon his hands and knees for a distance of about a hundred feet, during which the passage grew more and more contracted, until to turn around would have been absolutely impossible.
At the end of such distance was an abrupt angle, after which it was possible for him to proceed in a half-bent attitude along the tunnel, which was floored with sand, and obstructed here and there by boulders or irregular blocks of what appeared to be limestone.
Perhaps he had walked in this second direction two hundred feet, when, on turning a second angle, he stood in an oval-shaped chamber about twenty yards wide, twice as long, and twenty-five feet high.
It was a marvelous scene which met his startled gaze. Those who have entered natural caves may have seen a similar picture, but certainly nothing more imposing.
In the center of this subterranean cavern was a small circular lake, hardly more than twelve feet in diameter, and sunken half a dozen inches from the level of a floor formed of blackish-gray sand, covered with small pebbles of various brilliant colors. The ceiling towered high above, and was dome-shaped, thickly-studded with pendant stalactites, as if Nature had thus given to the artisan the first idea of lincrusta work. On the right, or eastern side, were benches of rocks rising like terraces, bearing huge stalagmites shaped like animals, and incrusted with myriads of tiny crystals which glistened like diamonds in the light admitted through an opening partially obscured by the foliage in the center of the dome.
After standing silent and motionless several moments, lost in admiration of the scene before him, Philip pushed on toward another tunnel which led from the chamber directly opposite the one he had just traversed.
Here, after five minutes of leisurely walking, the air became warmer and humid, as if filled with steam, while on the left side of the tunnel was a stream of water from which arose a peculiar phosphorescent light which permitted the amazed traveler to see several inches below the surface.
A closer examination revealed the fact that the stream was filled with fish, shaped something like a trout, and, singular as it may seem, the luminous glow was emitted from their bodies. He plunged his hand in without alarming the finny tribe, and lifting one out discovered that it was blind, having no sign of an eye, which accounted for the readiness with which he had made the capture.
Curiosity impelled Philip to continue his explorations without delay, and he advanced rapidly along the tunnel, in which it was now possible to stand erect. With every step the air grew warmer, until it was as if one were suddenly plunged in a steam bath.