It seemed far away and burned with a pale yellow glare that would have seemed supernatural, had it been contemplated by any one of a superstitious turn.
As near as Mickey could estimate, they had gone over a hundred and fifty yards when the point was reached where the stream gathered itself and passed from view.

Its width was no greater than four feet, while its rapidity was correspondingly increased.
After Mickey had contemplated it awhile by the light of the torch, he handed the latter to Fred, and told him to go off so far that he would be left in total darkness.

This being done, the man set to work to study out the problem before him.
His theory was that, if the passage of the stream from the cavern to the outside world were brief, the evidence of it could be seen, perhaps, in the faintest tinge of light in the water, The sun was shining brightly on the outside, and unless the stream flowed quite a distance under ground, a portion of the refracted light would reach his eye.
Mickey peered at the base of the rock for a few minutes, and then exclaimed, with considerable excitement: "Be the powers! but it's there!" It was dim and faint, as light is sometimes seen through a translucent substance, but he saw it so plainly that there could be no error.

When he looked aloft at the impenetrable gloom, he was sensible of the same dim light upon the water.

He tested his accuracy of vision by looking in different directions, but the result was the same every time.
The almost invisible illumination being there, the Irishman wanted no philosopher to tell him that it was the sun striking the water as it reached the outside, and the outer world, which he was so desirous of re-entering, was close at hand.
Mickey was in high glee at the discovery, but when he regained his mental poise, he could not shut his eyes to the fact that if he attempted to reach the outer world by means of the stream, he ran a terrible risk of losing his life.