O'Hanlon pointed to the north-east, or shore side, of the Hole.
The two men drew nearer, and then, pausing a moment to fix their hats firmly on their heads and grasp one another round the waist, crept cautiously forward until they stood on the brink of the Hole. They looked down.
The Hole was almost square, about thirty feet by thirty feet, and narrowing irregularly as it went down to about half that size. The depth from where the two stood to the surface of the water below was thirty-five feet.
The bottom of the Hole was naturally scant of light, and the light now in the sky was poor and thin.
The sides were almost smooth, and at the bottom of the funnel the angles a little rounded in. The rock upon which they stood seemed to be about twenty-five feet thick, and the free space between the bottom of the rock and the surface of the water ten feet. Thus the height of the cave at the Hole was at the present time of tide--half-tide flood--ten feet.
At the bottom of the Hole the water was no longer smooth, even quiet, but broken and turbid, opaque, and mantled with froth. Every wave that entered the vestibule of the cave swung the uneasy seething mass inward, to return in a few seconds on the back-wash. But the froth did not come back every time; it crept further on, until at the third wave the froth disappeared inward, to be succeeded by other froth moving at the same rate.
It made one giddy to look for any length of time. After a few minutes both men drew back by mutual consent.
"No mortal man could live down there for five minutes," said O'Hanlon, with a shiver.
"No," said O'Brien, with a laugh, "or ghost either, for that matter. But, I say, O'Hanlon, what cool and roomy lodging it would afford to all the Fishery Commissioners in the United Kingdoms!"
"This is no place for joking," said O'Hanlon, uneasily. "Let us get back. I am sick of this place."