He was not long in reaching it, and by noon had cut through five feet of the calcareous stone, piling up the portion cut away in a kind of wall on the lower side, where the rocky floor sloped somewhat precipitously, forming a channel, through which a considerable rivulet stole silently along, to join and lose itself in the great ocean that for miles and miles surrounded it on every hand.
For four whole days he worked like a Trojan, cutting away and piling up the soft, limy stone, and on the fifth was rewarded by a glimmer of sunlight shining through the aperture he had made in the landward part of the rock.
From the small opening he could see the tent, the tall palm trees that sheltered it from the fierce rays of the meridian sun and the tapering masts of the old schooner as she lay fast aground on the blistering strand, and the landwash lazily undulating against her stern.
A little way beyond, some gulls and a blue heron were watching for flying-fish, great numbers of which would every once in awhile skim like so many silver leaves over the surface of the water, coming up and going down at short intervals, more in fear than play, for no doubt their relentless enemies, the dolphins, were after them, with a view to making a meal off as many as were so unfortunate as to come within their reach.
Frank could not repress a shout of delight, in which there was mingled a good deal of pardonable triumph, when he nimbly scrambled through the narrow aperture he had made with so much patient toil, and stood on the firm, warm earth without the gray, damp cavern.
All about his feet grew luxuriant ferns, soft mosses and trailing vines, the vegetation gradually lessening as it met the base of the dark rock forming the roof of the cave, and disappearing altogether before it reached the summit, or what Frank judged would be the summit if one were to approach it from the direction of the tent.
The next three days Frank spent in removing the most perishable part of his goods to the cave, and this he did none too soon, for the afternoon of the third day a dense black cloud suddenly arose in the northwest, accompanied with ominous rumblings of thunder and quivering flashes of lightning.
There was no fresh water on the island, so far as he had been able to discover, and the patter of the big rain-drops on the broad leaves of the palms was not only a pleasant sound, but one that assured Frank that for a time, at least, he was not likely to die of thirst.
This warning foretaste of what he might expect for the next three months, if he stayed so long on the island, admonished Frank to make himself as comfortable as possible in the cave, and from its snug shelter defy wind and wave.
He had heard Dunham say that these sudden storms were diurnal in their nature, and frequently of great fury and destructiveness, so the following morning he moved all his belongings into the grotto, as he liked best