Now while the earl all unconsciously was sleeping, this little cavern of the sea was filling fast; for as the rising tide on the German Ocean met the downward current of the Forth, the water rose rapidly against the impending walls. Ashkirk knew not how long he slept, when he was suddenly awakened by an unusual sound, and, on attempting to rise, struck his head with violence against the stone roof of the cave, close up to which his boat had floated on the rising tide. His situation was fraught with danger and horror. Moored fast to a point of rock now far beyond his reach, the boat was wedged between the top of the cavern and the surface of the swollen water, leaving him thus imprisoned, coffined, as it were, in utter darkness, and with the deadly fear that the whole of this now submarine grot would be covered by the gurgling tide, in which case he would assuredly be drowned, "and die the death (as he thought) of a rat in a drain." The partial gleam of moonlight which had illuminated the mouth of this frightful trap had now passed away, and the darkness within and around it seemed palpable and opaque. He could no longer discern where the entrance lay, and his heart sank in the fear that the water had risen over it. He now heard the wavelets rippling, with a thousand hollow echoes, in the fissures and recesses, and gurgling with a sucking sound as they filled each in succession, and rose towards the gunwale of his boat, which had become perfectly immovable. And the tide was still rising! He found that he could not survive ten minutes longer. Already the air was stifling, and the necessity of making one desperate struggle for life became immediately apparent. Lying almost on his back, he groped breathlessly around him, and discovered a vacant shelf of rock upon his right. Clambering within it, he found with joy that it led to an inner and upper cavern. He had scarcely left the boat when, with a hoarse gurgle, the tide rushed in and filled it. As he ascended, a faint red light now flickered on the dark, stony walls of this slimy retreat; then, indeed, the heart of the gallant earl began to tremble, as his dread of supernatural beings returned. He remembered the strange figure which had disappeared so suddenly into the lower cavern when he first entered it. Again the terror of the water-kelpie came vividly upon him; for, in that time, all Scotsmen feared that evil denizen of their native seas and lakes.