The four castaways had been asleep for a couple of hours, that is, from the time that, following the example of the young Scotchman, they had stretched themselves along the bottom of the ravine. It was not quite an hour, however, since the commencement of the sandstorm; and yet, in this short time, the arenaceous dust had accumulated to the thickness of several inches upon their bodies; and a person passing the spot, or even stepping right over them, could not have told that four human beings were buried beneath; that is, upon the supposition that they would have lain still, and not got startled from their slumbers by the foot thus treading upon them. Perhaps it was a fortunate circumstance for them, that by such a contingency they might be awakened; and that by such they were awakened. Otherwise their sleep might have been protracted into that still deeper sleep from which there is no awaking. All four had begun to feel, if any sensation while asleep can be so called, a sense of suffocation, accompanied by a heaviness of the limbs and torpidity in the joints; as if some, immense weight was pressing upon their bodies, that rendered it impossible for them to stir either toe or finger. It was a sensation similar to that so well-known, and so much dreaded, under the name of nightmare. It may have been the very same; and was, perhaps, brought on as much by the extreme weariness they all felt, as by the superincumbent weight of the sand. Their heads, lying higher than their bodies, were not so deeply buried under the drift; which, blown lightly over their faces, still permitted the atmosphere to pass through it. Otherwise their breathing would have been stopped altogether; and death must have been the necessary consequence. Whether it was a genuine nightmare or no, it was accompanied by all the horrors of this phenomenon. As they afterwards declared, all four felt its influence, each in his own way dreaming of some fearful fascination from which he could make no effort to escape. Strange enough, their dreams were different. Harry Blount thought he was falling over a precipice; Colin that a gigantic ogre had got hold of and was going to eat him up; while the young Hibernian fancied himself in the midst of a conflagration, a dwelling-house on fire, from which he could not get out! Old Bill's delusion was more in keeping with their situation, or at least with that out of which they had lately escaped. He simply supposed that he was submerged in the sea, and as he knew he could not swim, it was but natural for him to fancy that he was drowning. Still, he could make no struggle; and, as he would have done this, whether able to swim or not, his dream did not exactly resemble the real thing.