It was as big as his finger-nail, and shone and gleamed in the sunlight, sparkling and reflecting the beams. Its value must be very great. But well he knew how dangerous it would be to exhibit it; on some pretext or other he would be thrown into prison, and the gem seized. It must be hidden with the greatest care till he could produce it in Thyma Castle, when the Baron would protect it. Felix regretted now that he had not searched further; perhaps he might have found other treasures for Aurora; the next instant he repudiated his greed, and was only thankful that he had escaped with his life. He wondered and marvelled that he had done so, it was so well known that almost all who had ventured in had perished. Reflecting on the circumstances which had accompanied his entrance to the marshes, the migration of the birds seemed almost the most singular. They were evidently flying from some apprehended danger, and that most probably would be in the air. The gale at that time, however, was blowing in a direction which would appear to ensure safety to them; into, and not out of, the poisonous marshes. Did they, then, foresee that it would change? Did they expect it to veer like a cyclone and presently blow east with the same vigour as it then blew west? That would carry the vapour from the inky waters out over the sweet Lake, and might even cause the foul water itself to temporarily encroach on the sweet. The more he thought of it, the more he felt convinced that this was the explanation; and, as a fact, the wind, after dropping, did arise again and blow from the east, though, as it happened, not with nearly the same strength. It fell, too, before long, fortunately for him. Clearly the birds had anticipated a cyclone, and that the wind turning would carry the gases out upon them to their destruction. They had therefore hurried away, and the fishes had done the same. The velocity of the gale which had carried him into the black waters had proved his safety, by driving before it the thicker and most poisonous portion of the vapour, compressing it towards the east, so that he had entered the dreaded precincts under favourable conditions. When it dropped, while he was on the black island, he soon began to feel the effect of the gases rising imperceptibly from the soil, and had he not had the good fortune to escape so soon, no doubt he would have fallen a victim. He could not congratulate himself sufficiently upon his good fortune. The other circumstances appeared to be due to the decay of the ancient city, to the decomposition of accumulated matter, to phosphorescence and gaseous exhalations. The black rocks that crumbled at a touch were doubtless the remains of ancient buildings saturated with the dark water and vapours. Inland similar remains were white, and resembled salt.