Making our meals chiefly of salt fish, we grew very thirsty, and did not dare venture down to the woods where the cocoa-nuts grew, lest we should be seen. But we thought we might creep round the mountain, until we came to the place where the hot spring fell towards the Red Rock, and there we filled some large leaves with the water, and let it stand until it cooled, and then drank it, without any harm. And as we returned to our hiding-place I chanced to see some pieces of that rock I have before mentioned, what Billy called the fizzy rock, that which belched forth great clouds of poisonous fume when it was touched with water. The sight of this set an idea jogging in my head, which I did not tell at that moment to Billy because of his natural impatience; but when it was dark, and we had got down safely to the place of the former night's watching, and assured ourselves from the men's talk that they had no present notion of leaving the island--at this time of night, I say, I communicated my notion to Billy, and he applauded it with great enthusiasm. As soon as ever the first glimmer of light came, therefore, we might have been seen very busy gathering lumps of this rock, which we piled in two heaps, one about the spring near the top of the mountain, the other about the spring that flowed down the lava bed. We worked very hard at this, and I observed with great satisfaction that the cloud of steam above the mountain was a trifle thicker this day than it had been for some time past. Then we waited until the men were at their breakfast (we could see them easily from the edge of the thicket, which commanded a view of the house and its surroundings), and when they were in the midst of it, we hasted to these springs, Billy to one and I to the other, and began to topple into them the fragments of rock which we had gathered, being exceeding careful to keep to the windward side. The wind was blowing, as it did nearly always, in the direction of the house, so that when the dense and filthy smoke rose from the rock we had cast into the water, it was carried away into the interior of the island. [Sidenote: A Stratagem]