However, he agreed to my proposal, and we carried a rock between us, with a great deal of sweating, up to where the fallen trees lay, and then Billy says, "Ain't we fools!" and showed me that we could save a deal of labour by fastening strands of creeper to the second rock, and dragging it up instead of carrying it in our arms. This being done we cut two stout poles, which took us a long time, and then, putting the rocks one on either side of the first trunk, we took a pole each, and, resting them on the rocks, put the one end under the tree and pressed heavily on the other, and so contrived to lift the weight which our unaided strength was quite unequal to. I do not mean that we had never seen levers before, but we might never have thought of them unless Billy had prised up the rock after that crab. The use of levers was indeed a mystery to him, I mean the explanation of them, he saying that we were no stronger than before, and there was certainly no strength in two dead poles, and when I reminded him of the pulleys and the windlass on board ship, which also helped to raise things, he said that poles were not pulleys, nor a windlass neither, and he didn't see what that had to do with it. However, there was the trunk lifted, and while I held it so with my pole, Billy slipped a roller under it, and working thus from the end towards the middle, we brought the roller along by degrees, and then found that we could slip the second roller under the other end without the help of the poles. Then, with much pushing and hauling, we set the trunk a-moving on the rollers down the slope. It was still hard work enough, for where the earth was soft, the rollers sank into it under the heavy weight of the tree, and when we came to a part that was hard and pretty smooth, the trunk set to a-rolling so fast that it almost ran away with us, and Billy, who was in front, was very nearly sent headlong down, which would have been very terrible if he had fallen plump into our grate. We brought the other three trunks down to our plateau in the same way, and thus had the four stout posts which we intended for the corners of our house, though there was a great deal to be done to them before they could be erected. They were about the same thickness, being sixteen or eighteen inches across, but not the same length, and we had first to make them equal, which took us a long time; I think we were ten days at the work. When we had finished it, the trunks were about fourteen feet long, that being the height we had determined on for our house, allowing for some portion of the posts to be driven into the earth. We did not peel the bark off the trees, but left it on, thinking it would do no harm. [Sidenote: Choosing a Site]