At once we entered the woods which are on its banks, and everyone set to work in good earnest to cut down trees, in order to construct _piperies_, with which to descend the river. The reader may perhaps imagine that these piperies were some kind of comfortable boat to carry us pleasantly along the stream, but they were anything but this. We joined together four or five trunks of a kind of tree with light floating wood, merely stripping off their bark, and binding them, instead of cord, with a climbing plant growing in those forests, and embracing the trees like ivy, and when these structures, each large enough to hold two men (and in appearance something like huge wicker baskets) were completed, vessels and crew were ready. [Illustration] The safest plan was to stand upright in them, armed with long poles to push them off from the rocks, against which the fierce current every moment threatened to dash them. As it was, they sank two or three feet deep in the water, so that we were nearly always immersed up to our waists. This river rises in the mountains of Segovia, and falls into the sea at Cape Gracia a Dios, after having flowed for a long distance, with frightful rapidity, among an infinite number of huge rocks, and between the most terrible precipices imaginable. We had to pass more than a hundred cataracts great and small, and there were three which the most daring of us could not look at without turning giddy with fear, when we saw and heard the water plunging from such a height into those horrible gulfs. Everything was so fearful that only those who have experienced it can imagine it; as for me, though I shall all my life have my memory full of pictures of the perils of that voyage, it would be impossible for me to give any idea of it which would not be far below the reality. We let ourselves go with the current, so rapid that often, in spite of our resistance, it bore us into foaming whirlpools, where we were engulfed with our pieces of wood. But happily before the greatest cataracts, and also just beyond them, there was a basin of calm water, which made it possible for us to gain the bank, drawing our piperies after us. Then, taking out of them whatever valuables we had there, we descended with these, leaping from rock to rock till we had reached the foot of the cataract. Then one of us would return and throw the piperies, which we had left behind, down into the flood--and we below caught them as they descended. Sometimes, indeed, we failed to catch them, and had to make new ones.