After we were rested and refreshed, and had sampled the mangoes that had fallen from a tree near the house, Mr. Aiken took us in his automobile up into the famous Iao Valley, at the mouth of which Wailuku is situated. It is a deep, striking chasm carved out of the mountain by the stream, rank with verdure of various kinds, and looked down upon by sharp peaks and ridges five or six thousand feet high. We soon reached the clear rapid, brawling stream, as bright as a Catskill mountain trout brook, and after a mile or two along its course we came to the end of the road, where we left the machine and took a trail that wound onward and upward over a slippery surface and through dripping bushes, for we here began to reach the skirts of the little showers that almost constantly career over and about the interior of these mountains. I neither saw nor heard a bird or other live thing. Guava apples lay on the ground all along the trail, and one could eat them and not make faces. Some of the sharp, knife-blade ridges that cut down toward us from the higher peaks were very startling, and so steep and high that they could be successfully scaled only by the aid of ropes and ladders. A more striking object-lesson in erosion by rain would be hard to find. There were no naked rocks; short, thick vegetation covered even the steepest slopes, and the vegetable acids which this generated, and the perpetual rains, weathered the mountains down. It soon became so wet that we stopped far short of the head of the valley, and turned back. I wished to look into the great, deep, green amphitheatre which seems to lie at the head, but had glimpses of it only from a distance. How many millenniums will it be, I said to myself, before erosion will have completed its work here, and these thin, high mountain-walls will be in ruins? Surely not many.