Frank and Fred had plenty of time for studying the falls of the Madeira and making a short excursion into the forest in the vicinity, as another day was required for getting ready to start after the bargain had been concluded for the hire of the boat and its crew. We will refer to Fred's note-book for an account of what they saw and learned. "There is a village of Caripuna Indians," wrote Fred, "a little way inland from the falls, and we paid it a visit. Most of the men were away on a fishing excursion, and the few that remained did not have anything we could buy. We made them some presents, but did not stay long, as we wanted to see a rubber-tree, and the manner of collecting the India-rubber of commerce. "We had a guide from the Mojos village at the falls; he had been a collector of rubber, and spoke enough Spanish to enable us to understand his explanations. Since the surveys were made for the railway a good many Mojos Indians have settled here, and they do quite a business in collecting rubber and sending it down the river to market. [Illustration: BRANCH OF THE INDIA-RUBBER TREE.] "The rubber-trees are abundant on both sides of the river for a long distance in either direction. How far inland they may be found is not definitely known. The scientific name of the tree is _Siphonia elastica_, or _Siphonia cachucha_, but there are several other trees that produce the gum which is so largely used in American and European industry. An incision is made in the side of the tree, and a cup made of leaves and clay is so placed as to catch the juice which flows from the cut. In a few hours the cup is filled, and a man comes around with a large jar in which the juice is collected. "The liquid is about the consistency of milk, and contains from ten to twenty per cent. of gum. It is poured into shallow basins, very often into empty turtle-shells, and allowed to stand in the sun, by which a good deal of the liquid is evaporated. When it is about the thickness of ordinary cream it is poured into a turtle-shell, and an Indian sits down to convert the liquid into rubber. [Illustration: INDIA-RUBBER MAKING ON THE MADEIRA.] "He has a small fire made of palm nuts, and over the fire is an inverted jar with a hole in the bottom, through which the smoke ascends. He dips a paddle into the cream, and then holds it over the hole in the jar until it is dried by the heat, which must always be gentle, through fear of spoiling the rubber. When the gum is hardened he dips the paddle again, and again dries it; he repeats the process until the desired thickness is secured.