Our adventures and our troubles were alike over. We now experienced the incalculable contrast between descending a known and travelled river, and one that is utterly unknown. After four days we hired a rubber man to go with us as guide. We knew exactly what channels were passable when we came to the rapids, when the canoes had to unload, and where the carry-trails were. It was all child’s play compared to what we had gone through. We made long days’ journeys, for at night we stopped at some palm-thatched house, inhabited or abandoned, and therefore the men were spared the labor of making camp; and we bought ample food for them, so there was no further need of fishing and chopping down palms for the palm-tops. The heat of the sun was blazing; but it looked as if we had come back into the rainy season, for there were many heavy rains, usually in the afternoon, but sometimes in the morning or at night. The mosquitoes were sometimes rather troublesome at night. In the daytime the piums swarmed, and often bothered us even when we were in midstream.

For four days there were no rapids we could not run without unloading. Then, on the 19th, we got a canoe from Senhor Barboso. He was a most kind and hospitable man, who also gave us a duck and a chicken and some mandioc and six pounds of rice, and would take no payment; he lived in a roomy house with his dusky, cigar-smoking wife and his many children. The new canoe was light and roomy, and we were able to rig up a low shelter under which I could lie; I was still sick. At noon we passed the mouth of a big river, the Rio Branco, coming in from the left; this was about in latitude 9° 38′. Soon afterward we came to the first serious rapids, the Panela. We carried the boats past, ran down the empty canoes, and camped at the foot in a roomy house. The doctor bought a handsome trumpeter bird, very friendly and confiding, which was thenceforth my canoe companion.

We had already passed many inhabited⁠—and a still larger number of uninhabited⁠—houses. The dwellers were rubbermen, but generally they were permanent settlers also, homemakers, with their wives and children. Some, both of the men and women, were apparently of pure Negro blood, or of pure Indian or south European blood; but in the great majority all three strains were mixed in varying degrees. They were most friendly, courteous, and hospitable. Often they refused payment for what they could afford, out of their little, to give us. When they did charge, the prices were very high, as was but just, for they live back of the beyond, and everything costs them fabulously, save what they raise themselves. The cool, bare houses of poles and palm thatch contained little except hammocks and a few simple cooking utensils; and often a clock or sewing machine, or Winchester rifle, from our own country. They often had flowers planted, including fragrant roses. Their only livestock, except the dogs, were a few chickens and ducks. They planted patches of mandioc, maize, sugarcane, rice, beans, squashes, pineapples, bananas, lemons, oranges, melons, peppers; and various purely native fruits and vegetables, such as the kniabo⁠—a vegetable-fruit growing on the branches of a high bush⁠—which is cooked with meat. They get some game from the forest, and more fish from the river. There is no representative of the government among them⁠—indeed, even now their very existence is barely known to the governmental authorities; and the church has ignored them as completely as the state. When they wish to get married they have to spend several months getting down to and back from Manaos or some smaller city; and usually the first christening and the marriage ceremony are held at the same time. They have merely squatter’s right to the land, and are always in danger of being ousted by unscrupulous big men who come in late, but with a title technically straight. The land laws should be shaped so as to give each of these pioneer settlers the land he actually takes up and cultivates, and upon which he makes his home. The small homemaker, who owns the land which he tills with his own hands, is the greatest element of strength in any country.

These are real pioneer settlers. They are the true wilderness-winners. No continent is ever really conquered, or thoroughly explored, by a few leaders, or exceptional men, although such men can render great service. The real conquest, the thorough exploration and settlement, is made by a nameless multitude of small men of whom the most important are, of course, the homemakers. Each treads most of the time in the footsteps of his predecessors, but for some few miles, at some time or other, he breaks new ground; and his house is built where no house has ever stood before. Such a man, the real pioneer, must have no strong desire for social life and no need, probably no knowledge, of any luxury, or of any comfort save of the most elementary kind. The pioneer who is always longing for the comfort and luxury of civilization, and especially of great cities, is no real pioneer at all. These settlers whom we met were contented to live in the wilderness. They had found the climate healthy and the soil fruitful; a visit to a city was a very rare event, nor was there any overwhelming desire for it.

In short, these men, and those like them everywhere on the frontier between civilization and savagery in Brazil, are now playing the part played by our backwoodsmen when over a century and a quarter ago they began the conquest of the great basin of the Mississippi; the part played by the Boer farmers for over a century in South Africa, and by the Canadians when less than half a century ago they began to take possession of their Northwest. Every now and then someone says that the “last frontier” is now to be found in Canada or Africa, and that it has almost vanished. On a far larger scale this frontier is to be found in Brazil⁠—a country as big as Europe or the United States⁠—and decades will pass before it vanishes. The first settlers came to Brazil a century before the first settlers came to the United States and Canada. For three hundred years progress was very slow⁠—Portuguese colonial government at that time was almost as bad as Spanish. For the last half-century and over there has been a steady increase in the rapidity of the rate of development; and this increase bids fair to be constantly more rapid in the future.

The Paolistas, hunting for lands, slaves, and mines, were the first native Brazilians who, a hundred years ago, played a great part in opening to settlement vast stretches of wilderness. The rubber hunters have played a similar part during the last few decades. Rubber dazzled them, as gold and diamonds have dazzled other men and driven them forth to wander through the wide waste spaces of the world. Searching for rubber they made highways of rivers the very existence of which was unknown to the governmental authorities, or to any map-makers. Whether they succeeded or failed, they everywhere left behind them settlers, who toiled, married, and brought up children. Settlement began; the conquest of the wilderness entered on its first stage.

On the 20th we stopped at the first store, where we bought, of course at a high price, sugar and tobacco for the camaradas. In this land of plenty the camaradas over-ate, and sickness was as rife among them as ever. In Cherrie’s boat he himself and the steersman were the only men who paddled strongly and continuously. The storekeeper’s stock of goods was very low, only what he still had left from that brought in nearly a year before; for the big boats, or batelãos⁠—batelóns⁠—had not yet worked as far upstream. We expected to meet them somewhere below the next rapids, the Inferno. The trader or rubber man brings up his year’s supply of goods in a batelão, starting in February and reaching the upper course of the river early in May, when the rainy season is over. The parties of rubber-explorers are then equipped and provisioned; and the settlers purchase certain necessities, and certain things that strike them as luxuries. This year the Brazil-nut crop on the river had failed, a serious thing for all explorers and wilderness wanderers.

On the 20th we made the longest run we had made, fifty-two kilometres. Lyra took observations where we camped; we were in latitude 8° 49′. At this camping-place the great, beautiful river was a little over three hundred metres wide. We were in an empty house. The marks showed that in the high water, a couple of months back, the river had risen until the lower part of the house was flooded. The difference between the level of the river during the floods and in the dry season is extraordinary.

On the 21st we made another good run, getting down to the Inferno rapids, which are in latitude 8° 19′ south. Until we reached the Cardozo we had run almost due north; since then we had been running a little west of north. Before we reached these rapids we stopped at a large, pleasant thatch house, and got a fairly big and roomy as well as light boat, leaving both our two smaller dugouts behind. Above the rapids a small river, the Madeirainha, entered from the left. The rapids had a fall of over ten metres, and the water was very wild and rough. Met with for the first time, it would doubtless have taken several days to explore a passage and, with danger and labor, get the boats down. But we were no longer exploring, pioneering, over unknown country. It is easy to go where other men have prepared the way. We had a guide; we took our baggage down by a carry three-quarters of a kilometre long; and the canoes were run through known channels the following morning. At the foot of the rapids was a big house and store; and camped at the head were a number of rubber-workers, waiting for the big boats of the head rubbermen to work their way up from below. They were a reckless set of brown daredevils. These men lead hard lives of labor and peril; they continually face death themselves, and they think little of it in connection with others. It is small wonder that they sometimes have difficulties with the tribes of utterly wild Indians with whom they are brought in contact, although there is a strong Indian strain in their own blood.

The following morning, after the empty canoes had been run down, we started, and made a rather short afternoon’s journey. We had to take the baggage by one rapids. We camped in an empty house, in the rain. Next day we ran nearly fifty kilometres, the river making a long sweep to the west. We met half a dozen batelãos making their way upstream, each with a crew of six or eight men; and two of them with women and children in addition. The crew were using very long poles, with crooks, or rather the stubs of cut branches which served as crooks, at the upper end. With these they hooked into the branches and dragged themselves up along the bank, in addition to poling where the depth permitted it. The river was as big as the Paraguay at Corumbá; but, in striking contrast to the Paraguay, there were few waterbirds. We ran some rather stiff rapids, the Infernino, without unloading, in the morning. In the evening we landed for the night at a large, open, shed-like house, where there were two or three pigs, the first livestock we had seen other than poultry and ducks. It was a dirty place, but we got some eggs.

The following day, the 24th, we ran down some fifty kilometres to the Carupanan rapids, which by observation Lyra found to be in latitude 7° 47′. We met several batelãos, and the houses on the bank showed that the settlers were somewhat better off than was the case farther up. At the rapids was a big store, the property of Senhor Caripe, the wealthiest rubber man who works on this river; many of the men we met were in his employ. He has himself risen from the ranks. He was most kind and hospitable, and gave us another boat to replace the last of our shovel-nosed dugouts. The large, open house was cool, clean, and comfortable.

With these began a series of half a dozen sets of rapids, all coming within the next dozen kilometres, and all offering very real obstacles. At one we saw the graves of four men who had perished therein; and many more had died whose bodies were never recovered; the toll of human life had been heavy. Had we been still on an unknown river, pioneering our own way, it would doubtless have taken us at least a fortnight of labor and peril to pass. But it actually took only a day and a half. All the channels were known, all the trails cut. Senhor Caripe, a first-class waterman, cool, fearless, and brawny as a bull, came with us as guide. Half a dozen times the loads were taken out and carried down. At one cataract the canoes were themselves dragged overland; elsewhere they were run down empty, shipping a good deal of water. At the foot of the cataract, where we dragged the canoes overland, we camped for the night. Here Kermit shot a big cayman. Our camp was alongside the graves of three men who at this point had perished in the swift water.

Senhor Caripe told us many strange adventures of rubber-workers he had met or employed. One of his men, working on the Gy-Paraná, got lost and after twenty-eight days found himself on the Madeirainha, which he thus discovered. He was in excellent health, for he had means to start a fire, and he found abundance of Brazil-nuts and big land-tortoises. Senhor Caripe said that the rubbermen now did not go above the ninth degree, or thereabouts, on the upper Aripuanan proper, having found the rubber poor on the reaches above. A year previously five rubbermen, Mundurucu Indians, were working on the Corumbá at about that level. It is a difficult stream to ascend or descend. They made excursions into the forest for days at a time after caoutchouc. On one such trip, after fifteen days they, to their surprise, came out on the Aripuanan. They returned and told their “patron” of their discovery; and by his orders took their caoutchouc overland to the Aripuanan, built a canoe, and ran down with their caoutchouc to Manaos. They had now returned and were working on the upper Aripuanan. The Mundurucus and Brazilians are always on the best terms, and the former are even more inveterate enemies of the wild Indians than are the latter.

By mid-forenoon on April 26 we had passed the last dangerous rapids. The paddles were plied with hearty good will, Cherrie and Kermit, as usual, working like the camaradas, and the canoes went dancing down the broad, rapid river. The equatorial forest crowded on either hand to the water’s edge; and, although the river was falling, it was still so high that in many places little islands were completely submerged, and the current raced among the trunks of the green trees. At one o’clock we came to the mouth of the Castanho proper, and in sight of the tent of Lieutenant Pyrineus, with the flags of the United States and Brazil flying before it; and, with rifles firing from the canoes and the shore, we moored at the landing of the neat, soldierly, well kept camp. The upper Aripuanan, a river of substantially the same volume as the Castanho, but broader at this point, and probably of less length, here joined the Castanho from the east, and the two together formed what the rubbermen called the lower Aripuanan. The mouth of this was indicated, and sometimes named, on the maps, but only as a small and unimportant stream.

We had been two months in the canoes; from the 27th of February to the 26th of April. We had gone over 750 kilometres. The river from its source, near the thirteenth degree, to where it became navigable and we entered it, had a course of some 200 kilometres⁠—probably more, perhaps 300 kilometres. Therefore we had now put on the map a river nearly 1,000 kilometres in length of which the existence was not merely unknown but impossible if the standard maps were correct. But this was not all. It seemed that this river of 1,000 kilometres in length was really the true upper course of the Aripuanan proper, in which case the total length was nearly 1,500 kilometres. Pyrineus had been waiting for us over a month, at the junction of what the rubbermen called the Castanho and of what they called the upper Aripuanan. (He had no idea as to which stream we would appear upon, or whether we would appear upon either.) On March 26 he had measured the volume of the two, and found that the Castanho, although the narrower, was the deeper and swifter, and that in volume it surpassed the other by 84 cubic metres a second. Since then the Castanho had fallen; our measurements showed it to be slightly smaller than the other; the volume of the river after the junction was about 4,500 cubic metres a second. This was in 7° 34′.

We were glad indeed to see Pyrineus and be at his attractive camp. We were only four hours above the little river hamlet of São João, a port of call for rubber-steamers, from which the larger ones go to Manaos in two days. These steamers mostly belong to Senhor Caripe. From Pyrineus we learned that Lauriadó and Fiala had reached Manaos on March 26. On the swift water in the gorge of the Papagaio Fiala’s boat had been upset and all his belongings lost, while he himself had narrowly escaped with his life. I was glad indeed that the fine and gallant fellow had escaped. The Canadian canoe had done very well. We were no less rejoiced to learn that Amilcar, the head of the party that went down the Gy-Paraná, was also all right, although his canoe too had been upset in the rapids, and his instruments and all his notes lost. He had reached Manaos on April 10. Fiala had gone home. Miller was collecting near Manaos. He had been doing capital work.

The piranhas were bad here, and no one could bathe. Cherrie, while standing in the water close to the shore, was attacked and bitten; but with one bound he was on the bank before any damage could be done.

We spent a last night under canvas, at Pyrineus’ encampment. It rained heavily. Next morning we all gathered at the monument which Colonel Rondon had erected, and he read the orders of the day. These recited just what had been accomplished: set forth the fact that we had now by actual exploration and investigation discovered that the river whose upper portion had been called the Dúvida on the maps of the Telegraphic Commission and the unknown major part of which we had just traversed, and the river known to a few rubbermen, but to no one else, as the Castanho, and the lower part of the river known to the rubbermen as the Aripuanan (which did not appear on the maps save as its mouth was sometimes indicated, with no hint of its size) were all parts of one and the same river; and that by order of the Brazilian Government this river, the largest affluent of the Madeira, with its source near the 13th degree and its mouth a little south of the 5th degree, hitherto utterly unknown to cartographers and in large part utterly unknown to any save the local tribes of Indians, had been named the Rio Roosevelt.

We left Rondon, Lyra, and Pyrineus to take observations, and the rest of us embarked for the last time on the canoes, and, borne swiftly on the rapid current, we passed over one set of not very important rapids and ran down to Senhor Caripe’s little hamlet of São João, which we reached about one o’clock on April 27, just before a heavy afternoon rain set in. We had run nearly eight hundred kilometres during the sixty days we had spent in the canoes. Here we found and boarded Pyrineus’s river steamer, which seemed in our eyes extremely comfortable. In the senhor’s pleasant house we were greeted by the senhora, and they were both more than thoughtful and generous in their hospitality. Ahead of us lay merely thirty-six hours by steamer to Manaos. Such a trip as that we had taken tries men as if by fire. Cherrie had more than stood every test; and in him Kermit and I had come to recognize a friend with whom our friendship would never falter or grow less.

Early the following afternoon our whole party, together with Senhor Caripe, started on the steamer. It took us a little over twelve hours’ swift steaming to run down to the mouth of the river on the upper course of which our progress had been so slow and painful; from source to mouth, according to our itinerary and to Lyra’s calculations, the course of the stream down which we had thus come was about 1,500 kilometres in length⁠—about 900 miles, perhaps nearly 1,000 miles⁠—from its source near the 13th degree in the highlands to its mouth in the Madeira, near the 5th degree. Next morning we were on the broad sluggish current of the lower Madeira, a beautiful tropical river. There were heavy rainstorms, as usual, although this is supposed to be the very end of the rainy season. In the afternoon we finally entered the wonderful Amazon itself, the mighty river which contains one tenth of all the running water of the globe. It was miles across, where we entered it; and indeed we could not tell whether the farther bank, which we saw, was that of the mainland or an island. We went up it until about midnight, then steamed up the Rio Negro for a short distance, and at one in the morning of April 30 reached Manaos.

Manaos is a remarkable city. It is only three degrees south of the equator. Sixty years ago it was a nameless little collection of hovels, tenanted by a few Indians and a few of the poorest class of Brazilian peasants. Now it is a big, handsome modern city, with opera-house, tramways, good hotels, fine squares and public buildings, and attractive private houses. The brilliant coloring and odd architecture give the place a very foreign and attractive flavor in northern eyes. Its rapid growth to prosperity was due to the rubber trade. This is now far less remunerative than formerly. It will undoubtedly in some degree recover; and in any event the development of the immensely rich and fertile Amazonian valley is sure to go on, and it will be immensely quickened when closer connections are made with the Brazilian highland country lying south of it.

Here we found Miller, and glad indeed we were to see him. He had made good collections of mammals and birds on the Gy-Paraná, the Madeira, and in the neighborhood of Manaos; his entire collection of mammals was really noteworthy. Among them was the only sloth any of us had seen on the trip. The most interesting of the birds he had seen was the hoatzin. This is a most curious bird of very archaic type. Its flight is feeble, and the naked young have spurs on their wings, by the help of which they crawl actively among the branches before their feathers grow. They swim no less easily, at the same early age. Miller got one or two nests, and preserved specimens of the surroundings of the nests; and he made exhaustive records of the habits of the birds. Near Megasso a jaguar had killed one of the bullocks that were being driven along for food. The big cat had not seized the ox with its claws by the head, but had torn open its throat and neck.

Everyone was most courteous at Manaos, especially the governor of the state and the mayor of the city. Mr. Robiliard, the British consular representative, and also the representative of the Booth line of steamers, was particularly kind. He secured for us passages on one of the cargo boats of the line to Para, and thence on one of the regular cargo-and-passenger steamers to Barbados and New York. The Booth people were most courteous to us.

I said goodbye to the camaradas with real friendship and regret. The parting gift I gave to each was in gold sovereigns; and I was rather touched to learn later that they had agreed among themselves each to keep one sovereign as a medal of honor and token that the owner had been on the trip. They were a fine set, brave, patient, obedient, and enduring. Now they had forgotten their hard times; they were fat from eating, at leisure, all they wished; they were to see Rio de Janeiro, always an object of ambition with men of their stamp; and they were very proud of their membership in the expedition.

Later, at Belén, I said goodbye to Colonel Rondon, Doctor Cajazeira, and Lieutenant Lyra. Together with my admiration for their hardihood, courage, and resolution, I had grown to feel a strong and affectionate friendship for them. I had become very fond of them; and I was glad to feel that I had been their companion in the performance of a feat which possessed a certain lasting importance.

On May 1 we left Manaos for Belén⁠—Para, as until recently it was called. The trip was interesting. We steamed down through tempest and sunshine; and the towering forest was dwarfed by the giant river it fringed. Sunrise and sunset turned the sky to an unearthly flame of many colors above the vast water. It all seemed the embodiment of loneliness and wild majesty. Yet everywhere man was conquering the loneliness and wresting the majesty to his own uses. We passed many thriving, growing towns; at one we stopped to take on cargo. Everywhere there was growth and development. The change since the days when Bates and Wallace came to this then poor and utterly primitive region is marvellous. One of its accompaniments has been a large European, chiefly south European, immigration. The blood is everywhere mixed; there is no color line, as in most English-speaking countries, and the Negro and Indian strains are very strong; but the dominant blood, the blood already dominant in quantity, and that is steadily increasing its dominance, is the olive-white.

Only rarely did the river show its full width. Generally we were in channels or among islands. The surface of the water was dotted with little islands of floating vegetation. Miller said that much of this came from the lagoons such as those where he had been hunting, beside the Solimoens⁠—lagoons filled with the huge and splendid Victoria lily, and with masses of water hyacinths. Miller, who was very fond of animals and always took much care of them, had a small collection which he was bringing back for the Bronx Zoo. An agouti was so bad-tempered that he had to be kept solitary; but three monkeys, big, middle-sized, and little, and a young peccary formed a happy family. The largest monkey cried, shedding real tears, when taken in the arms and pitied. The middle-sized monkey was stupid and kindly, and all the rest of the company imposed on it; the little monkey invariably rode on its back, and the peccary used it as a head pillow when it felt sleepy.

Belén, the capital of the state of Para, was an admirable illustration of the genuine and almost startling progress which Brazil has been making of recent years. It is a beautiful city, nearly under the equator. But it is not merely beautiful. The docks, the dredging operations, the warehouses, the stores and shops, all tell of energy and success in commercial life. It is as clean, healthy, and well policed a city as any of the size in the north temperate zone. The public buildings are handsome, the private dwellings attractive; there are a fine opera-house, an excellent tramway system, and a good museum and botanical gardens. There are cavalry stables, where lights burn all night long to protect the horses from the vampire bats. The parks, the rows of palms and mango-trees, the open-air restaurants, the gay life under the lights at night, all give the city its own special quality and charm. Belén and Manaos are very striking examples of what can be done in the mid-tropics. The governor of Para and his charming wife were more than kind.

Cherrie and Miller spent the day at the really capital zoological gardens, with the curator, Miss Snethlage. Miss Snethlage, a German lady, is a first rate field and closet naturalist, and an explorer of note, who has gone on foot from the Xingu to the Tapajos. Most wisely she has confined the Belén zoo to the animals of the lower Amazon valley, and in consequence I know of no better local zoological gardens. She has an invaluable collection of birds and mammals of the region; and it was a privilege to meet her and talk with her.

We also met Professor Farrabee, of the University of Pennsylvania, the ethnologist. He had just finished a very difficult and important trip, from Manaos by the Rio Branco to the highlands of Guiana, across them on foot, and down to the seacoast of British Guiana. He is an admirable representative of the men who are now opening South America to scientific knowledge.

On May 7 we bade goodbye to our kind Brazilian friends and sailed northward for Barbados and New York.

Zoologically the trip had been a thorough success. Cherrie and Miller had collected over twenty-five hundred birds, about five hundred mammals, and a few reptiles, batrachians, and fishes. Many of them were new to science; for much of the region traversed had never previously been worked by any scientific collector.

Of course, the most important work we did was the geographic work, the exploration of the unknown river, undertaken at the suggestion of the Brazilian Government, and in conjunction with its representatives. No piece of work of this kind is ever achieved save as it is based on long continued previous work. As I have before said, what we did was to put the cap on the pyramid that had been built by Colonel Rondon and his associates of the Telegraphic Commission during the six previous years. It was their scientific exploration of the chapadão, their mapping the basin of the Juruena, and their descent of the Gy-Paraná that rendered it possible for us to solve the mystery of the River of Doubt.

The work of the commission, much the greatest work of the kind ever done in South America, is one of the many, many achievements which the republican government of Brazil has to its credit. Brazil has been blessed beyond the average of her Spanish-American sisters because she won her way to republicanism by evolution rather than revolution. They plunged into the extremely difficult experiment of democratic, of popular, self-government, after enduring the atrophy of every quality of self-control, self-reliance, and initiative throughout three withering centuries of existence under the worst and most foolish form of colonial government, both from the civil and the religious standpoint, that has ever existed. The marvel is not that some of them failed, but that some of them have eventually succeeded in such striking fashion. Brazil, on the contrary, when she achieved independence, first exercised it under the form of an authoritative empire, then under the form of a liberal empire. When the republic came, the people were reasonably ripe for it. The great progress of Brazil⁠—and it has been an astonishing progress⁠—has been made under the republic. I could give innumerable examples and illustrations of this. The change that has converted Rio de Janeiro from a picturesque pesthole into a singularly beautiful, healthy, clean, and efficient modern great city is one of these. Another is the work of the Telegraphic Commission.

We put upon the map a river some fifteen hundred kilometres in length, of which the upper course was not merely utterly unknown to, but unguessed at by, anybody; while the lower course, although known for years to a few rubbermen, was utterly unknown to cartographers. It is the chief affluent of the Madeira, which is itself the chief affluent of the Amazon.

The source of this river is between the 12th and 13th parallels of latitude south and the 59th and 60th degrees of longitude west from Greenwich. We embarked on it at about latitude 12° 1′ south, and about longitude 60° 15′ west. After that its entire course lay between the 60th and 61st degrees of longitude, approaching the latter most closely about latitude 8° 15′. The first rapids we encountered were in latitude 11° 44′, and in uninterrupted succession they continued for about a degree, without a day’s complete journey between any two of them. At 11° 23′ the Rio Kermit entered from the left, at 11° 22′ the Rio Marciano Avila from the right, at 11° 18′ the Taunay from the left, at 10° 58′ the Cardozo from the right. In 10° 24′ we encountered the first rubbermen. The Rio Branco entered from the left at 9° 38′. Our camp at 8° 49′ was nearly on the boundary between Matto Grosso and Amazonas. The confluence with the Aripuanan, which joined from the right, took place at 7° 34′. The entrance into the Madeira was at about 5° 20′ (this point we did not determine by observation, as it is already on the maps). The stream we had followed down was from the river’s highest sources; we had followed its longest course.