330 THROUGH THE BRAZILIAN WILDERNESS 



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 rubber-men 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 thir- 

 teenth 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 rubber-men 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 mea- 

 sured the volume of the two, and found that the Castanho, 

 although the narrower, was the deeper and swifter, and 



