five o’clock
If he did , he did not show it , for his manner changed not in the least . Satisfied with their mutual explanation , Manoel and Benito promised to keep him in sight without doing anything to awaken his suspicions . During the following days the jangada passed on the right the mouths of the rivers Camara , Aru , and Yuripari , whose waters instead of flowing into the Amazon run off to the south to feed the Rio des Purus , and return by it into the main river . At five o'clock on the evening of the 10th of August they put into the island of Cocos . They there passed a _ `` seringal . '' _ This name is applied to a caoutchouc plantation , the caoutchouc being extracted from the _ `` seringueira '' _ tree , whose scientific name is _ siphonia elastica . _ It is said that , by negligence or bad management , the number of these trees is decreasing in the basin of the Amazon , but the forests of seringueira trees are still very considerable on the banks of the Madeira , Purus , and other tributaries .