For two days we made our way up a river, dark in colour, but clean, so that one could usually see the bottom. The woods on either side were primeval, and we had no great difficulty in carrying our canoes through them. How shall I ever forget the solemn mystery of it? The height of the trees and the thickness of the trunks were greater than anything that I could have ever imagined… We could dimly see the spot where they threw out their side-branches into Gothic upward curves. As we walked noiselessly stepping on the thick, soft carpet of vegetation, we were spellbound, and even Professor Challenger’s full-chested voice sank into a whisper. Alone, I should have been ignorant of the names of these plants, but our men of science pointed out the cedars, the great silk cotton trees, and the redwood trees. Animal life was rather poor, but a constant movement above our heads told of the world of snakes and monkeys, birds, which lived in the sunshine, and looked down at our tiny, dark figures. At dawn and at sunset the howler monkeys screamed together and the parrots broke into shrill chatter. Once some creature, an ant-eater or a bear, went clumsily in the shadows. It was the only sign of earth life which I saw in this great Amazonian forest.

And yet we felt that human life itself was not far from us. On the third day out we heard a beating in the air, rhythmic and solemn. The two boats were floating when we heard it, and our Indians remained motionless, listening with expressions of terror on their faces.

“What is it?” I asked.

“Drums,” said Lord John, carelessly; “War drums. I have heard them before.”

“Yes, sir, war drums,” said Gomez, the half-breed. “Wild Indians; they watch us every mile of the way, kill us if they can.”

“How can they watch us?” I asked, gazing into the dark.

“The Indians know. They have their own way. They watch us. They talk the drum talk to each other. Kill us if they can.”

By the afternoon of that day at least six or seven drums were beating from various points. Sometimes they beat quickly, sometimes slowly, sometimes in obvious question and answer. There was something nerve-shaking and menacing in that constant mutter, “We will kill you if we can. We will kill you if we can.” No one ever moved in the silent woods. All the peace of quiet Nature lay in that dark curtain of vegetation, but away from behind there came the message from our fellow-man. “We will kill you if we can,” said the men in the east. “We will kill you if we can,” said the men in the north.

Their menace reflected in the faces of our coloured companions. I learned, however, that both Summerlee and Challenger possessed that highest type of bravery, the bravery of the scientific mind. It is decreed by a merciful Nature that the human brain cannot think of two things simultaneously, so that if it is devoted to science it has no room for other personal considerations. All day our two Professors watched every bird and every plant and argued a lot, with no sense of danger as if they were seated together in the smoking-room of the Royal Society’s Club in St. James’s Street.

About three o’clock in the afternoon we came to a very dangerous rapid, in which Professor Challenger had suffered disaster on his first journey. Before evening we had successfully passed the rapids, and made our way some ten miles above them, where we stayed for the night. At this point we had come not less than a hundred miles up the tributary from the main stream.

In the morning Professor Challenger started scanning each bank of the river. Suddenly he gave an exclamation of satisfaction and showed us a tree.