down in wonder at our tiny, dark, stumbling figures in the obscure depths immeasurably below them.  At dawn and at sunset the howler monkeys screamed together and the parrakeets broke into shrill chatter, but during the hot hours of the day only the full drone of insects, like the beat of a distant surf, filled the ear, while nothing moved amid the solemn vistas of stupendous trunks, fading away into the darkness which held us in.  Once some bandy-legged, lurching creature, an ant-eater or a bear, scuttled clumsily amid the shadows.  It was the only sign of earth life which I saw in this great Amazonian forest.

And yet there were indications that even human life itself was not far from us in those mysterious recesses.  On the third day out we were aware of a singular deep throbbing in the air, rhythmic and solemn, coming and going fitfully throughout the morning.  The two boats were paddling within a few yards of each other when first we heard it, and our Indians remained motionless, as if they had been turned to bronze, listening intently with expressions of terror upon their faces.

“What is it, then?” 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, bravos, not mansos; they watch us every mile of the way; kill us if they can.”

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

The half-breed shrugged his broad shoulders.

“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—­my pocket diary shows me that it was Tuesday, August 18th—­at least six or seven drums were throbbing from various points.  Sometimes they beat quickly, sometimes slowly, sometimes in obvious question and answer, one far to the east breaking out in a high staccato rattle, and being followed after a pause by a deep roll from the north.  There was something indescribably nerve-shaking and menacing in that constant mutter, which seemed to shape itself into the very syllables of the half-breed, endlessly repeated, “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 and soothing of quiet Nature lay in that dark curtain of vegetation, but away from behind there came ever the one 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.