Excerpt: The blood-red sun was sinking beyond the distant Geral Mountains, when a canoe, containing four white men and three natives, came to a halt a thousand miles from the mighty Amazon, in the upper waters of the Xingu River, near the great table-land of Matto Grosso.

It was hard work, forcing the long shallow boat against the rapid current of the stream, whose unknown source is somewhere among the famous diamond regions of Brazil. It was plain sailing for three hundred leagues from the Amazon, from whose majestic volume the little party of explorers...