Several causes contributed to the delightful coolness which renders the Matto Grosso one of the most attractive regions on the globe.

The abundance of water, the endless stretch of forest, with few llanos of any extent, and, above all, the elevation of the plateau produce a moderation of temperature not met with in the lowlands, less than twenty degrees further south.
But the explorers were weary and in need of rest.

It will be recalled that they found precious little opportunity for sleep during the preceding night, which marked the close of an unusually hard day's labor.

They would have rested could they have done so, and now that the chance seemed to present itself, they wisely decided to wait a few hours before beginning the last stretch of water which lay between them and the villages of the Murhapas.
The halt was made at the top of the rapids, where the boat was carefully replaced in the river, the fracture made by Ziffak's javelin repaired, and everything adjusted for the resumption of their voyage.
Then, with only the Professor on guard, the others lay down on their blankets and almost immediately sank into a deep, refreshing slumber.
Professor Grimcke, finding the care of the camp on his hands, took a careful survey of his surroundings, which were quite similar to those that had enclosed him many times before.
On both sides, stretched the almost endless Brazilian forest, within which a traveller might wander for weeks and months without coming upon any openings.

In front was the Xingu, smooth, swift, and winding through the wilderness in such form that he could see only a short distance up stream.