The climb down the steep slope into the chasm was swifter than that up the canyon but no more pleasant. Carrying a heavy pack down such a grade exerted a torturous strain upon the backs of the legs.

The heat increased steadily as they descended. They reached the floor of the valley the next day and the noonday heat was so great that Humbolt wondered if they might not have trapped themselves into what the summer would soon transform into a monstrous oven where no life at all could exist. There could never be any choice, of course⁠—the mountains were passable only when the weather was hot.

The floor of the valley was silt, sand and gravel⁠—they would find nothing there. They set out on a circuit of the chasm’s walls, following along close to the base.