Happily for the engineer and his companions the weather was beautiful, the atmosphere tranquil; for a high breeze at an elevation of three thousand feet would have hindered their proceedings.

The purity of the sky at the zenith was felt through the transparent air.

A perfect calm reigned around them.

They could not see the sun, then hid by the vast screen of the upper cone, which masked the half-horizon of the west, and whose enormous shadow stretching to the shore increased as the radiant luminary sank in its diurnal course.

Vapor--mist rather than clouds--began to appear in the east, and assume all the prismatic colors under the influence of the solar rays.
Five hundred feet only separated the explorers from the plateau, which they wished to reach so as to establish there an encampment for the night, but these five hundred feet were increased to more than two miles by the zigzags which they had to describe.