"What is it?" we asked eagerly. "What have you found out?"

"Peter," he said, turning to me, "you know what libration means; well,
it's libration that is going to save us. As Venus travels round the sun
she turns just once on her axis in making a complete circuit, the
consequence being, as you already know, that she has one side on which
the sun never rises while the other half is in perpetual daylight. But,
since her orbit is not a perfect circle, she travels a little faster than
the average during about half of her year and a little slower during the
other half, but, at the same time, her steady rotation on her axis never
varies. This produces the phenomenon that is called libration, the result
of which is that, along the border between the day and night hemispheres
there is a narrow strip where the sun rises and sets once in each of her
years, which are about two hundred and twenty-five of our days in length.
Within this strip the sun shines continuously for about sixteen weeks,
gradually rising during eight weeks and sinking during the following
eight. Then, during the next sixteen weeks, the strip lies in unceasing
night.

"Now the kind fates have willed that we should fall just within this
lucky strip. By the utmost good fortune after we passed the blazing peak
which so nearly wrecked us, we were carried on by the wind so far, before
the ascensional power of the car gave out, that we descended on the
sunward side of the crest of the range. The sun is now just beginning to
rise on the part of the strip where we are, and it will get higher for
several weeks to come. The result will be that a great melting of ice and
snow will occur here, and in this deep valley a river will form, flowing
off toward the sunward hemisphere, exactly where we want to go. I shall
take advantage of the torrent that will flow here and float down with it