There was no indication of it in 1877, during the weeks that preceded and followed the summer solstice of that world.

A single isolated case presented itself in 1879.

On the 26th of December, this year--a little before the spring equinox, which occurred on Mars on the 21st of January, 1880--I noticed the doubling of the Nile [a canal thus named] between the Lakes of the Moon and the Ceraunic Gulf.

These two regular, equal, and parallel lines caused me, I confess, a profound surprise, the more so because a few days earlier, on the 23d and the 24th of December, I had carefully observed that very region without discovering anything of the kind.
"I awaited with curiosity the return of the planet in 1881, to see if an analogous phenomenon would present itself in the same place, and I saw the same thing reappear on the 11th of January, 1882, one month after the spring equinox--which occurred on the 8th of December, 1881.

The duplication was still more evident at the end of February.