They have a breadth of two degrees, or 120 kilometres [74 miles], and several extend over a length of eighty degrees, or 4,800 kilometres [nearly 3,000 miles].

Their tint is very nearly the same as that of the seas, usually a little lighter.

Every canal terminates at both its extremities in a sea, or in another canal; there is not a single example of one coming to an end in the midst of dry land.
"This is not all.

In certain seasons these canals become double.

This phenomenon seems to appear at a determinate epoch, and to be produced simultaneously over the entire surface of the planet's continents.