There is nothing analogous in terrestrial geography.
Everything indicates that here there is an organization special to the planet Mars, probably connected with the course of its seasons."[1] [Footnote 1: L'Astronomie, vol.i, 1882, pp.

217 _et seq._] Schiaparelli adds that he took every precaution to avoid the least suspicion of illusion.

"I am absolutely sure," he says, "of what I have observed." I have quoted his statement, especially about the duplication of the canals, at so much length, both on account of its intrinsic interest and because it has many times been argued that this particular phenomenon must be illusory even though the canals are real.
One of the most significant facts that came out in the early observations was the evident connection between the appearance of the canals and the seasonal changes on Mars.

It was about the time of the spring equinox, when the white polar caps had begun to melt, that Schiaparelli first noticed the phenomenon of duplication.

As the season advanced the doubling of the canals increased in frequency and the lines became more distinct.