miles); even closer ones seem to be produced, but the telescope is not
powerful enough to distinguish them with certainty. Their tint appears
to be a quite deep reddish brown. The parallelism is sometimes
rigorously exact. 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. In the meantime the polar caps were becoming
smaller. Broadly speaking, Schiaparelli's observation showed that the
doubling of the canals occurred principally a little after the spring
equinox and a little before the autumn equinox; that the phenomenon
disappeared in large part at the epoch of the winter solstice, and
disappeared altogether at the epoch of the summer solstice. Moreover, he