Sky and Telescope - July 2018 - 31
today in English as Camille Flammarion's the Planet Mars) and
his popular magazine L'Astronomie, covering the oppositions
of 1887 to 1894, to fully appreciate just how widespread the
notion of canals and Mars's habitability was.
It all began with the very favorable Martian opposition of
1877, during which famed Italian astronomer Giovanni Schiaparelli set out to accurately map the planet's albedo features.
Working with an 8.6-inch Merz refractor at Brera Observatory
in Milan, Schiaparelli had earned distinction by establishing a
link between Comet 109P/Swift-Tuttle and the Perseid meteor
shower, discovering the asteroid Hesperia, and conducting
excellent double-star studies. He was not the ﬁrst to show linear features on the planet, however, nor to call them "canali"
(meaning channels). Italian astronomer Father Angelo Secchi
ﬁrst used that term in association with Mars in 1858.
Schiaparelli was the ﬁrst, though, to map an extensive
network of seemingly linear features crisscrossing the planet
throughout the apparition of 1877. It was widely assumed at
the time that some of the dark features were seas and lakes
while the polar caps were composed of water ice, and the
planet's atmosphere was far denser and more Earthlike than
in actuality. That, coupled with seasonal changes in the polar
caps and darkening of many albedo features, was taken as
evidence as early as the 1860s that Mars was geologically
quite similar to Earth and probably harbored intelligent life.
Elias Colbert, director of Dearborn Observatory near Chicago, exempliﬁed this view when he wrote, in 1871, "Mars
is, therefore, adapted as a residence for rational beings, like
ourselves; and that the Martians had likely attained a higher
state of mental development than we have . . ."
This conviction was also in keeping with the popular
doctrine of "the plurality of worlds" during the 18th and
19th centuries, which asserted that most celestial bodies are
inhabited. This idea was based on teleological rather than
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