of Percival Lowell, who saw the planet as a formerly Earth-like world now becoming inhospitable to life because of its advanced age. According to the Barsoomians themselves, Mars was a lush world with global oceans just one million years before the present day. As the oceans evaporated and the atmosphere thinned, the planet devolved into partial barbarism. Living on a dying planet, with dwindling resources, the inhabitants of Barsoom have become hardened and warlike, constantly fighting one another to survive. Barsoomians distribute scarce water via a worldwide system of canals, controlled by quarreling city-states. The thinning Martian atmosphere is artificially replenished by an "atmosphere plant" on which all life on the planet depends. The days are warm and the nights are cold, and climate varies little across the planet, except at the poles. Scientific background In 1895 Percival Lowell published a book entitled Mars which speculated about an arid, dying landscape, whose inhabitants had been forced to build canals thousands of miles long to bring water from the polar caps to irrigate the remaining arable land. Lowell built upon ideas introduced by Italian astronomer, Giovanni Schiaparelli, who in 1877, observed geological features on Mars which he called canali (Italian for "channels"). This was mistranslated into the English as "canals" which, being artificial watercourses, fueled the belief that there was some sort of intelligent extraterrestrial life on the planet. In the early 20th century Lowell published two more books, further developing the concept of a dying Mars. Burroughs was aware of these theories and appears to have consciously followed them. However, Burroughs does not seem to have based his vision of Mars on precise reading of Lowell's theories, as there are a number of errors in his interpretation which suggest he may have got most of his information from reading newspaper articles and other popular accounts of Lowell's Mars. The ideas of canals with flowing water and an inhabited, if dying world, were later disproved by more accurate observation of the planet, and fly-bys and landings by Russian and American probes such as the two Viking missions which found a dead, frozen world where water could not exist in a liquid state. Antecedents The first science fiction to be set on Mars may be Across the Zodiac: The Story of a Wrecked Record, by Percy Greg, published in 1880. An 1897 novel by Kurd Lasswitz, Auf Zwei Planeten, dealt with benevolent