A Princess of Mars 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
The Case for Mars to silver which have not been subjected to millennia of human scavenging and may be sold on Earth for profit. Secondly, the concentration of deuterium – a possible fuel for commercial nuclear fusion – is five times greater on Mars. Humans emigrating to Mars thus have an assured industry and the planet will be a magnet for settlers as wage costs will be high. The book asserts that “the labor shortage that will prevail on Mars will drive Martian civilization toward both technological and social advances.” While detailing the exploration and colonization, "The Case for Mars" also addresses a number