Liftwood trees grow in a certain region of the Martian highlands, and nowhere else. Attempts to grow the trees in greenhouses have all failed to date, as have laboratory attempts to synthesize the specific protein that concentrates in its sap. This complex organic compound has been found to produce so-called “contragravitational effects”—in layman’s terms, anti-gravity. In practice, ships constructed from liftwood soar through the skies as lightly as balloons or zeppelins.
This has led to a renaissance of flight, brought on by Edison’s discovery of liftwood in 1870 (yet another development of his and Jack Armstrong’s fateful expedition). Since then, aeronautical research has resulted in countless advances. Zeppelin-Daimler airships, held aloft by hydrogen and utilizing highly safe and efficient internal combustion engines, are in widespread use in Europe, on Earth. On Mars, the kites of the Martians ply the orange skies much as sailing ships did on Earth’s sea of old. With liftwood so scarce, piracy is common among the Martian flyers, and conflicts over liftwood supplies are constant.