Is Mars Habitable? A Critical Examination of Professor Percival Lowell's Book "Mars and Its Canals," with an Alternative Explanation

Telescopic lines on Mars become a test of scientific reasoning in Alfred Russel Wallace's examination of Percival Lowell's claims. Lowell interprets the markings as canals built by intelligent inhabitants. Wallace asks whether the planet could supply the water, air and warmth that such a population would need. His preface, dated October 1907, explains how a planned review grew into a book as the physical questions demanded closer attention.

The chapters combine accounts of early observations with arguments about atmospheric pressure, heat loss and the polar caps. Wallace compares Mars with the Earth and Moon, challenges Lowell's temperature calculations and proposes a geological explanation for the apparent canals and dark spots. A note by physicist J. H. Poynting adds another criticism of the climate estimate. For readers interested in the history of astronomy, the book shows how observers could agree on visible markings yet dispute what those markings meant.