CHAPTER VI

THE PLANET MARS 180

The controversy about the habitableness of Mars. Humidity on Mars. Early observations. The spectra of Mars and of the Moon compared. Investigations by Campbell and Marchand. The work of Lowell. Measurements by Slipher. Calculations by Very. The temperature on Mars according to these sources. Campbell’s expedition to Mount Whitney in California. Oxygen on Mars. The cold on Mars detrimental to anything but the lowest forms of life. Cause of different results by Slipher and Campbell. Very’s answer to Campbell’s criticism. New measurements by Slipher. Campbell’s new method of measurement of 1910. Christiansen calculates the temperature on Mars from intensity of the Sun’s radiation. The sun-constant. Average temperature of Mars about forty degrees Centigrade. Possibly low plant life around the poles during summer. The canals on Mars are probably fissures in the crust. The length of the canals compared with that of the fissures in Earth’s crust. The double canals on Mars compared with the parallel fissures in Calabria. Emanations along the fissures. The canals as affected by increasing cold or heat. The polar snow. Thawing of the canals. Travel of the water vapour independent of the topography. The desert sand on Mars. Clouds and mists. Highlands and mountains on Mars. Sand filling of the canals. The seas on Mars. The straightness and uniform breadth of the canals an illusion. Light and dark spots. “New” canals. The fancies of Lowell.