CHAPTER V.
TEMPERATURE OF MARS--MR. LOWELL'S ESTIMATE, --Problem of terrestrial temperature --Ice under recent lava --Tropical oceans ice-cold at bottom --Earth's surface-heat all from the sun --Absolute zero of temperature --Complex problem of planetary temperatures --Mr. Lowell's investigation of the problem --Abstract of Mr. Lowell's paper --Critical remarks on Mr. Lowell's paper.