CHAPTER VI.
A NEW ESTIMATE OF THE TEMPERATURE OF MARS, -- Langley's determination of lunar heat -- Rapid loss of heat by radiation on the earth -- Rapid loss of heat on moon during eclipse -- Sir George Darwin's theory of the moon's origin -- Very's researches on the moon's temperature -- Application of these results to the case of Mars -- Cause of great difference of temperatures of earth and moon -- Special features of Mars influencing its temperature -- Further criticism of Mr.Lowell's article -- Very low temperature of arctic regions on Mars..