CHAPTER VI.

THE GENERAL ASPECT OF THE LUNAR SURFACE. 51 Pre-Telescopic Ideas—Human Countenance—Other supposed Resemblances—Portrait of Full Moon—Permanence of Features—Rotation of Moon—Solar Period and Solar Day on Moon—Libration—Diurnal—In Latitude—In Longitude—Visible and Invisible Hemispheres—Telescopic Scrutiny—Galileo’s Views—Features Visible with Low Power—Low Powers on small and large Telescopes—Salient Features—Craters—Plains—Bright Streaks—Mountains—Higher Telescopic Powers—Detail Scrutiny of Features therewith—Discussion of High Powers—Education of Eye—Highest practicable Power—Size of smallest Visible Objects