Part 30

Sinus Medii, 103.

Sinus Roris, 159.

Size of moon, 8.

Sky as seen from moon, 29.

Snow, can it exist on the moon? 69.

Snow, non-existence of, on moon, 69.

South polar region of moon, 77.

South pole of moon, 106.

Stadius, 218.

Stöfler, 75. row of rings near, 204.

“Straight wall,” 187.

Strait between Apennines and Caucasus, 234.

Sulpicius Gallus, 222.

Sunrise, slow progress of, on moon, 94.

Sunshine, effects of, when vertical on moon, 100.

Surface of moon, nature of, 9. size of, 9.

Synodic revolution of, 11-12.

Tacitus, 200.

Telescopic power, limits of, 120.

Teneriffe Mountains, 231.

“Terminator,” meaning of, 63.

Theætetus, 225.

Theophilus, 71, 138, 198, 206. crater pits near, 211. grandeur of appearance of, when highly magnified, 207. great mountain fold near, 207-208. what would be seen from wall of, near sunset, 208.

Tidal attraction, forcing moon away in reaction of, 6.

“Tidal friction,” 20.

Tides, causing of, by moon and sun, 21. effect of earth’s rotation on, 25. service rendered by, 22. simultaneous occurrence of, on opposite sides of earth, 23. when highest, 21. when lowest, 22.

Twilight, why none on moon, 64.

Tycho, 10, 98, 106, 146, 191. longest ray of, 93, 221. ray system of, 124. rays of, 99. theory of Nasmyth, 124-125. theory of Pickering, 126.