the Earth, 193-196

Mediterranean, tides in the, 537

Mercury, ancient study of, 6;
antiquity of its discovery, 155-157;
atmosphere of, 166;
attraction on comets of, 347;
climate of, 163;
comparative proximity to the Earth of, 111;
composition of, 160;
crescent-shaped, 160;
density of, 558;
diameter of, 558;
distance from the Sun of, 151, 558;
habitability of, 163;
movement of, 160, 161;
its elliptic form, 139, 161;
orbit of, 114;
period of revolution of, 161;
periodic appearances of, 158;
periodic time of, 558;
perturbations of, 350;
a planet or "wanderer," 111;
revolution of, 165;
rotation of, and Professor Schiaparelli, 165;
size of, compared with other planets, 116;
surface of, 162;
transit of, 152;
transit of, and Gassendi's observations, 164;
transit of, predicted by Kepler, 163;
velocity of, 162;
weight of, 166, 349

Meridian circle, 22, 24

Messier's Catalogue of Stars, 529

Meteors (_see_ Stars, shooting)

Meteorites, 391;
Alban Mount, 393;
ancient accounts, 392, 393;
Benares, 392;
Butsura, 397;
Chaco, 398;
characteristics of, 397;
Chladni's account of discovery in Siberia, 392;
composition of, 397-399;
Ensisheim (1492), 393;
Hindoo account of, 391;
L'Aigle, 392;
not connected with comets, 400;
not connected with star showers, 400;
Orgueil, 399;
origin, 400-408;
Ovifak, 407;
Rowton, 395-396;
Wold Cottage, 392

Micrometer, 86

Milky Way, 462-3, 474-6

Mimas, 559

Minor planets, 229-244

Mira Ceti, 430, 482

Mizar, 438, 486

Moment of momentum, the, 552-554

Month of one day, 547

Moon, The, absence of air on, 85, 99;
absence of heat on, 95;
agent in causing the tides, 70, 535-537;
ancient discoveries respecting, 5;
apparent size of, 73;
attraction to the Earth of, 75;
brightness of, as compared with that of the Sun, 71;
changes during the month of, 71, 74;
chart of surface of, 81;
craters on, 83, 84, 87-98, 514;
density of, 558;
diameter of, 558;
distance from the Earth of, 73, 75, 568;
eclipses of, 6, 77-80;
illustration of the law of gravitation, 96, 131, 133;
landscapes on, 98;
life impossible on, 99;
measuring heights of mountains, etc., of, 85, 86;
micrometer, 86; motion of, 75;
mountains on, 83, 85, 88, 89, 91, 93;
phases of, 71, 76;
plane of orbit of, 310, 500, 501;
poets and artists and, 72;
pole, 500;
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