Mariner's Compass, iv, 253-4, vii, 365; invention and improvements, vi, 29, 41-2 Mariotte, Edme, xvi, 110, 111; law of, iv, 140 Markhor, xii, 325 Marmosets, xii, 376 Marmots, xii, 294-5 Marne, Battle of, defence of "Grande Couronne", xiv, 90; soldiers asleep on retreat, xi, 286-7 Marne River, topographical features, xiv, 89 Marquette, Père, xiv, 192 Marriage, xv, 273-95, 364 Mars, (planet), ii, 227-34; atmosphere, 228-32, 247; canals, 235-41, 248; distance, 235-6; Kepler's studies, 50; life on, 228-32, 237-8, 247-8; "lucid" planet, 264; motions and orbits, 50, 162, 163; photographic study, 131, 132; rotation period, 59, 377; satellites, 241, 110; size, 162, 163; surface study, 238-9; Tycho Brahe's studies, 49; weight, 76, 77-8 Marshes, draining of, by trees, xiv, 379; malaria and, x, 154, 300 Marsh Gas, iii, 345, 354, viii, 51; as ignis fatuus, i, 347, 348 (see also Methane) Marshmallow, family, xiii, 200 Marsupials, xii, 274-81; evolution of, 271 Martens, xii, 350, 351 Martensite, viii, 274 Martha's Vineyard, waves action, iii, 56 Martin, Prof. E. G., author PHYSIOLOGY Vol. ix Maryland, former volcanoes, xiv, 318; oyster industry, xii, 61 Maskelyne, astronomer, xvi, 124; mountain-weighing, ii, 68-9 Mass, defined, iv, 35, xvi, 130; density and, iv, 110; measured by beam balance, 102; momentum in relation to, 62-3; motion in relation to, 60-1, 63-5, 72, 78; standard units of, 46, 69, xvi, 130; weight and, iv, 35, 110, xvi, 130 Massage, ancient Chinese, x, 13; effect on lymphatics, ix, 223 Massasauga, xii, 235 Mastoiditis, ix, 61-2 Matches, friction and safety, viii, 88; invention of, xv, 232 Materialism, xi, 13-14; in mediæval philosophy, x, 35 Materia Medica, Mesue's work on, x, 32; 17th century improvements, xvi, 109 Mathematical Astronomy, ii, 15, 113-14; culmination of, 15, 71-2; spectroscopic methods in, 119-24 Mathematical Calculations, development of, xv, 181-4, xvi, 61 Mathematical Machines, v, 326-7 Mathematics, coordinates used in, iv, 16; Golden Age, ii, 15; history of development, xvi, 54, 60-3, 68, 71-2, 79-81, 88-90, 92, 94-5, 103-5, 113-14, 118-19, 125; practice of challenges in, iv, 89 Mather, Cotton, on disease, x, 380; on inoculation, 101 Mating Instinct, xiii, 116 Mato Tepee, xiv, 129-30