Magnets, iv, 242-4; action of, 250-1, vi, 31-2; aging of, 45, vii, 159; attraction and repulsion of, iv, 242, 244, 245, 249, vi, 33, 42-3, (fig.); demagnetization methods, iv, 253, vii, 366; effect on compass, vi, 27, 42-3; electromotive force produced by, iv, 303; force, how measured, 249-50; heat and jarring effects, vi, 34-8, 117; internal constitution, 36-7; laminated, 34, 35 (fig.); lines of force, 33 (see also Lines of Force); lifting force of, iv, 289; making of, vi, 44-5 (see Magnetization); natural, iv, 242; penetrability, 250, vi, 31-2; permanent and temporary, iv, 243, vi, 30; poles of, iv, 242, 244-5, 253, 262, vi, 31, 42, 43; types, 30-1, vii, 372; uses, commercial and industrial, iv, 255, viii, 270 (see also Electromagnets) Magnifying Glass, iv, 343 Magnitude, illusions of, xi, 184-90 Magnitude of Stars, absolute (see Absolute Magnitude); catalogued by Hipparchus, ii, 31; classification by, 295-6, 297; conditions affecting, 322; determined by photoelectric methods, 328; different kinds, 296; different stages, 383, 384; spectral type in relation to, 309 Magnolias, antiquity, xiii, 324-5; development, 55; fertilization, 130-1; former distribution, xiv, 375; fossil ancestor, xiii, 318; index plants, i, 255; in landscaping, xiii, 271-2 Mahogany, from tropical forests, xiv, 383; in anacardiaceae family, xiii, 200 Maidenhair Tree, xiii, 315-16; in landscaping, 271-3 Mail-Order Business, in stormy weather, i, 264 Maine, coast of, iii, 37-8, 57, 235, xiv, 256, 257, 262-3; coast destruction, 46; dikes on coast, iii, 110, xiv, 108; harbors, 268; moose of, xii, 318 Mains, electric, vii, 373 Maize, history and uses, xiii, 211-13 Major Triad (music), iv, 206-7 Make-and-Break (electricity), iv, 382 Malachite, iii, 334, 360 Malaise, sensation of, ix, 91 Malaria, x, 153-9; campaign against, 173-4, 299-301; control of, in tropics, xiv, 356, 357; former idea of causes, x, 286; quinine and, xiii, 250-1 Malaspina Glacier, iii, 70 Malay Archipelago, bananas native to, xiii, 216; continental relationships, xiv, 274; crocodiles of, xii, 201; lemurs of, 374, 375; largest flower in, xiii, 363-4; parrots of, xii, 266; rain forests, xiv, 369 Malay Peninsula, beriberi in, x, 257; coco palm of, xv, 125; leaf butterfly of, xii, 117; rhinoceros of, 306; snakes of, 214, 218; tapirs of, 306; tin production, iii, 369 Malays, hair of, xv, 37; immunity to tuberculosis, 51; in tropics, xiv, 356; members of brown race, xv, 37 Malic Acid, viii, 222-3, 336 Malicious Animal Magnetism, xi, 311 Malleable Iron, v, 319 Malleability, viii, 126; in mineral identification, 202 Mallow Family, xiii, 200 Malmags, xii, 374