Magnetic Axis, of earth, iv, 250 Magnetic Blowout, vii, 37, 39 Magnetic Circuits, vii, 364; force of, vi, 93 Magnetic Disturbances, accompanying aurora, i, 161; due to moon, ii, 201; sun-spots and, 176, 186 Magnetic Equator, iv, 246 Magnetic Fields, iv, 251, vi, 31, vii, 368; concentration of, vi, 91-2; distortion, 43-4; electromotive force created by, 50-3, 54; electron theory, 128; generator and motor actions in, 218-19; of atoms, 117; of earth, iv, 253, vi, 39, 40; of electric currents, iv, 274-5, 277, 279 (fig.), vi, 19-20, 88-91; of sun, ii, 177-9; spectra of vapors in, 178; strength or intensity, iv, 252, vii, 368, 370 Magnetic Force, vii, 369 Magnetic Leakage, vii, 371 Magnetic Meridians, iv, 246 Magnetic Needle, iv, 243-4; dip or inclination of, 245-6; earth's action on, 248; electric current effects on, 273-4, 275-6, 278-9 Magnetic Permeability, vii, 372 Magnetic Poles, vii, 374; force of attraction between, iv, 249 Magnetic Poles (of earth), iv, 246, 248, vi, 29-30; aurora in relation to, i, 159-60 Magnetic Saturation, vii, 372 Magnetic Screens, vi, 32 (fig.) Magnetic Storms, vi, 40 Magnetism, iv, 242-55, vi, 27-45; daily application, xvi, 19, 30; effects on body, vii, 246, 247; electricity and, vi, 12, 19-20, 27-8, 86, iv, 256, 276; electron theory, vii, 371; energy in, iv, 82; force of, how measured, 249; history of, 52-5, vi, 9-26, xvi, 109, 122; law of attraction and repulsion, vi, 18, 42-3, 286-7; of direct and alternating currents, 155-6; lines of force (see Lines of Force); of earth, iv, 248-50, 252, vi, 29-30, 39-40; of earth, connection with internal iron, xiv, 11; of rotating bodies, ii, 178, vi, 21; residual, vi, 191, vii, 372; science of power, xvi, 36-7; term as used, vii, 372; universal presence, vi, 40 (see also Electromagnetism, Magnetic Fields, Magnets) Magnetite, iii, 333-4, viii, 156; ores in Adirondacks, iii, 359; properties of, iv, 242 Magnetization, iv, 242; aided by striking, 253; by electric currents, 286-8, vi, 30, 50; by induction, iv, 243, 253; by lightning, i, 152-3; by loadstone, vi, 29; internal effects, 36-7; of iron structures, iv, 253; molecular effects, 245, 253; processes of, vi, 44-5; test, 43 Magneto Generators, vi, 215-16 Magnetomotive Force, vi, 92-3 Magnetos, automobile, vii, 140-41