Momentum, 184.

Monocular vision, 98.

Monotheism of the Christians and Jews, 187.

Montagues and Capulets, 87.

Moon, eclipse of, 219; lightness of bodies on, 4; the study of the, 90, 284.

Moreau, 307.

Mosaic of thought, 192.

Motion, a perpetual, 181; quant.i.ty of, 184; the Eleatics on, 158; Wundt on, 158; the Herbartians on, 158.

Motions, natural and violent, 226; their familiar character, 157.

Mountains of the earth, would crumble if very large, 3; weight of bodies on, 112.

Mozart, 44, 279.

MAller, Johann, 291.

Multiplication-table, 195.

Multiplier, 132.

Music, band of, its tempo accelerated and r.e.t.a.r.ded, 53; the principle of repet.i.tion in, 99 et seq.; its notation, mathematically ill.u.s.trated, 103-104.

Musical notes, reversion of, 101 et seq.; their economy, 192.

Musical scale, a species of one-dimensional s.p.a.ce, 105.

Mystery, in physics, 222; science can dispense with, 189.

Mysticism, numerical, 33; in the principle of energy, 184.

Mythology, the mechanical, of philosophy, 207.

Nagel, von, 364.

Nansen, 296.

Napoleon, picture representing the tomb of, 36.

Nations, intercourse and ideas of, 336-337.

Natural constants, 193.

Natural law, a, not contained in the conformity of the energies, 175.

Natural laws, abridged descriptions, 193; likened to type, 193.

Natural motions, 225.

Natural selection in scientific theories, 63, 218.

Nature, experience the well-spring of all knowledge of, 181; fashions of, 64; first knowledge of, instinctive, 189; general interconnexion of, 182; has many sides, 217; her forces compared to purposes, 14-15; likened to a good man of business, 15; the economy of her actions, 15; how she appears to other animals, 83 et seq.; inquiry of, viewed as a torture, 48-49; view of, as something designedly concealed from man, 49; like a covetous tailor, 9-10; magic powers of, 189; our view of, modified by binocular vision, 82; the experimental method a questioning of, 48.

Negro hamlet, the science of a, 237.

Neptune, prediction and discovery of the planet, 29.

New views, 296 et seq.

Newton, describes polarisation, 242; expresses his wealth of thought in Latin, 341; his discovery of gravitation, 225 et seq.; his solution of dispersion, 362; his principle of the equality of pressure and counterpressure, 191; his view of light, 227-228; on absolute time, 204; selections from his works for use in instruction, 368; also 270, 274, 279, 285, 289.

n.o.bility, they displace Latin, 342.

Notation, musical, mathematically ill.u.s.trated, 103-104.

Numbers, economy of, 195; their connexion with consonance, 32.

Numerical mysticism, 33.

Nursery, the questions of the, 199.

Observation, 310.

Observation, in science, 261.

Ocean-stream, 272.

Oettingen, Von, 103.

Ohm, on electric currents, 249.

Ohm, the word, 343.

Oil, alcohol, water, and, employed in Plateau's experiments, 4; free ma.s.s of, a.s.sumes the shape of a sphere, 12; geometrical figures of, 5 et seq.

One-eyed people, vision of, 98.

Ophthalmoscope, 18.

Optic nerves, 96.

Optimism and pessimism, 234.

Order of physics, 197.

Organ, bellows of an, 135.

Organic nature, results of Darwin's studies of, 215 et seq. See Adaptation and Heredity.

Oriental world of fables, 273.

Orientation, sensations of, 282 et seq.

Oscillation, centre of, 147 et seq.

Ostwald, 172.

Otoliths, 301 et seq.

Overtones, 28, 40, 349.

Ozone, SchAbein's discovery of, 271.

Painted things, the difference between real and, 68.

Palestrina, 44.

Parameter, 257.

Partial tones, 390.

Particles, smallest, 104.

Pascheles, Dr. W., 285.

Paulsen, 338, 340, 373.

Pearls of life, strung on the individual as on a thread, 234-235.

Pencil surpa.s.ses the mathematician in intelligence, 196.

Pendulum, motion of a, 144 et seq., increased motion of, due to slight impulses, 21; electrical, 110.

Percepts, of like form, 390.

Periodical, changes, 181; series, 256.

Permanent, changes, 181, 199; elements of the world, 194.

Perpetual motion, a, 181; defined, 139; impossibility of, 139 et seq.; the principle of the, excluded, 140 et seq.; excluded from general physics, 162.

Personality, its nature, 234-235.

Perspective, 76 et seq.; contraction of, 74 et seq.; distortion of, 77.

Pessimism and optimism, 234.

Pharaohs, 85.

Phenomenology, a universal physical, 250.

Philistine, modes of thought of, 223.

Philology, comparison in, 239.

Philosopher, an ancient, on the moral and physical sciences, 89.

Philosophy, its character at all times, 186; mechanical, 155 et seq., 188, 207, 259 et seq.

Phonetic alphabets, their economy, 192.

Photography, by the electric spark, 318 et seq.

Photography of projectiles, 309-337.

Photography, stupendous advances of, 74.

Physical, concepts, fetishism in our, 187; ideas and principles, their nature, 204; inquiry, the economical nature of, 186; research, object of 207, 209.

Physical phenomena, as mechanical phenomena, 182; relations between, 205.

Physico-mechanical view of the world, 155, 187, 188, 207 et seq.

Physics, compared to a well-kept household, 197; economical experience, 197; the principles of, descriptive, 199; the methods of, 209; its method characterised, 211; comparison in, 239; the facts of, qualitatively h.o.m.ogeneous, 255; how it began, 37; helped by psychology, 104; study of its own character, 189; the goal of, 207, 209.

Physiological psychology, its methods, 211 et seq.

Physiology, its scope, 212.

Piano, its mirrored counterpart, 100 et seq.; used to ill.u.s.trate the facts of sympathetic vibration, 25 et seq.

Piano-player, a speaker compared to, 192.

Picture, physical, a, 110.

Pike, learns by experience, 267.

Pillars of Corti, 19.

Places, heavy bodies seek their, 224 et seq.

Planetary system, origin of, ill.u.s.trated, 5.