Schlierenmethode, 317.

SchAnbein's discovery of ozone, 271.

School-boy, copy-book of, 92.

Schoolmen, 214.

Schools, State-control of, 372 et seq.

Schopenhauer, 190.

Schultze, Max, 19.

Science, a miserly mercantile principle at its basis, 15; compared to a business, 16; viewed as a maximum or minimum problem, 16, footnote; its process not greatly different from the intellectual activity of ordinary life, 16, footnote; economy of its task, 16; relation of, to poetry, 30, 31, 351; the church of, 67; beginnings of, 189, 191; belief in the magical power of, 189; can dispense with mystery, 189; lavish extravagance of, 189; economy of the terminology of, 192; partly made up of the intelligence of others, 196; stripped of mystery, 197; its true power, 197; the economical schematism of, 206; the object of, 206; the tools of, 207; does not create facts, 211; of the future, 213; revolution in, dating from Galileo, 214 et seq.; the natural foe of the marvellous, 224; characterised, 227; growth of, 237; dramatic element in, 243; described, 251; its function, 253; cla.s.sification in, 255, 259 et seq.; the way of discovery in, 316. See also Physics.

Sciences, part.i.tion of the, 86; the barriers and relations between the 257-258; on instruction in the, 338-374.

Scientific, criticism, Socrates the father of, 1, 16; discoveries, their fate, 138; knowledge, involves description, 193; thought, transformation and adaptation in, 214-235; thought, advanced by new experiences, 223 et seq.; thought, the difficulty of, 366; terms, 342-343; founded on primitive acts of knowledge, 190.

Scientists, stories about their ignorance, 342.

Screw, the, 62.

Sea-sickness, 284.

Secret computation, Leibnitz's, 33.

Seek their places, bodies, 226.

Self-induction, coefficient of, 250, 252.

Self-observation, 211.

Self-preservation, our first knowledge derived from the economy of, 197; struggle for, among ideas, 228.

Semi-circular ca.n.a.ls, 290 et seq.

Sensation of rounding a railway curve, 286.

Sensations, a.n.a.lysed, 251; when similar, produce agreeable effects, 96; their character, 200; defined, 209; of orientation, 282 et seq.

Sense-elements, 179.

Senses, theory of, 104; the source of our knowledge of facts, 237.

Seventh, the troublesome, 46.

Shadow method, 313 et seq., 317 footnote.

Shadows, rAle of, in vision, 81.

Shakespeare, 278.

Sharps, reversed into flats, 101.

Sh.e.l.l, spherical, law of attraction for a, 124, footnote.

Shoemaker, inquirer compared to, 105-106.

Shooting, 309.

Shots, double report of, 229 et seq.

Similarity, 249.

Simony, 280.

Simplicity, a varying element in description, 254.

Sines, law of the, 193.

Sinking of heavy bodies, 222.

Sixth sense, 297.

Smith, R., on acoustics, 34, 381, 383.

Soap-films, Van der Mensbrugghe's experiment with, 11-12.

Soapsuds, films and figures of, 7.

Social potential, 15.

Socrates, the father of scientific criticism, 1, 16.

Sodium, 202.

Sodium-light, vibrations of, as a measure of time, 205.

Solidity, conception of, by the eye, 71 et seq.; spatial, photographs of, 73.

Solids, and liquids, their difference merely one of degree, 2.

Sonorous bodies, 24 et seq.

Soret, J. P., 89.

Sounds, symmetry of, 99 et seq.; generally, 22-47, 212.

Sound-waves rendered visible, 315 et seq.

Sources of the principle of energy, 179 et seq.

s.p.a.ce, 205; sensation of, 210.

Spark, electric, 117, 127, 132, 133, 190.

Spatial vision, 386.

Species, stability of, a theory, 216.

Specific energies, 291.

Specific heat, 166, 244.

Specific inductive capacity, 117.

Spectral a.n.a.lysis of sound, 27.

Spectrum, mental a.s.sociations of the, 190.

Speech, the instinct of, cultivated by languages, 354.

Spencer, 218, 222.

Sphere, a soft rotating, 2; the figure of least surface, 12; electrical capacity of, 123 et seq.

Spherical sh.e.l.l, law of attraction for 124, footnote.

Spiders, the eyes of, 67.

Spirits, as explanation of the world 186, 243.

Spiritualism, modern, 187.

Spooks, metaphysical, 222.

Squinting, 72.

Stability of our environment, 206.

Stallo, 336.

Stars, the fixed, 90.

State, benefits and evils of its control of the schools, 372 et seq.; the Church and, 88.

Statical electricity, 134.

Stationary currents, 249.

Statoliths, 303.

Steam-engine, 160, 265.

Steeple-jacks, 75.

Stereoscope, Wheatstone and Brewster's, 73.

Stevinus, on the inclined plane, 140; on hydrostatics, 141; on the equilibrium of systems, 142; discovers the principle of virtual velocities, 150; characterisation of his thought, 142; also 182, 187, 191.

Stone Age, 46, 321.

StArensen, 306.

Stove, primitive, 263.

Straight line, a, its symmetry, 98.

Straight, meaning of the word, 240.

Street, vista into a, 75.

Striae, in gla.s.s, 313.

Striate method, for detecting optical imperfections, 317.

Striking distance, 115, 127.

Strings, vibrations of, 249.

Struggle for existence among ideas, 217.

Substance, heat conceived as a, 177, 243 et seq.; electricity as a, 170; the source of our notion of, 199; rAle of the notion of, 203, 244 et seq.; energy conceived as a, 164, 185, 244 et seq.

Subst.i.tution-value of heat, 178, footnote.

Suetonius, 348.

Sulphur, specific inductive capacity of, 117.

Sun, human beings could not exist on, 3.

Swift, 84, 280.

Swimmer, AmpAre's, 207.

Symmetry, definition of, 92; figures of, 92 et seq.; plane of, 94; vertical and horizontal, 94; in music, 99 et seq.