Part 63

Sensations, analysed, 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, rôle of, in vision, 81.

Shakespeare, 278.

Sharps, reversed into flats, 101.

Shell, 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.