Part 36

Aristotle, 348, 296.

Art, development of, 28 et seq.

Artillery, practical, 334-335.

Artistic value of scientific descriptions, 254.

Arts, practical, 108.

Ascent, heights of, 143-151.

Asia, 234.

Assyrians, the art of, 79.

Astronomer, measures celestial by terrestrial distances, 136.

Astronomy, antecedent to psychology, 90; rigidity of its truths, 221.

Atomic theories, 104.

Atoms, 207.

Attention, the rôle of, in sensuous perception, 35 et seq.

Attraction, generally, 226; of liquid particles, 13-14; in electricity, 109 et seq.

Aubert, 298.

Audition. See Ear.

Austrian gymnasiums, 370, footnote.

Axioms, instinctive knowledge, 190.

Babbage, on the economy of machinery, 196.

Bach, 20.

Backwards, prophesying, 253.

Bacon, Lord, 48, 280.

Baer, C. E. von, 235.

Balance, electrical, 127, footnote; torsion, 109, 168.

Balloon, a hydrogen, 199.

Barbarism and civilisation, 335 et seq.

Bass-clef, 101.

Bass, fundamental, 44.