Part 44

Ellipse, equation of, 205; the word, 342.

Embryology, possible future state of, 257.

Energies, conformity in the deportment of, 171-175; differences of, 175.

Energy, a metrical notion, 178; conservation of, 137 et seq.; defined, 139; metaphysical establishment of the doctrine of, 183; kinetic, 177; potential, 128 et seq.; substantial conception of, 164, 185, 244 et seq.; conservation of, in electrical phenomena, 131 et seq.; limits of principle of, 175; principle of, in physics, 160-166; sources of principle of, 179, 181; thermal, 177; Thomas Young on, 173.

Energy-value of heat, 178, footnote.

Enlightenment, the, 188.

Entropy, a metrical notion, 178.

Environment, stability of our, 206.

Equations for obtaining facts, 180; between the elements of phenomena, 205.

Equilibrium, conditions of, in simple machines, 151; figures of liquid, 4 et seq.; general condition of, 15; in the State, 15.

Etymology, the word, misused for entomology, 316.

Euclid, on consonance and dissonance, 33; his geometry, 364.

Euler, on the causes of harmony, 34; impression of the mathematical processes on, 196; on the vibrations of strings, 249, 285, 376.

Euler and Hermann's principle, 149.

Euthyphron, questioned by Socrates, 1.

Evolute, the word, 342.

Evolution, theory of, as applied to ideas, 216 et seq.

Ewald, 298, 304.

Excluded perpetual motion, logical root of the principle of, 182.

Exner, S., 302, 305.

Experience, communication of, 191; our ready, 199; the principle of energy derived from, 179; the wellspring of all knowledge of nature, 181; incongruence between thought and, 206.

Experimental research, function of, 181.

Explanation, nature of, 194, 237, 362.

Eye, cannot analyse colors, 20; researches in the theory of the, 18 et seq.; loss of, as affecting vision, 98.

Eyes, purpose of, 66 et seq.; their structure symmetrical not identical, 96.

Face, human, inverted, 95.

Facts and ideas, necessary to science, 231.

Facts, description of, 108; agreement of, 180; relations of, 180; how represented, 206; reflected in imagination, 220 et seq.; the result of constructions, 253; a continuum of, 256 et seq.; equations for obtaining, 180.