Part 3 — INDEX

Aberration, 49 Absorption of energy, 46 Acceleration, 64, 67, 70 Action at a distance, 48 Addition of velocities, 16, 38 Adjacent points, 89 Aether, 52 —drift, 52, 53 Arbitrary substitutions, 98 Astronomy, 7, 102 Astronomical day, 11 Axioms, 2, 123 truth of, 2 Bachem, 131 Basis of theory, 44 "Being," 66, 108 β-rays, 50 Biology, 124 Cartesian system of co-ordinates, 7, 84, 122 Cathode rays, 50 Celestial mechanics, 105 Centrifugal force, 80, 130 Chest, 66 Classical mechanics, 9, 13, 14, 16, 30, 44, 71, 102, 103, 124 —truth of, 13 Clocks, 10, 23, 80, 81, 94, 95, 98-100, 102, 113, 129 —rate of, 129 Conception of mass, 45 —position, 6 Conservation of energy, 45, 101 —impulse, 101 —mass, 45, 47 Continuity, 95 Continuum, 55, 83 —two-dimensional, 94 —three-dimensional, 57 —four-dimensional, 89, 91, 92, 94, 122 —space-time, 78, 91-96 —Euclidean, 84, 86, 88, 92 —non-Euclidean, 86, 90 Co-ordinate differences, 92 —differentials, 92 —planes, 32 Cottingham, 128 Counter-Point, 112 Co-variant, 43 Crommelin, 128 Curvature of light-rays, 104, 127 space, 127 Curvilinear motion, 74 Cyanogen bands, 131 Darwinian theory, 124 Davidson, 128 Deductive thought, 123 Derivation of laws, 44 De Sitter, 17 Displacement of spectral lines, 104, 129 Distance (line-interval), 3, 5, 8, 28, 29, 84, 88, 109 —physical interpretation of, 5 —relativity of, 28 Doppler principle, 50 Double stars, 17 Eclipse of star, 17 Eddington, 104, 128 Electricity, 76 Electrodynamics, 13, 19, 41, 44, 76 Electromagnetic theory, 49 —waves, 63 Electron, 44, 50 —electrical masses of, 51 Electrostatics, 76 Elliptical space, 112 Empirical laws, 123 Encounter (space-time coincidence), 95 Equivalent, 14 Euclidean geometry, 1, 2, 57, 82, 86, 88, 108, 109, 113, 122 —propositions of, 3, 8 Euclidean space, 57, 86, 122 Evershed, 131 Experience, 49, 60 Faraday, 48, 63 FitzGerald, 53 Fixed stars, 11 Fizeau, 39, 49, 51 —experiment of, 39 Frequency of atom, 131 Galilei, 11 —transformation, 33, 36, 38, 42, 52 Galileian system of co-ordinates, 11, 13, 14, 46, 79, 91, 98, 100 Gauss, 86, 87, 90 Gaussian co-ordinates, 88-90, 94, 96-100 General theory of relativity, 59-104, 97 Geometrical ideas, 2, 3 —propositions, 1 ——truth of, 2-4 Gravitation, 64, 69, 78, 102 Gravitational field, 64, 67, 74, 77, 93, 98, 100, 101, 113 ——potential of, 130, 131 Gravitational mass, 65, 68, 102 Grebe, 131 Group-density of stars, 106 Helmholtz, 108 Heuristic value of relativity, 42 Induction, 123 Inertia, 65 Inertial mass, 47, 65, 69, 101, 102 Instantaneous photograph (snapshot), 117 Intensity of gravitational field, 106 Intuition, 123 Ions, 44 Kepler, 125 Kinetic energy, 45, 101 Lattice, 108 Law of inertia, 11, 61, 62, 98 Laws of Galilei-Newton, 13 —of Nature, 60, 71, 99 Leverrier, 103, 126 Light-signal, 33, 115, 118 Light-stimulus, 33 Limiting velocity (), 36, 37 Lines of force, 106 Lorentz, H. A., 19, 41, 44, 49, 50-53 —transformation, 33, 39, 42, 91, 97, 98, 115, 118, 119, 121 ——(generalised), 120 Mach, E., 72 Magnetic field, 63 Manifold (see Continuum) Mass of heavenly bodies, 132 Matter, 101 Maxwell, 41, 44, 48-50, 52 —fundamental equations, 46, 77 Measurement of length, 85 Measuring-rod, 5, 6, 28, 80, 81, 94, 100, 102, 111, 113, 117 Mercury, 103, 126 —orbit of, 103, 126 Michelson, 52-54 Minkowski, 55-57, 91, 122 Morley, 53, 54 Motion, 14, 60 —of heavenly bodies, 13, 15, 44, 102, 113 Newcomb, 126 Newton, 11, 72, 102, 105, 125 Newton's constant of, gravitation, 131 —law of gravitation, 48, 80, 106, 124 —law of motion, 64 Non-Euclidean geometry, 108 Non-Galileian reference-bodies, 98 Non-uniform motion, 62 Optics, 13, 19, 44 Organ-pipe, note of, 14 Parabola, 9, 10 Path-curve, 10 Perihelion of Mercury, 124-126 Physics, 7 —of measurement, 7 Place specification, 5, 6 Plane, 1, 108, 109 Poincaré, 108 Point, 1 Point-mass, energy of, 45 Position, 9 Principle of relativity, 13-15, 19, 20, 60 Processes of Nature, 42 Propagation of light, 17, 19, 2, 32, 91, 119 ——in liquid, 40 ——in gravitational fields, 75 Quasi-Euclidean universe, 114 Quasi-spherical universe, 114 Radiation, 46 Radioactive substances, 50 Reference-body, 5, 7, 9-11, 18, 23, 25, 26, 37, 60 ——rotating, 79 Reference-mollusk, 99-101 Relative position, 3 —velocity, 117 Rest, 14 Riemann, 86, 108, 111 Rotation, 81, 122 Schwarzschild, 131 Seconds-clock, 36 Seeliger, 105, 106 Simultaneity, 22, 24-26, 81 —relativity of, 26 Size-relations, 90 Solar eclipse, 75, 127, 128 Space, 9, 52, 55, 105 —conception of, 19 Space co-ordinates, 55, 81, 99 Space-interval, 30, 56 —point, 99 —two-dimensional, 108 —three-dimensional, 122 Special theory of relativity, 1-57, 20 Spherical surface, 109 —space, 111, 112 St. John, 131 Stellar universe, 106 —photographs, 128 Straight line, 1-3, 9, 10, 82, 88, 109 System of co-ordinates, 5, 10, 11 Terrestrial space, 15 Theory, 123 —truth of, 124 Three-dimensional, 55 Time, conception of, 19, 52, 105 —co-ordinate, 55, 99 —in Physics, 21, 98, 122 —of an event, 24, 26 Time-interval, 30, 56 Trajectory, 10 "Truth," 2 Uniform translation, 12, 59 Universe (World) structure of, 108, 113 —circumference of, 111 Universe elliptical, 112, 114 —Euclidean, 109, 111 —space expanse (radius) of, 114 —spherical, 111, 114 Value of , 82, 110 Velocity of light, 10, 17, 18, 76, 118 Venus, 126 Weight (heaviness), 65 World, 55, 56, 109, 122 World-point, 122 —radius, 112 —sphere, 110, 111 Zeeman, 41

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