Page:Relativity (1931).djvu/186

166 De Sitter, 21

Displacement of spectral lines, 124, 155

Distance (line-interval), 3, 5, 8, 34, 35, 99, 104, 129

physical interpretation of, 5

relativity of, 34

Doppler principle, 59

Double stars, 21

Eclipse of star, 21

Eddington, 124, 154

Electricity, 90

Electrodynamics, 15, 24, 48, 52, 90

Electromagnetic theory, 58

waves, 75

Electron, 52, 60

electrical masses of, 60

Electrostatics, 90

Elliptical space, 133

Empirical laws, 148

Encounter (space-time coincidence), 113

Equivalent, 16

Euclidean geometry, 1, 2, 68, 97, 101, 104, 128, 120, 135, 147

propositions of, 3, 8

space 68, 102, 147

Evershed, 158

Experience, 59, 70

Faraday, 56, 74

FitzGerald, 63

Fixed stars, 12

Fizeau, 46, 58, 61

experiment of, 46

Frequency of atom, 157

Gallilei, 12

transformation, 40, 43, 45, 50, 61

Galileian system of co-ordinates, 13, 15, 17, 54, 93, 108, 116, 119

Gauss, 102, 103, 106

Gaussian co-ordinates, 103, 105, 112, 114–118

General theory of relativity, 69–124, 115

Geometrical ideas, 2, 3

propositions, 1

truth of, 2–4

Gravitation, 75, 82, 92, 121

Gravitational field, 75, 79, 87, 91, 111, 116, 119, 120, 136

potential of, 157

mass, 76, 81, 121

Grebe, 158

Group-density of stars, 126

Helmholtz, 128

Heuristic value of relativity, 50

Induction, 148, 149

Inertia, 77

Inertial mass, 55, 76, 81, 120, 121

Instantaneous photograph (snapshot), 141

Intensity of gravitational field, 127