274 
THE QUANTUM 
Printed in Great Britain by Butler & Tanner Ltd., Frome and London 
Selection principles, 64, 80 
Sequence, spectroscopic, 50 
Sharp series, 51 
Single line spectrum, no 
Space-lattice, 12, 121 
Spatial quantization, 13, 83-90 
Specific heat, 10, 11 
Spectral series, 8, 47, 147 
terms, 50, 212 
complex, 78-82 
Spectrum, hydrogen, 48 
rotation, 231 
sodium, 50, 62, 211 
Spectroscopy, 47 
Spectroscopic units, 47 
Spinning electron, 13, 168, 214, 215, 
216-23 
Splitting factor, 99, 213 
Stark effect, 10, 67, 180, 238 
Static models, 14, 121-33, 249-50 
Stationary states, 8,11,18, 22, 25, 52 
Statistical methods, 240-2 
weight, 221 
Steady states (see Stationary states) 
Stripped atoms, 59, 215 
Susceptibility, magnetic, 89, 91-6 
Terms, spectral, 50, 212 
Thermodynamics, 12, 241 
Threshold frequency, 5 
Triatomic hydrogen, 131, 132 
Tubes of force (see Faraday tubes) 
Ultimate rational units, 174 
Undulatory mechanics, 90, 203, 
233-9, 250 
Undulatory theory of light, 6, 185, 
195, 202 
Unit of length, 47, 54 
magnetic tube, 44 
Unitary theory of light (see Light 
quanta) 
Valency, 79, 102-4, 123, 212 
Velocity, group, 201 
Velocity in orbit, 56, 178 
of electron, 5, 201-2 
of light, 47, 56,176, 178, 201, 2x7, 
257 
Virtual radiation field, 198 
Wave equation, 236 
Wave function rp, 236, 238, 251 
Wave-length, 3, 47 
Wave-number, 48 
Wave theory of light, 6, 185, 195, 
202 
of matter, 201, 203 
Weber elements, 32, 95 
Weiss magneton, 35, 36, 96-8, 102 
Wien’s radiation formula, 203, 258 
Winkelkoordinaten, 25 
World, four dimensional, 150, 154 
World-line, 154, 173 
X-rays, 6, 9, 182, 197, 231, 245 
X-ray spectra, 70, 72, 99 
X-unit, 47 
Zeeman effect, 10, 67, 181, 199, 
204-15, 220 
Zero-point energy, 230