SUBJECT INDEX 



373 



Radon, coefficient of distribution, 75 



extraction plant, 77 



freezing point, 75 



half-life, 60 



implants, 78, 80 



medical uses, 75, 80 



solubility, 75 



sources, 76 



strength, 79 



transient activity, 76 



use of, 75 

 Radon seeds, 78 

 Ramsden eyepiece, 329 

 Range of electrons, in air, 41 



in water, 41 

 Ranvier nodes, 214 

 Rayleigh's resolution criterion, 316 

 Reboul's hydrodynamic cochlear theory, 



303 

 Refraction, index of, 318, 325 

 Refractory period, 222 



absolute, 223 



relatively, 223 

 Reissner membrane, 282, 283, 284 

 Resolution limit, 314, 316 

 Resolving power, of aural membrane, 

 306 



of electron microscope, 332 



of eye, 311 



of microscope, 316 



of photographic emulsion, 350 

 Retina, cones, 123, 124 



fovea centralis, 121, 123 



macula lutea, 121, 123, 124 



neurons in, 122 



ora serrata, 121 



rods, 123, 124 



structure of, 122 



vitamin A content, 159 

 Retinal sensitivity to red light, 119 

 Rheobase, 233, 234 

 Rickets, 133, 163 

 Rod vision, 117 

 Roentgen unit (r), biological, 84, 86 



denned, 42, 44 



effective, 84 



meters, 45, 46 



per minute, 47 



per second, 44 

 Round window, 271, 283 



Sap, composition of, 208 



Saturation curve of ionization, 40 



Saturation voltage, 40 



Scala media, 282, 283, 284 



Scala tympani, 282, 284 



Scala vestibuli, 282-285 



Scattering, Compton, 14, 23, 26, 35, 39 



mass, 20 



physical influences, 21 



primary, 14 

 Scattering coefficients, table of, 21 

 Schlemm, canal of, 103, 106 

 Sea water, composition of, 208 

 Serum, albumin, absorption, 146 

 Serum pseudoglobulin, absorption, 146 

 Semi-permeable membrane, cells, 188, 

 189 



human skin, 189 



living, 209 

 Sensation unit, audible, 291 

 Sensitivity of organisms to ultraviolet 



radiation, 162 

 Sigmoid, aural, operating curve, 274 

 Simple harmonic motion, 254 



displacement, 255 



energy, 258 



velocity, 257 

 Skin, pigment, 137 

 Snellen, chart, 127 

 Snell's law, 333 

 Soap-bubble pressure, 173 

 Sound, 253 

 Space charge, 3 



Spectral transmission, " Federal Master 

 Specifications," 120 



of glass, 119 



of goggles, 120 



of water, 119 

 Spectrophotometry, 147 

 Speech, intensity of, 291 



power level, 291 

 Spekker photometer, 148 

 Spherical aberration of eye, 110 

 Stalagmometer, 184 

 Stapedius tensor, 277, 278, 281 

 Stapes, 268, 271, 277 



arches, 278 



capitulum, 277, 278 



crura, 278 



footplate, 277, 278, 283 



