INDEX 



Aberration 306 



of light 356 

 Absolute pitch 545 



temperature 246 

 Absorbing powers 374 

 Absorption and adsorption of 

 gases 51 



atmospheric 352 



of electric radiation 408 



of heat rays 401 



selective 394 



spectra 396 



spectra and chemical con- 

 stitution 404 



Acceleration, measurement 121 

 Accommodation of eye 486 

 Achromatic telescopes 308 

 Achromatism 306 



in interference 362 

 Acoustic attraction 512 



transparency 533 

 Acoustics of buildings 534 

 Actinometry (photographic) 



448 



Action at a distance 79 

 Addresses 30 

 After-images 501 

 Air thermometers 155 

 Air-waves, illustrating and ob- 

 serving 534 



Allotropic transformations 220 

 Alloys, elastic constants 137 

 Amplitude of sound waves 535 

 Analysis of compound sound 

 waves 537 



and synthesis of periodic 



motions 506 



Angles, measurement 99 

 Annealing 168 

 Anomalous dispersion 389 

 Aperture of microscope ob- 

 jectives 323 

 Apparatus 38 



for photomicrography 333 



for projection 339 



for spectrum analysis, gene- 

 ral 342 

 Applications of photography 



449 



Areas, measurement 98 

 Astigmatism of eye 487 

 Astronomical refraction 347 

 Atmosphere, optics, general 



346 

 Atmospheric absorption 352 



refraction 347 



