808 



SMITHSONIAN PHYSICAL TABLES 



rate of incidence, 639, 640 

 velocities, 640 

 Kundt's constant, 506 



L series {see also under X-rays), 696 

 Lambert, 93 



Lamps {see also Illuminants) : 

 arcs, carbon, 105 



mercury, 109 

 automobile, 107 

 carbon, 105 

 carbon arcs, 105 

 coiled-coil, 106 

 color of light, 111 

 CX, 106 

 early (incandescent), 105 



efficiencies, 105 

 filaments, coiled-coil, 106 



temperature, 106 

 flash tube, 111 

 fluorescent, 1 10 

 gem, 105 



incandescent {see Incandescent lamps) 

 large, 106 

 mercury arcs, 109 

 miniature, 107 

 photoflash, 110 

 photoflood, 106 

 photographic, 106 

 projection, 106 

 sealed-beam (all glass), 108 

 small, 107 

 street series, 106 

 tungsten, 106 



characteristics, 106 



efficiency, 1908-1948, 106 



temperature, 106 

 different types, 106 

 efficiency, 106 



various, 106 

 Langley, 9 

 Latent heat, 9, 165 

 fusion, 615 



alloys, 165 



beeswax, 165 



ice, 165, 167 



metals, 165 

 vaporization, 167 



ammonia, 167 

 liquid, 167 



elements, 165 



formulas, 167 



liquids, 166 



metals, 165, 366 



substances, various, 165 



total heat, 167 

 Latitude variation, 730 



Lead: age ratios, radioactive materials, 679 

 atomic weight, 619 

 common, isotope variation, 679 

 isotopes, 657, 662 



composition, locality, 679 

 protective thickness, X-rays, 693, 695 



materials relative to, 694 

 Least squares solutions, 37-44 



tables for, 40-47 

 Leather: diffusion constant, 232 

 density, 233 



Leather — continued 

 elongation, 232 



physical properties and humidity, 232, 233 

 tensile strength, 232 

 thermal conductivity, 233 

 thermal expansion 



cubic, 233 

 types of, 232 

 Leduc effect, 507 

 Length, unit of, standard, 14, 60 

 Light: color, various sources, 104 

 defined, 87 

 definitions, 93 



filters, red pyrometer glass, 537 

 mechanical equivalent, 93 



minimum, 93 

 minimum energy for, 89 

 polarization, rotation plane, 557 

 quantity, 94 

 reflected, 549 

 scattering of, 3 

 sources and source materials, 102, 103 



characteristics, 102, 103 

 standards of intensity, 92, 94 

 symbols, 94 



transmission through space, 771 

 velocity, 47, 51, 54, 80 

 visual range of white, 92 

 white, 96 

 year, 731 

 Lightning, 614 

 channel, 614 



diameter, 614 

 constants, 614 

 current, 614 

 data, 614 

 peaks, 614 



interval between, 614 

 polarity, 614 

 potential, 614 

 cloud, 614 

 gradient, air, 614 

 beneath cloud, 614 

 quantity of electricity discharged, 614 

 single current peak, 614 

 total stroke, 614 

 strokes: 



cloud to ground, 614 

 polarity, 614 

 potential gradient, 614 

 energy, 614 



number strokes per mile 2 , 614 

 number strokes per year, 614 

 thunder, 614 

 velocity, 614 

 Light-year, 730 



Lime-alumina-silica compounds, 130 

 eutectic mixture, 130 

 melting point, 130 

 transformation, 130 

 Linear acceleration, 6 

 Linear accelerator, 657 

 Linear expansion: alloys, 149 

 elements, 145 

 materials, various, 152 

 Linear measurements, 62 

 Linear units, 62, 509 

 wavelength, 509 



