798 



SMITHSONIAN PHYSICAL TABLES 



Dielectric constant — continued 

 insulating materials, 429 



at radio frequencies, 429 

 kerosene, 425 

 liquids, 425 



formula, 426 



pressure, 424 



temperature, 426 

 coefficient, 426 



wavelengths, long, 426 

 loss tangent of dielectric materials, 437 

 lucite, 438 

 materials (various), 427, 428 



dielectric, 437 



oils, 425, 426 



organic, 425 



pressure effects, 424 



silicone, 438 



soils, 440 



vaseline, 439 

 mica, 427 

 minerals, 428 

 nonconductors, 428 



radio-frequencies, 429 

 paper, 427 

 paraffin, 427 

 plastics, 437 

 quartz (fused) , 428 

 quartz crystals, 430 

 rochelle salt, 431 

 rock salt. 430 

 rocks, 426 

 rubber, 438 



artificial, 438 

 shellac, 427, 438 

 soils, 440 

 solids, 427 



standard solutions, 428 

 sulfur, 430 

 unit, 10. 423, 430 

 water, 425 

 woods, 438 

 Dielectric materials (dielectric constant and 



loss tangent) : amber, 438 

 ceramics, 437 

 crystals, 437 

 frequency, 437 

 glasses, 437 

 guttapercha, 438 

 liquids, 439 

 inorganic, 439 

 organic, 439 

 lucite, 438 

 nylon, 437 

 oils, 439 

 paraffin, 438 

 plastics, 437 

 rubber, 438 

 shellac, 438 

 solids, 437 

 temperature, 423 

 vaseline, 439 

 water, 439 

 waxes, 438 

 woods, 438 

 Dielectric properties of nonconductors, 428 



Dielectric strength, 421 

 air, 421 



electrodes, 421 



spacing, 421, 422 

 potential, 421 

 pressure, 422 

 voltage for spark: ac, 421 

 voltage for spark: dc, 421, 422 

 materials (various), 423 

 glass, 423 

 guttapercha, 423 

 kerosene, 422 



voltage for spark, 422 

 liquid air, 423 

 mica, 423 

 oils, 423 

 paper, 423 

 paraffin, 423 

 rubber, 423 

 unit, 423 

 Diffusion: aqueous solutions into water, 354 

 coefficients 



gaseous ions, 644 

 gases, neutral, 644 

 constants, water vapor through leather, 



232 

 gases, 356 



ions, positive, mobility in noble gases, 644 

 metals into metals, 356 

 vapors, 355, 356 

 Diffusivities for materials, 143 

 Digit, 5 

 Dimensional equations, 2 



examples, 57 

 Dimensional formulas, 2, 58 



use of, 3 

 Dimensional formulas of units, 2 

 derived, 58 

 dynamical, 58 

 electrical, 59 

 fundamental, 57 

 geometrical, 58 

 heat, 58 

 light, 58 

 magnetic, 59 

 mechanical, 58 

 photometric, 58 

 thermal, 58 

 use of, 57 

 Diopter, 5 

 Dip: horizon, 730 



magnetic, 468 

 Dipole moment, 441 

 inorganic, 441 

 organic, 441 

 unit, 441 

 Debye, 441 

 Discharge in air, 421 

 ac, 421 

 dc, 421 



effect of electrode shape, 421 

 effect of pressure, 422 

 length of gap, 421, 422 

 voltage required, 422 

 Disintegration, artificial, 651, 653, 669 



types, 669 

 Disk source, 95 



