428 



TABLE 445.— STANDARD SOLUTIONS FOR THE CALIBRATION OF APPARATUS 

 FOR THE MEASURING OF DIELECTRIC CONSTANT 



Did. 

 const, 

 at 18"C 



Substance X = oo 



Benzene 2.288 



Meta-xylene 2.376 



Ethyl ether 4.36 T 



Aniline 7.29 s 



Ethyl chloride 10.90 



O-nitro toluene 27.71 



Nitrobenzene 36.45 



Water (conduct. 10"*) . 81.07 



TABLE 446.— DIELECTRIC CONSTANT OF MINERALS* 



Wavelength, 



Material cm Range 



Asphalt 2.7 



Beryl °° 



Coal, anthracite 5.6-6.3 



Fluorite 6.8 



Glass, flint ex. heavy 9.9 



Glass, hard crown 7.0 



Glass, Jena barium 7.8-8.5 



Glass, lead (Powell) 5.4-8.0 



Gypsum 6.3 



Ice (— 2°C) 93.9 



Iceland spar 75 



Quartz, fused 3.5-3.6 



Sulfur, amorphous 3.9 



Dielectric constant 



j_ axis 



7.85 



6.05 



8.50 



8.00 



For reference, see footnote 45, p. 136. 



TABLE 447.— THE DIELECTRIC PROPERTIES OF NONCONDUCTORS 



Results of tests at unit area and unit thickness of dielectric 



At 1000 cycles Mica Paper Celluloid Ice 



Max. breakdown volts per cm 1.06X10 9 .71X10 9 1.05X10 9 .001X10* 



Specific indue, capacity 4.00 4.90 13.26 86.40 



Max. absorbable energy, watts-sec/cm 8 . .198 .108 .640 .00040 



90°-angle of lead 0° 57' 2° 10' 3° 40' 13° 39' 



Equiv. resistance (ohm-cm) X 10 11 3.91 9.84 48.3 1400 



Conductivity, l/(ohm-cm) X 10" 10 2.56 1.02 .207 .00722 



Percent change in cap. per cycle X 10 4 . . 2.18 14.31 30.7 70.0 



Percent change in resistance per cycle .. . .258 .146 .106 .127 



At 15 cycles 



Specific inductive capacity 4.09 5.77 18.60 429.0 



Max. absorbable energy, watt-sec/cm 8 . . .203 .126 .90 .002 



Percent change in capacity per cycle 00 .306 1.74 1.59 



On direct current 



Conductivity, l/(ohm-cm) 2.42X10"" 2.27X10" 14 71.5X10"" 163.10"" 



SMITHSONIAN PHYSICAL TABLES 



