104 



TABLE 83.— COLOR MINUS BRIGHTNESS TEMPERATURE FOR CARBON 



Brightness temp. °K 1600 c 



Color — brightness 2 



TABLE 90.— RELATIVE BLUE BRIGHTNESS, B, AND BRIGHTNESS IN 



CANDLES PER CM 2 C, OF SOME INCANDESCENT OXIDES AT 



VARIOUS RED (0.665 M ) BRIGHTNESS TEMPERATURES, S x 



5"= 1500 1700 1800 1900 2000 

 Material BCBCBCBCBC 



Blackbody 026 .91 .27 5.3 .74 12.0 1.80 24.0 3.9 47.0 



Tungsten 038 .84 .41 5.9 1.11 14 2.7 33 6.3 74 



Urania, gas air and oxy-gas... .028 1.02 .31 6.6 .84 15 2.0 35 4.5 78 



Ceria, pure: Oxy-gas 035 1.08 .32 6.3 .83 14 1.9 31 4.0 62 



yellow: " 032 1.04 .32 7.1 .85 17 2.0 40 4.0 88 



brown: " 033 1.15 .30 6.7 .83 15 1.68 33 3.5 68 



Oxides of Ce group : Oxy-gas. .031 .97 .34 6.3 .92 14 2.3 33 5.0 71 



Neodymia: Oxy-gas 032 1.17 .33 6.9 .92 15 2.3 33 5.0 64 



Lanthana: " 033 1.11 .34 6.6 .89 15 2.1 33 4.5 64 



Erbia: " 047 1.71 .45 8.1 1.17 16 2.7 33 5.6 63 



Yttria, pure: Oxy-gas 067 1.18 .61 7.3 1.56 17 3.6 32 7.3 63 



95% pure: " 047 1.20 .46 7.3 1.19 16 2.8 36 5.9 75 



Zirconia: Oxy-gas 058 .73 .55 3.6 1.43 8 3.3 15 7.0 30 



Thoria: " 033 1.44 .56 7.5 1.40 16 3.1 32 6.3 63 



Alumina: " 076 1.45 .87 9.4 2.5 22 6.1 49 13.6 103 



Beryllia: " 086 1.62 .99 9.7 2.8 22 6.9 49 15.4 104 



Magnesia: " 21 2.4 1.31 11.0 2.8 22 5.6 43 10.2 79 



Thoria 1% ceria: Oxy-gas 078 1.45 .70 8.6 1.71 19 4.1 43 8.4 90 



l%urania: " 069 1.33 .67 8.3 1.77 19 4.1 44 8.7 93 



trace urania: " 059 1.33 .68 8.3 1.93 19 4.8 44 10.5 93 



1% neodymia: " 046 1.43 .43 7.1 1.14 15 2.6 29 5.5 56 



l%Mn oxide: " 035 1.13 .37 6.1 1.01 13 2.4 28 5.3 56 



TABLE 91.— COLOR TEMPERATURE, BRIGHTNESS TEMPERATURE, AND 

 BRIGHTNESS OF VARIOUS ILLUMINANTS 



Source T e 



Gas flame : 



Batswing 2160 



Candle shape about 10 cm high 1875 



Hefner as a whole 1880 



Candle : 



Sperm 1930 



Paraffin 1925 



Pentane 10-cp. std 1920 



Kerosene : 



Flat wick 2055 



Round wick 1920 



4 wpc carbon 2080 



3.1 wpc treated carbon 2165 



2.5 wpc gem 2195 



2 wpc osmium 2185 



2 wpc tantalum 2260 



Acetylene as a whole 2380 



One spot 2465 



Mees burner 2360 



1 .25 wpc tungsten 2400 



2.3 wpc Nernst 2400 



Sun: 



Outside atmosphere 6500 



At earth's surface 5600 



Clear sky 



Moon 



Welsbach mantle 



5"(X = .66S) 



Brightness 

 c/cm 2 



SMITHSONIAN PHYSICAL TABLES 



