Tables 273-275. 

 RADIATION CONSTANTS. 



TABLE 273.— Radiation Formols and Constants for Perfect Radiator. 



247 



The radiation per sq. cm. from a "black body" (exclusive of convection losses) at the tern- 

 perature T° (absolute, C) to one at /° is equal to 



J=,j{ T^—t^) (Stefan-Boltzmann) ; 

 where o-= 1.364 X lo-i^ gram-calories per second per sq. centimeter. 

 = 8.20 X 10-11 << <i '< minute " " " 



= 5.71 X lo-i'^ watts per sq. centimeter. 

 The distribution of this energy in the spectrum is represented by Planck's formula: 



/.=C,vs [/5-i]-i 



whereyX is the intensity of the energy at the wave-length A. (\ expressed in microns, ;u) and^ is 

 the base of the Napierian logarithms. 



Ci = S.S6 X io3 for / m 5- = 3.70 X 10* for / m ^ 



C<i= 14325 for \ in /It 

 /„„=3.ii X 10-I6 T^ for/ in 



gram. cal. 



1.30 X IO-15 T^iox J\n 



luatis 



sec. cm. 

 Amax T= 2885 for \m ijL 



h = Planck's unit = elementary " Wirkungs quantum "=6.554 X lo-^' ergs. sec. 

 k = constant of entropy equation = 1.37 X io"i'^ ergs. /degrees. 



TABLE 274.— Radiation in Gram-Calories per 24 Hours per sq. cm. from a Perfect Radiator at t° C to 

 an absolutely Cold Space (-273^^0. 



Computed from the Stefan- Floltzmann formula. 



TABLE 275. —Values of J\ for Varfons Temperatures Centigrade. 



Ekholm, Met. Z. igo2, used Ci:=8346 and C2= 14349, and for the unit of time the day. 

 For 100°, the values for JA have been multiplied by 10, for the other temperatures by 100. 



Smithsonian Tables. 



