2 47 



TABLES 273-275. 

 RADIATION CONSTANTS. 



TABLE 273. Radiation Formula and Constants for Perfect Radiator. 



(exclusive of convection losses) at the tem 



J = ff ( T /4) ( Stef an-Boltzmann) ; 

 where <r= I-374X io~ 12 gram-calories per second per sq. centimeter. 

 = 8.26 X lo- 11 " " " minute " " 



= 5.75 X io~ 12 watts per sq. centimeter. 

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



where J\ is the intensity of the energy at the wave-length A (A, expressed in microns, /u) and e it 

 the base of the Napierian logarithms. 



G = 9 .226 X 10* for / in gram ' Cal 2 ' =3.86 X 10' for / i 



sec. cm. 

 C 2 = 14350 for \in ft 



cm.~ 



watts 



/ = 3.ii X 10- 7* for / in .-- =1.30X10-" 7* tor / in 



see. cm. cm. 



Xmax 7=2910 for X in n 



h Planck's unit = elementary "Wirkungs quantum "=6.83 X io~ 27 ergs. sec. 

 k = constant of entropy equation = 1.42 X IO~ 16 ergs./degrees. 



TABLE 274. Radiation In Gram-Calories per 24 Hours per sq. cm. from a Perfect Radiator at P C to 

 an absolutely Cold Space (273 0). 



Computed from the Stefan-Boltzmann formula. 



TABLE 275. Values of JA for Various Temperatures Centigrade. 

 Ekholm, Met. Z. 1902, used ^ = 8346 and C 2 = 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 TOO. 



SMITHSONIAN TABLES. 



