VISIBLE AND NEAR-VISIBLE RADIATION 



137 



the right, and wave numbers in reciprocal centimeters on a logarithmic 

 scale increasing to the left. Values of radiance may be converted into 



-) 



o 

 O 



IxlO-" 



2x10^ 



IxlO' 



2.10* 1x10* 5xlO' 



RECIPROCAL CENTIMETERS 

 Fig. 3. — Spectral distribution of radiation from black body and tungsten. Ordinates 

 give logio radiance in ergs/steradian/cm.-/cm. wave-length in a direction normal to the 

 surface. Abscissas give wave-lengths in ix increasing to the right, and wave numbers in 

 reciprocal centimeters increasing to the left. Full-line curves are for black body. Dotted 

 curves are for tungsten. 



watts/steradian/cm.2 by subtracting 7.0 from the logarithm. In order 

 to obtain the radiation in the entire hemisphere, these values must be 



