MICROSPECTROSCOPY AND MICROSPECTROPHOTOMETRY 



261 



Appearance of the field is shown in Fig. 10.17. The image A\ 

 whose luminance is being measured, is compared with the comparison 

 area A[., whose luminance is adjustable acl libitum. Such adjustment 

 may be made in several ways. In Fig. 10.16, luminance variation of 



M 



u(2) 



cz 



3 V 



M. 



(I) 



M, 



^ 



3 P 



Fig. 10.16. Leitz's microscope-photometer (Berek). 



Fig. 10.17. Field aspect. 



the comparison area is obtained by means of the two polarizers A^i 

 and TV... Rotating tVo, whose orientation is shown by a graduated 

 circle adjusts the luminance of the comparison area until luminances 

 of A' and A'^ are equalized. The filter V enables one to provide the 



