MICROSPECTROSCOPY AND MICROSPECTROPHOTOMETRY 



253 



After being reflected in the 45°-slanted semi-transparent mirror G, 

 the light enters the objective O^ which images, on the investigated 

 specimen P, the hole T reduced by the magnification of the objective 

 Oi used. This is the image that serves to illuminate the detail in- 

 vestigated. Since any diameter can be given to it, only the detail 



Fig. 10.10. Mcrospectrophotometric arrangement in which the light originated from 

 the monochromator passes through the microscope in reverse. 



investigated need be illuminated. The condenser C sends the light 

 having passed the detail investigated to the cell R. By means of a re- 

 tractable mirror, not shown in Fig. 10.10, the specimen can be illumi- 

 nated and observed in the customary way. If the image plane /*', 

 observed through the eyepiece O2, is symmetrical with the diaphragm T 

 in relation to the semi-reflecting face of the mirror G, the specimen 

 and the imaged aperture T in the latter are seen by diifusion. This 

 enables one to ascertain that the detail observed is the one to be 

 photo-analysed. Proper ahgnment can be checked by means of 

 a reticle, at A' . Luminosity of the device can be increased by leaving 

 the slit of the monochromator at T and inserting a cyhndrical lens 

 between G and T. In this way, all the light from the monochromator 



