MICROSPECTROSCOPY AND MICROSPECTROPHOTOMETRY 



251 



motor MO'), plots the curve showing absorption in terms of the 

 position within the specimen. 



Once the curve is plotted according to a specific path within the 

 object, the specimen should be shifted slightly in a perpendicular 

 direction. 



RC 



rLnnj^_ruLrLr 



Fig. 10.9. Motor MO actuates the specimen P through the selsyn Sli and Sl^, the screw V 

 and the device BitB-.ni. Motor MO drives also the recorder D whose pen / plots the 



absorption curve of the specimen. 



This shift is required in order to plot another absorption curve 

 according to a line parallel with the former. Such shift is provided 

 by a plate, set after the objective 0^, and whose tilt changes bring 

 about a slight shift of the imaged specimen. The arrangement is 



