C. STACY FRENCH 



55 



ard lamp of known color temperature reflected off a magnesium oxide 

 block in the sample holder and interrupted by a 120-cycle chopper. 

 The apparatus retains its calibration for months. 



FLUORESCENT LIGHT 

 ENTERING SECOND 

 MONOCHROMATOR 

 TO BE ANALYZED, 



LIGHT CHOPPER 



TUNGSTEN STANDARD 

 LAMP FOR CALIBRATION 



FLUORESCENT SAMPLE 

 ORM3O FOR CALIBRATION 



MIRROR 



BLUE LIGHT FROM FIRST MONXHROMATOR 

 Fig. 3. Arrangement for illuminating the sample and for collecting the fluorescent 

 light. 



Figure 4 shows the monochromator used to separate the spectrum 

 of the fluorescent light into its different wavelengths. This analyzing 

 monochromator uses a reflection grating. The grating is rotated at an 

 adjustable speed by a motor which is also coupled to the cam and the 

 curve follower as illustrated in Fig. 1. 



Fluorescence Spectra of Extracted and Purified Pigments 



Phycoerythrin 



Figure 5 shows the absorption and fluorescence spectra of a sample 

 of phycoerythrin. Comparison of the absorption and fluorescence 



