PLATE 3. 



Direct Colour Photomicrograph. 



Screen-plate process (Dufay). 



PART OF THE "EYE" IN TAIL FEATHER OF PEACOCK x 12 



Objective 3" Achromat. 



Ocular Watson's B. 



Illuminant .... Sunlight. 



Condenser ... Bull's-eye, projecting convergent beam. 



Screen Dufay compensating screen for daylight. 



Plate Dufay colour plate. 



Exposure 30 sees. 



Photomicrographs in colours of opaque objects are more difficult 

 to take satisfactorily than a subject illuminated by transmitted or 

 polarised light. It is necessary to have a very strong illuminant, in 

 this case sunlight. 



Photo. W. B. R. 



To follow page 3 



