102 



PROGRESS IN MICROSCOPY 



The objectives O^ and O.y are corrected for infinity and the lens exhibits 

 two superimposed images of P and R that are observed in the eye- 

 piece O2. The condenser (not shown in Fig. 3.8) is at C. The path 

 difference between the two paths (1) and (2) is varied by means of the 



Oj 



Fig. 3.8. Leitz interference microscope. 



parallel-sided plates J, and (L. There are, hence, two separate but 

 identical microscopes: one (I) enclosing the object P and the other (2) 

 not enclosing anything (the glass slides at P and R are identical, too). 

 The microscope (1) exhibits an image interfering with a reference flat 

 wave originated by the microscope (2). No spurious image need, 

 therefore, be expected. 



