PLATE XII. 



Fig. 53. 



Fig. 54. 



To illustrate the mode of examining an object by 

 reflected light with, the lieberkuhn. The light re. 

 fleeted from the mirror, a, passes through the glass 

 slide, 4. around the object, and impinges on" the 

 concave annular mirror, d, by which the rays ara 

 brought to a focus and condensed upon the object 

 placed at e. p. 21. 



Achromatic condenser mounted with a lever 

 handle, p. 24. 



Parabolic illuminator, showing course of a ray of light, m. n,f, when an uncovered object, a, 



is placed in" focus, p. -J3. 



Fig. 56. 



Arrangement of microscope for drawing and measuring objects. p. 27. 



[To face page 24. 



