Fig. 1. Diagram tx) show the parts of the compovmd microscope. (After Russell 



and Hastings) 



Oi, object; Oj, real image in F2, transposed by the collectlye lens to O3, real image 

 in eyepiece diaphragm ; O4, virtual image formed at the projection distance C, 250 

 mm. from eyepoint EP; CD, condenser diaphragm; L, mechanical tube length 

 (160 mm.) ; 1, 2, 3, three pencils of parallel light coming from different points of the 

 source of illumination. (After Bausch & Lomb Optical Co.) 



