Ch. IV] 



EXPERIMENTS FOR INTERPRETATION 



123 



the advice of Beale, p. 248, and examine first with a low power then 

 with a higher power; mounted dry, then in water; Hghted with re- 





i-f— r --i 



,^kk^kkkW,'\kkW.'g!!^ 



^'J^VV^k ' gy^VV'^XVNVVVVVVVVVVV^^^^ 



Fig. 74. 



Comparison Ocular for Placing Half the Fields of Two 

 Microscopes Side by Side, (if' R^). 



(Bausch & Lomb Optical Co., from Chamot). 



T^ To fit into the tube of the left microscope. 



7^ To fit into the tube of the right microscope. 



i^ Prism to reflect the beam from the right microscope to the prism R', 

 whence it is reflected up through the ocular (O) into the right half of the field 

 shown above in the face view. 



P'R^ The prism and left half of the field shown in face view in the diagram 

 at the top. 



fleeted light, then with transmitted hght, the following: potato, wheat, 

 rice, and com starch (easily obtained by scraping the potato and the 

 grains mentioned); bread crumbs; portions of feather (portions of 

 feather accidentally present in histological preparations have been 



