ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



401 



selected from sand and other debris, differs from other similar forms 

 in that the base (into which the steel stem supporting the lens is 

 screwed) is made of a thick plate of glass, so that by placing a sheet 



Fig. no. 



of white paper beneath it, and using a bull's-eye condenser, opaque 

 objects can be easily selected for mounting. 



Fin. 67. 



Excelsior Pocket and Dissecting Microscope. — This instrument 

 patented by J. J. Bausch (Fig. 67) comes from tlie United States, 



