356 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



towards each other. The six object glasses all screw together, one on 

 the top of the other ; they are intended to be nsed singly or in com- 

 binations of two or three, as indicated by the table of magnifications. 



Fig 56. 



A bull's-eye condenser is provided, and also a rectangular condensing 

 prism with two convex surfaces, mounted on an extending rod with 

 compass joint, to be fixed on the front hg for illumination above 



the stage. 



