66 



The Electron Microscope 



tempted which would have entailed even the smallest sacrifice of 

 performance. In spite of this an instrument was created, after 

 an astonishingly short time of development, which can be suc- 

 cessfully operated even by semi-skilled laboratory assistants ; a 

 fact which reflects the highest credit on the skill of the designers. 



Fig. 17. Type B floor model and experimental desk model of R.C.A. 



magnetic microscopes 



Figure 18 is a schematic section of the microscope. From top 

 to bottom, it contains the discharge tube, a flexible joint with a 

 double set of adjusting screws, the condenser lens, a second 

 flexible joint, the object chamber, the objective lens, a third 

 flexible joint, connecting the objective with the first throw, the 



