CH. IX a] PROJECTION MICROSCOPE 251 



A. The ordinary Magic Lantern and the Projection Microscope 

 in position for alternate use (see Fig. 206 for wiring, etc.) i, Ammeter 

 shown at the left ; 2, ordinary stereopticon for lantern slides ; 3 

 Projection Microscope. This shows well the metal screen at the 

 bottom of the tube, for cutting off stray light. 



B. Projection Microscope with a 105 mm. objective for very 

 large objects. 



1. Stage with mechanical stage, large diaphragm opening and 

 section of a cat's brain as object. 



2. 105 mm. objective in position for projecting a large object such 

 as a brain section. 



3. Stage, near the condenser (See Fig. 209). 



4. Condenser with water bath. Under the condenser is a focus- 

 ing glass for photography. 



5. 90 degree, automatic arc lamp. 



6. Diaphragm with circular opening and specimen cooler in 

 position (See Fig. 208 F, G). 



C. Projection Microscope with the stage and microscope in posi- 

 tion for the use of a low objective. 



i. Large square diaphragm for the stage. 2. Microscope; 3, 

 Stage with the specimen cooler in position ; 4 Condenser and water 

 bath ; 5 Arc lamp. 



D. Projection Microscope with the parts in position for high 

 powers. 



1. Mechanical stage with a specimen in position. 



2. Microscope with a high power in position ; 3. Stage with the 

 specimen cooler in position ; 4. Condenser and water bath. 



5. Arc lamp ; 6. Large diaphragm. 



The white lines on the bed-piece indicate the position of the con- 

 denser, which is about 8 centimeters from the mica covering of the 

 condenser. The other line indicates the position of the microscope for 

 high power projection. 



FIG. 205 A. Zeiss' Micro-Planar for projection. (Cut loaned by 

 Bausch & Lomb Optical Co.) 



The micro-planars are of 20, 35, 50, 75, and 100 mm. equivalent 

 focus. When used for projection the special iris in each should be 

 wide open. These are used without a projection ocular. 



FIG. 205. B. C. Leitz objectives of 64 mm. (B), and 42 mm. (C) 

 for micro- projection. (Cut loaned by Wm. Krafft, N, Y.) 



