DO AND DO NOT IN MICRO-PROJECTION 



[CH. IX 



21. Be sure that the carbons 

 are in the correct mutual posi- 

 tion to give a good light. A 

 screen image of the burning 

 carbons often is of real help 

 (381). 



21. Do not omit the correct 

 setting of the carbons. A good 

 light cannot be produced with 

 the carbons in the wrong mutual 

 relation. 



2 2 . Mask the preparations for 

 exhibition ( 384). 



23. Remember the advan- 

 tages of a large field for seeing 

 the relation of parts (387). 



2 2 . Do not exhibit specimens 

 which are not properly masked. 

 It is necessary to be able to 

 work with certainty and rapid- 

 ity in an exhibition. 



23. Do not forget the impor- 

 tance of a large field so that the 

 relations of parts can be seen. 



24. Remember that one can 

 do good projection work with 

 an ordinary microscope ( 393). 



25. For objects which must 

 remain in a horizontal position, 

 a vertical microscope must be 

 used; this involves the use of 

 two mirrors or of a mirror and a 

 prism to reflect the light upward 

 and then horizontally to the 

 screen (397)- 



24. Do not forget that one 

 can do very good work by using 

 an ordinary microscope in pro- 

 jection. 



25. Do not try to use a hori- 

 zontal microscope when one in a 

 vertical position is called for. 



26. Have everything in per- 

 fect order and adjustment when- 

 ever an exhibition of micro- 

 scopic objects is to be made. 

 Haphazard work will give only 

 haphazard results ( 400). 



26. Do not do haphazard 

 projection. 



