CH. IX] PROJECTION MICROSCOPES ON THE MARKET 299 



However, many opticians are coming to finish their apparatus 

 in black, and all of them are ready to make modifications in their 

 instruments which they are convinced will make them more effec- 

 tive and convenient for those who are to use them. But as many 

 men have many minds it is not possible for the manufacturers to 

 please every one in all particulars, hence the apparatus in the open 

 market must represent a kind of average. While the authors 

 realize the limitations mentioned above, it is a pleasure to be able 

 to assert without reserve that the quality and design of the appa- 

 ratus obtainable at the present time are excellent. 



434. As the projection microscopes most common in America 

 are of German, English and home manufacture some examples are 

 illustrated below. 



FIG. 163. LEITZ PROJECTION MICROSCOPE. 



(From Leitz Catalogue}. 



1 Arc lamp. 



2 Condenser next the arc lamp. 



3 Water-cell. 



4 The lantern-slide holder. 



5 Iris diaphragm. 



6 Biconcave, illuminating lens to give the light the right angle before it 

 enters the substage condenser. 



7 Stage and substage condensers, on a revolver for use with different powers. 



8 Projection objectives on a revolving nose-piece. 

 Q Projection oculars on a revolver. 



The enclosing curtain is turned over the top to uncover the parts. (Sec fig. 

 96 for the entire apparatus in its latest form, 1914). 



