330 



DRA WINGS FOR MODELS 



[ CH. X 



avoid distortion ( 204). For getting the exact magnification 

 desired one has recourse to different oculars, objectives and distance 

 of the drawing surfaces ( 177, 206 E). 



By far the most satisfactory means for making the numerous 

 drawings of all sizes of object and all magnifications except the high- 

 est, is the projection microscope ( Fig. 258). 



One can draw directly upon blotting paper, but it is so import- 

 ant to have a drawing to refer back to that one or more duplicates 

 should be made. This is easily accomplished by putting a sheet of 

 carbon manifolding paper on the blotting paper and a sheet of thin 



FIG. 258. Room and Apparatus for Drawing with the Projection Micro- 

 scope. R. Radiant, an arc lamp with carbons at right angles; L. t. Lamp 

 and microscope table; C. Condenser with W. a large water bath between the 

 lenses to absorb the heat rays. S. w. Stage and stage water bath on which 

 rests the object and keeps the object cool by radiation as well as by absorption; 

 O. The objective representing the microscope; M. M^irror at 45 on a draw- 

 ing table, (Dt.) As the microscope is horizontal so that the axial ray is re- 

 flected downward at right angles by the 45 mirror there is no distortion. 

 The scale of the drawing is added exactly as described in \ 207. 



