en. n 



DRAWING WITH THE MICROSCOPE 



149 



stage of the microscope. The mirror must have its edges in planes 

 parallel with the edges of the drawing board also (Fig. 130.) 



§ 206. Drawing with the Abbe Camera Lucida. — (A) The 

 light from the microscope and from the drawing surface should be 

 of nearly equal intensity, so that the image and the drawing pencil 

 can be seen with about equal distinctness. This may be accomplished 



Fig. 130. Bernhard's Drawing Board for the Abbe Camera Lucida- 

 This drawing board is adjustable vertically, and the board may be inclined to 

 prevent distortion. It is also arranged for use with an inclined microscope, 

 having the base board hinged, Microscope and drawing surface are then 

 inclined together. (Zeil. wiss. Mikroskopie, vol. VII., 1804, p. 298.) (Zeiss 

 Catalog. ) 



with very low powers (16 mm. and lower objectives) by covering 

 the mirror of the microscope with white paper when transparent ob- 

 jects are to be drawn. For high powers it is best to use a substage 

 condenser. Often the light may be balanced by using a larger or 

 smaller opening in the diaphragm. One can tell which field is ex- 

 cessively illuminated, for it is the one in which objects are most dis- 

 tinctly seen. If it is the microscopic, then the image of the micro- 



