126 



MAGNIFICATION AND MICROMETRY [CH. IV 



the Ocular Micrometer. — The table should be filled out by each 

 student. In using it for Micrometry and Drawing it is necessary to 

 keep clearly in mind the exact conditions under which the determinations 

 were made, and also the ways in which variations in magnification and 

 the valuatio?i of the ocular micrometer may be produced (§ 177, 178, 

 188, 195- 





OCULAR OCULAR 

 37 or 5° mm- 25 mm 







Objective. 



Tube 

 in 



Tube 

 out 



MM. 



Tube 

 in 



Tube 

 out 



MM. 



Ocular Micrometer 



Valuation, 

 tube in. out mm. 





X 



X 



X 



X 









X 



X 



X 



X 









X 



X 



X 



X 









X 



X 



X 



X 









X 



X 



X 



X 









X 



X 



X 



X 







Simple Microscope. 



X 



Fig. 115 

 micrometry 



§ 180. Micrometry is the determination of the size of objects 

 by the aid of a microscope. 



MICROMETRY WITH THE SIMPLE MICROSCOPE 



§ 181. With a simple microscope (A), the easiest and best 

 way is to use dividers and then with the simple microscope deter- 



