manufacturer that 80 

 per cent, of the in- 

 struments sold for 

 personal use are sup- 

 plied with a double 

 nose-piece when two 

 objectives are used, 

 and the triple when 

 three are taken. 



Bodies or Tubes. 



These are divided 

 into two classes, mo- 

 nocular, having one 

 body with which 

 observation is made 

 with one eye, which 

 may contain one or 

 two draw-tubes and 

 binocular for observa- 

 tion with both eyes, 

 in which the tubes 

 are fixed together at 

 the nose-piece and 

 gradually separate 

 until they reach the 

 pupillary distance. 

 The first would be a 

 monocular microscope, 

 the second a binocular 

 microscope. 



Fig. 25. 



