COMPOUND MICEOSCOPE. 



767 



In figure 946 a compound microscope is represented. The stand or 

 base consists of a strong tripod, a, supporting two upright pillars, 6 6, 

 between the upper parts of which an axis works. This carries the 

 whole of the optical parts of the instrument, which can be adjusted to 

 any inclination, horizontal, vertical, or intermediate. The stage, d e, 

 is firmly attached to the axis, as is also the double mirror, /. The 

 triangular bar, g, has a rack on its posterior part, which is worked by a 

 pinion, the miUed heads of which are seen at h h. The body, i, 

 screws firmly into the arm, j ; the achromatic object-glasses are screwed 

 into the body at TO ; the Huyghenian eye-piece slides into the other 

 end of the body. The mirror is plane on one side, and concave on the 

 other, and is fitted with a universal movement, so as to be inclined 

 in any desired position. The milled heads, h h, by being revolved, 

 raise or lower the body, i, and constitute the coarse adjustment ; the 

 fine adjustment is effected by turning the miUed head,^. The object 

 to be examined is placed on the stage, d, and retained in the required 

 position by the sliding piece, e. The quantity of light admitted through 

 the instrument may be modified by the diaphragm, r, which consists 



Fig. 94r. 

 Pig. 947. Hartnack's (Oberhauser's) student's microscope. 



