014 



COMPOUND MICROSCOPE. 



clearly illuminated. The object to be examined must be placed on a slip of glass, 

 either with or without water, and a thin slip of microscopic glass be laid on it, 

 and then placed on the stage, e, in such a position as to be exactly in the axis 

 of the object glass or power employed ; the object is retained from slipping by 

 the sliding-piece, p, which serves readily to retain the object in the centre of the 

 stage ; the focus will now be easily obtained by turning the milled head, rf, so 

 as to raise or lower the body, a, as occasion may require, until on looking through 

 the instrument the object appears clearly defined. If the object is very opaque, 

 the light reflected by the mirror will be of no benefit ; it will, therefore, be neces- 

 sary to throw a powerful light on the object by means of the condenser, r, the 

 pin of which fits into the hole at the comer of the stage, and to view it with as 

 low a power as possible. The achromatic lenses, i, are used together for the 

 highest power, but must be separated, and one only employed, if a lower power 

 is required. The plano-convex lens, j, is for use in dissecting small objects, and 

 for mounting specimens. If the body, a, is removed, and the adapter, k, having 

 the object glass attached to it, be screwed into the arm, c, the instrument will 

 be converted into a simple microscope, well adapted for dissecting and examining 

 objects to prepare them for mounting to be viewed by the compound body and 

 higher powers. 



A more powerful instrument is shown by figure 830. This has a compound 

 body, sliding stage, revolving diaphragm, rack-work coarse adjustment, tangent 

 .crew fine adjustment, concave and plane mirrors, double pillar support on mas- 

 sive tripod base, two 

 sets of achromatic ob- 

 ject glasses and f 

 inch focus, shallow 

 and deep eye-piece?, 

 adapter for use in dis- 

 sections, mounted con- 

 denser, spring and 

 stage forceps, box for 

 live insects, selenite 

 stage, micrometer, po- 

 larising apparatus, and 

 objects mounted in 

 balsam. 



DESCRIPTION. The 

 stand, or base, con- 

 sists of a strong tri- 

 pod, a, supporting two 

 upright pillars, 6, 6, 

 between the upper 

 parts of which an axis 

 works. This carries 

 the whole of the opti- 

 cal parts of the instru- 

 ment, which can be 

 adjusted to any incli- 

 nation, horizontal, ver- 

 tical, or intermediate. 

 The stage, </, e, is 



