FINDERS AND INDICATORS. 191 



"bath of spermaceti, and, when nearly cold, cut out a 

 circular piece and secure it over the largest opening in 

 the diaphragm plate. This will materially moderate 

 and soften the light. 



Finders and Indicators. A finder, as applied to the 

 microscope, is the means of registering the position of 

 any particular object in a slide : as, for instance, some 

 particularly good specimen of a diatom, so that it may 

 be referred to at a future time. The subject will be 

 found fully discussed in the pages of the Journal of the 

 Royal Microscopical Society. The traversing stage of 



FIG. 126. Amyot's Object finder. 



the microscope admits of such finders as those of Mr. 

 Okeden, Mr. Tyrrell, Mr. Amyot (fig. 126), &c., being 

 used. The first named . (Mr. Okeden's) finder consists 

 of two graduated scales, one of them vertical, attached 

 to the fixed stage-plate, and the other horizontal, 

 attached to an arm carried by the intermediate plate ; 

 the first of these scales enables the observer to " set " 

 the vertically- sliding plate to any determinate position 

 in relation to the fixed plate, while the second gives 

 him the like power of setting the horizontally-sliding 

 plate by the intermediate. 



For those microscopists whose instruments are with- 



