328 J. M. COON ON A NEW FINDER FOR THE MICROSCOPE. 



on one microscope can with equal readiness have parts_ found on 

 any other instrument, and any number of parts can be found 

 successively without the removal of the slide'-from the stage, or 

 refocussing, which is of great moment when using immersion 

 objectives or condensers. In fact, it is easier to find objects with 

 it than by means of the mechanical stage, because the light and 

 divisions are often inconveniently placed. 



The actual design of this finder may vary, but it essentially 

 consists of a means for attaching to the microscope a pointer with 

 universal movement. That exhibited this evening has a plain 

 clamp, with a milled-head screw for fastening it to the stage ; 

 and on the clamp is mounted a pointer- holder with horizontal 



Fig. 1. 



motion, a screw through which holds the pointer, having a 

 vertical and sliding motion, and which also clamps the pointer 

 when adjusted. 



In conjunction with this finder a registering label is used. This 

 may be ruled in many ways, but the author has found the method 

 shown in Fig. 1 very suitable and simple. Vertical columns of 

 squares are indicated by capital letters at top and horizontal lines 

 numbered at the side. Each square is sub-divided into four smaller 

 ones, indicated by small letters, a, b, c, d, each small square being 

 divided by diagonal lines into four triangles. The side of each 

 square measures 1*25 mm., and by the triangles it is easy to locate 

 the position of the pointer to one-fifth of this — or, say, '25 mm. or 



