204 
EDWARDS, ON FINDERS. 
the hope that this little contrivance may prove of as much 
use to others as it has heen to me, cheerfully submitting it to 
the consideration of microscopists. 
My second instrument I desire to call a registrar; it is, in 
fact an indicator, adapted to the use of microscopes with 
mechanical stages only, and wiU be found represented in 
figs. 3 and 4. 
In these illustrations (3 and 4) the stage is three inches by 
rig. 3. 
two, although, of course, this contrivance could be adapted 
to those of other dimensions. The stage, s, has a strip of 
brass, e, fastened to it, of the thickness and length of the 
glass slides. This strip is , arranged, at one half an inch 
from a line drawn through the centre of the circular hole in 
the stage, so as to bring the centre of the slide into the 
middle of the field of vision. 
On one side of the stage, at one and a half inch from the 
centre, is fixed a piece of ivory, i, measuring one and one 
tenth of an inch each way, and ruled with lines cutting each 
other across at one fiftieth of an inch apart the side strip 
(as a, in fig. 3) is reserved for the numbers, which run frbm 
* In the figure, the lines are represented at only ^th of an inch apart, 
to save the engraver trouble. 
