Microscopical Essays, 



69 



b e is a handle furniGied with an imiverfal joint, for more con- 

 veniently turning the pinion. When the handle is removed, the 

 nut, Fig. 2, may be ufed in it's ftead. 



de is a brafs bar, to fupport the curved piece KI, and keep 

 the body A B firm and fteady. 



f g h i is the ftage for opake objecls ; it fits upon the bar 

 QRST by means of the focket h i, and is brought nearer to, 

 or removed further from, the magnifying lens, by turning the 

 pinion a : the objecls are placed in the front fide of the ftage, 

 (which cannot be feen in this figure) between four fmall brafs 

 plates ; the edges of two of thefe are feen at k 1. The two upper 

 pieces of brafs are moveable ; they are fixed to a plate, which is 

 acled on by a fpiral fpring, that prefies them down, and confines 

 the Aider with the objecls; this plate, and the two upper pieces 

 ©f brafs, are lifted up by the fmall nut m. 



At the lower part of the ftage, there is a femicircular lump of 

 glafs n, which is defigned to receive the light from the lamp,. 

 Fig. 3, and to collect and throw it on the concave mirror O, 

 from whence it is to be reflected on the object. 



The upper part, fgrs, of the opake ftage takes out, that the 

 ftage for tranfparent objects may be inferted in it's place, 



Fig. 4, reprefents the ftage for tranfparent objeas ; the two 

 legs, 5 and 6, fit into the top of the under part rshi of the ftage 

 for opake objeas ; 7 is the part which confines or holds the 

 ftiders, and through which they are to be moved ; 9 and 10 a 



