Microscopical Essays. 



To ufe this micro fcope, place the objeft on the ft age, rcflecl:. 

 the light on it from the concave mirror, and regulate it to the 

 focus, by moving the ftage nearer to or further from the lens at 

 B. The ivory Aiders pafs through the ftage • other objects may 

 be fixed in the nippers L M, and then brought under the eye- 

 glafifes ; or they may be laid on one of the glaffes which fit the 

 flage. 



The apparatus to this inftrument confifis of three ivory Aiders, 

 a pair of nippers, a pair of forceps, a fiat glafs, and a concave 

 ditto, both fitted to the ftage., 



Bo T A N IC'AL M'A'G N IFIERS, 



Since botany has been cultivated with fo much ardor, it has 

 been found neceffary to contrive fome very portable inftrument, 

 by which the botanift might inveftigate the objed of his purfuits, 

 as it rifes before him. Figures 7 and 8, Plate VIII reprefent 

 two, the moft convenient of this kind; 



In the cafe, Fig. 8, are three lenfes, g, 4, 1, of different mag- 

 nifying powers, that all turn up and {hut into the cafe. 



Fig. 7 contains alfo three lenfes, a> b,.d, of different foci, which 

 are all made to turn into the cafe, and may be ufed combined or 

 ieparately. 



The three lenfes in themfelVes afford three different magnify- 

 ing powers ; by combining two and two we make three more ; 

 the three together make a feventh magnifying power with three 



lenfes- 



