82 



Microscopical Essays. 



magnifier that is then ufed ; reflect the light from the concave 

 mirror G to the fiker fpeculum, from which it will again be re- 

 flected on the object.. The glafles are to be adj lifted to their 

 focal -diftance as before directed. 



A List of the Apparatus of Cuff's double-constructed 



Microscope. 



H a convex lens, to collect the rays of light from the fun or a 

 candle, and condenfe them on the object. 



L a cylindrical tube, open at each fide, with a concave fpecu- 

 lum fere wed to the lower end h. 



P the Aider-holder ; it confifts of a cylindrical tube, in which 

 an inner tube is forced upwards by a fpiral fpring, it is ufed to 

 receive an ivory Aider K, which is to be Aid between the plates h 

 and i. The cylinder P fits the hole n in the ftage : the hollow 

 part at k is defigned to receive a glafs tube N. 



R is a brafs cone, to be put under the bottom of the cylinder 

 P, to intercept occafionally fome of the rays of light. 



S a box containing a concave and a flat glafs, between which a 

 fmall living infect may be confined ; it is to be placed over the 

 hole n. 



T a flat glafs, to lay any occafional objeel upon ; there is alfo 

 a concave one for fluids. 



