24 THEMICROSCOPIST. 



to the upper and lower of which the stout wires, d, e } are rivet- 

 ted. The middle plate, b, which forms the stage for carrying 

 the objects, is made to slide up and down on these wires. The 

 upper plate, a, carries the lenses, i, and the lower one, c, some- 

 times carries a mirror, for reflecting the light of a candle or of 

 the sky through any transparent object which may be placed 

 on the stage. Into the stage a dissecting knife, h, a pointed 



Fig. 2. 



instrument, /, and a pair of forceps, </, are made to fit, and can 

 be readily taken out for use by sliding the stage down nearly 

 to the mirror. 



A very useful kind of simple microscope was that invented 

 by Mr. Wilson ; an early form of which is represented by Fig. 

 3. The body, A, A, A, A, which was made either of ivory, brass, 

 or silver, was cylindrical, and about two inches in length, and 

 one inch in diameter. Into the lower end, B, the magnifiers 

 are screwed, and into the upper end screws a piece of tube, D, 

 carrying at the end, C, a convex glass, and on its outside a 

 male screw. Three thin plates of brass, E, are made to slide 



