LENSES. 155 



lens is one that shuts up in a tortoise-shell 

 or german-silver case, like Fig. 99, and 

 which may be purchased for two or three 

 dollars. Such a little lens will magnify- 

 enough for purposes of common out-door ob- 

 servation. A stand may be made for it by 

 fastening a wire two inches long vertically 

 into a block, and then sliding the lens down 



Fig. 100. 



upon the wire by means of the hole in the 

 handle. Then if a couple of needles be 

 stuck in sticks, as represented in the lower 

 portion of Fig. 99, and used as priers and 

 forceps, both hands may be employed in 

 picking a flower or bud to pieces, while the 

 eye watches the whole operation through the 

 microscope. An excellent lens for examin- 

 ing rather large objects and for studying 

 plants without dissecting them is a reading- 

 glass two or three inches in diameter, as 

 shown in Fig. 100. 



