OPTICAL INSTRUMENTS. 

 Fig. 660. 



Fig. 662. 



Botanical Lenses, or Magnifiers. The haste with which 

 botanists, &c., frequently have occasion to view objects, 

 renders a pocket magnifier very useful. The most conve- 

 nient of any constructed are those represented in Figs. 660, 

 661, and 662, which are drawn of the medium size, there 

 being a size smaller and one larger ; this form of mounting 



VjQL. II. 15 



