THE MICROSCOPE. 



the object, which is sometimes done by mirrors, and sometimes 

 by lenses. In Fig. 30, L represents the cylinder of burning 

 lime, E E the reflector, which concentrates the light upon the 



Fig. 30. 



object O O; the rays from which, passing through the two plano- 

 convex lenses, are brought to foci upon a screen placed at a great 

 distance, and upon which is formed the magnified image. 



Fig. 31 shows a combination of lenses to condense the light 

 upon the object. In either case the optical arrangements by 

 which the image is formed admit of the same perfection as 



rATt 



CK 



those which have been described for the compound micro- 

 scopes. A few achromatic glasses for oxy-hydrogen micro- 

 scopes have been made, and they will ultimately become valu- 

 able instruments for illustrating lectures on natural history and 

 physiology. One made by Mr. Eoss was exhibited a few 

 months since at the Society of Arts to illustrate a lecture on the 

 physiology of woods. It should be observed, however, that 

 the oxy-hydrogen or solar microscope requires either a spheri- 

 cal screen, or that the objects should be mounted between 

 spherical glasses, in order to bring the whole into focus at one 

 time. This latter plan was adopted on the occasion just men- 

 tioned with perfect success. 



