IS? 



THE MICKOSC01T. 



"Lieberkuhn," from its celebrated inventor, -was for- 

 merly much in use as a re- 



tleetor, but is uow almost 

 abandoned, or rather replaced 

 by other and better contriv- 

 ances. The Uoberkiilm is 

 generally attached to the 

 object -class, in the manner 

 represented at tig. 1'Jl. Nvhoro 

 a exhibits the lowor part of 

 the compound body, /, the 

 object-glass, over whieh is 

 slid a tube and the Lieber- 

 kiilin, ( \ attached to it ; the 

 ra\ s of lii^-ht retleetevl fi'oin 

 the mirror are brought to a 

 focus upon an object </, 

 the mirror. The object may 

 a slip of Lrlass. or else held 

 en very small, or \\hen trans- 

 gum it to the dark \\ell, , 

 .'s opaqne disc-revolver (tig-. 





placed between it and 

 either be mounted on 

 by the forceps,/; NN ; 

 parent, it is better to 

 or mount it on Becl 



Beck eiVectcd a considerable 



improvement upon the 

 Liebcrkiihn by 

 the introduction 

 of the silver side- 

 retlector(fig.rJo), 

 \\hich causes the 

 shadows to fall on 

 the proper >ide, 

 and is employed on this account. This is ei: 

 into the stage of the microscope or used on a separate 

 Maud, so that it may be turned in any direction 

 towards the source of light The parabolic side- 

 reflector (fig. 123<i) is adapted for use with high 

 powers. 



^Sorby, while experiment imr with a reflector of the 

 kind, discovered the value of observing the peculiari- 

 ties of objects under every kind of illumination ; for, on 

 viewing specimens of iron and steel with this reflector, 



