176 



PRACTICAL PHOTO-MICROGEAPHY. 



ticular focus, so that in practice a Lieberkuhn is required for 

 each objective used with it. 



FIG. 41. MOUNT FOR LIEBERKUHN. 



Failing a Lieberkuhn for opaque-mounted objects, we may 

 have recourse to any other system of condensing rays of light 

 upon our object. Thus the light may be thrown upon the 



FIG. 42. SIDE REFLECTOR. (SWIFT.) 



object through a bull's eye, which should be placed at an angle 

 as narrow as possible to the plane of the object, i. 0., as near 

 as possible to the microscope tube. 



