136 



PKACTICAL PHOTO-MICKOGEAPHY 



is shown in position near to the objective on the camera-front, 

 the illuminant and bull's-eye condenser occupying a position 



On the triangular metal bar as shown. With the geometric- 

 slide principle carried out entirely, this triangular bar is of course 

 not necessary, the whole of the moving parts being carried on 

 the two metal rods as described. 



