5 8 ELEMENTARY PHOTO-MICROGRAPHY. 



connection is assured without danger of disturbing 

 adjustments. 



A reference to sketch will make this clear. 



The sliding block is secured by the thumb- 

 screws, and the figure which will now appear on 

 the ground-glass at the end of camera is examined. 



FIG. 26. 

 C, Cardboard tube. T, Camera tube. 



If the magnification be too small, the camera is 

 racked out ; or if too big, closed. 



The object is centred by means of the mechanical 

 stage. If size and position are correct, fine focus- 

 sing may be performed with focussing glass through 

 the transparent places at each corner and in the 

 centre of screen. 



Perhaps the object will be too brilliantly lighted 

 and the whole be drowned in a flood of light. If so, 



