IV] 



MEASUREMENT OF OBJECTS 



ascertained distance from it. Fix a piece of smooth 

 paper in the middle of the drawing-board. 



Slip the ring (r) over the tube of the microscope (t), 

 then replace the eye-piece (o). Arrange the brass rod 



Fig. 2. The upper sketch shows the camera from the side, 

 the lower sketch shows it from above. 



carrying the prism (A) on the left-hand side and shift 

 the prism till (1) the edge (a) stretches half-way over 



