Ae 
Be 
C. 
D. 
E. 
F. 
7179 
Projector G. Spacing control for horisontal 
Projector lens grid 
Adjustable horizontal grid H. X-axis displacement control 
Fixed vertical grid 
Je Y-axis displacement control 
Platen for photographic paper K. Extra fixed vertical grids with 
Slot and set screw for adjusting other spacings 
anrle between horizontal and 
vertical grid lines 
Fig. 18. The "Harp". 
