Jtn Wu 
Width of light-box lens opening = w 
w 
w 
— Diameter of pin hole =d 
Mean 
water 
level 
Mean 
water 
level 
{ 
Concave Surface 
(a) Geometry 
Partially-illuminated 
spot 
Fully-illuminated 
Degree of Signal Saturation 
U.05 0.) O75) i} 5 
Radius of Curvature r (cm) 
(b) Calibration 
FIGURE 3 - CURVATURE RESPONSE OF OPTICAL INSTRUMENT. 
1462 
