„42 
We have been able to see the bottom, that is, to pene- 
trate the water, with color photography to depths ranging 
from 8 or 10 feet in Alaska to 60 and even 70 feet over the 
coral bottom in certain parts of the Caribbean. At this 
time we are compiling bottom topography of an area off the 
coast of Puerto Rico and the Virgin Islands preparatory to 
hydrography. Bottom features are clearly visible on the 
color photography of this area. Depths measured on the 
Kelsh Plotter and corrected for refraction, when compared 
to prior hydrography, appear to be correct to plus or minus 
5% to maximum depths of 70 feet. 
CULEBRA ISLAND 
WEST INDIES 
65*16'30" " 
16° 65*15'45 
18* 1800" |es‘16 
18*18'00" 
  
  
  
18*17'30" 
65*16'30" 
  
  
  
  
18*17'30" 
65*15'45"