264 



HYDROGRAPHIC MANUAL 



7-31 Trigonometric functions for circle-sheet construction. — For use in constructing circle 

 sheets (see 5-31) a table of natural half -cosecants and half-cotangents to four places is given. 

 The values are given for each 10 minutes from 1° to 20°, for each half-degree from 20° to 50° 

 and for each degree from 50° to 90°. 



Table 18. — Natural half-cosecants and half-cotangents 



