130 



Table X. — Correction factor i/B 



262. Examples. — The primary current in a section of the Cape Cod 

 Canal, at the time t after a lunar transit, as derived in paragraph 249, 



^^' y=5.27 sin (m2^+124°02') 



and its angular lag, 0, is 10°. 2. 



The corrected velocity at say 3 lunar hours after a lunar transit 

 is to be found. When Hs reckoned in lunar hours m2 = 30°. Then, at 

 the given time, a«+|8=90°+124°02' = 214°.03. Since this angle lies 

 between 180° and 360°, table X is entered with 4>=10°.2 and 



ai+/3=214.03°-180° = 34°.03 



The corresponding value of i/B is, by interpolation, +0.14. Revers- 

 ing the sign, and multiplying by 5=5.27, the correction is —0.74 feet 

 per second. The primary current at the given hour is 



5.27 sin 214°.02'=-2.95 



and the corrected velocity is —3.69 feet per second. 



263. The distortion of the primary current curve in this section of 

 the canal, derived by applying the correction at successive lunar hours, 

 is shown in figure 41. The distortion of the primary current curve in 

 a section of the Delaware River (par. 251 and fig. 39), is shown in 

 figure 42. In the latter case B is 1.96 feet per second, and ^ is 36°. 



