16 JULY 1950 



45^" MERIDIAN TIME 



17 JULY 1950 



Figure 26.— East-west and north-south components of current vectors after 

 ehmination of average current of 0.25 knots 129°. Smooth curves, shown 

 for comparison, are those representing a circular current of 0.35 knot ampli- 

 tude and 16-hour period. 



current measurements were resumed at 2345 and continued through 

 2345 on 17 July. The resulting series of 25 hourly velocities were 

 then added vectorially and a first approximation of the average 

 current determined graphically. 



This average current vector was then subtracted from each of the 

 individual current vectors to give the vectors representing the fluctu- 

 ating currents. The fluctuating current vectors were then broken 

 into their east-west and north-south components the magnitudes of 

 which were then plotted against time. As this plot showed that the 

 period of the principal constituent was of the order of 16 hours instead 

 of 25 hours a new average current vector was determined using the 

 16 hours beginning with 0145 on 17 July. This point was selected 

 to exclude the measurements of 1745 on 16 July and 0045 on 17 

 July w^hich were considered doubtful since there were indications 

 that the electrodes had not reached equilibrium with their surround- 

 ings at the time of the measurements. Figure 25 shows the vector 

 sum of the hourly velocities from 2345 on 16 July to 2345 on 17 July 

 and the determination of the average current for the 16 hours begin- 



83 



