286 ON EARTH-CURRENTS, AND THE DIURNAL 



TABLE Y. 



16. The numbers in the fourth and seventh columns of the 

 foregoing Table are graphically represented in the annexed 

 diagram (Plate II., fig. 1), which accordingly exhibits the law 

 of the changes for the entire year, the radius- vector of the curve 

 measuring the intensity of the current, and the angle which it 

 makes with the meridian, its azimuth. The corresponding hours 

 are indicated on the perimeter of the curve, the afternoon hours 

 being distinguished by brackets. It will be seen that in the early 

 hours of the morning, namely, from 1 A. M. to 6 A. M., inclusive, 

 the direction of the current changes little ; its mean azimuth for 

 that period is N. 21 W. At 7 A. M. the current begins to move 

 eastward, and its direction is due north at about 7 h 15 m . At 

 10 h 25 m A.M., the azimuth of the resultant current is 90, or its 

 direction is to the cast; at 3 h 15 m P.M., it becomes south; and at 



