Ocean Temperatures along the West Coast of North America. 055 



directed at an angle of 45 to the right of the wind velocity, thus 

 coinciding with the arrow (V ) of (Fig. 5). Now, if as we descend, the 

 successive edges are shortened so as to have the successive lengths of 

 the arrows of the diagram (Fig. 5), each edge will represent in magnitude 

 and direction the velocity of the water at that depth. And by the 

 time a half turn had been made the edge of the step, that is, the 

 velocity of the water would be only 1 / 20 of its value (V ) at the top, 

 and from there downward the velocity would be still smaller. So, for 

 practical purposes we can neglect the motion below that point. 



The total momentum of the "wind-current u is directed at right 

 angles to the wind itself. The flow or volume of water per unit time 

 transported 3 ) parallel to the wind is zero, and that perpendicular to 

 the wind is 

 4 VoP 



Therefore, the direction and magnitude of the flow depends only on 

 (Tj) and not upon (p). Within this surface layer of thickness (D) it is 

 evident from (Fig. 5) that water is actually transported in various 

 directions and that the amount carried per unit time in a layer of given 

 thickness decreases as the depth increases. But when we add up the 

 amounts flowing parallel to the wind in the whole layer, it is found 

 that there is as much water flowing with the wind as against it, so 

 the total quantity per unit time, that is, the flow parallel to the wind 

 is zero. While when we sum up the amounts moving normal to the 



wind the value [(^JTJ=) = y (V D)J is obtained, the direction or the 



flow being to the right of the wind. That is, a uniform wind blowing 

 over deep water in a region remote from any obstructions, will trans- 

 port water only at right angles to its own direction, the flow being the 

 same as if the velocity of all the water in the layer of thickness (D) 

 was directed to the right of the wind and the magnitude was 2 /o of 

 its value at the surface. 



The experimental value of (p) for laminar motion is about 0,014, 

 and when substituted in (2) gives the value 



44 



5. D = TT^F F centimeters. 



y sin* 



The theory of Zoppritz is based on exactly the same assumptions as 

 the above except that the influence of the earth's rotation is neglected, 



J ) Thru a vertical rectangle of unit width and perpendicular to 

 the direction of the motion. 



