CANADIAN FISHERIES EXPEDITION, 1914-15 275 



geographical situation will be made. The last column in table 5 contains the velocities 

 thus calculated. 



As regards direction of the current, this will be easily understood from the fore- 

 going. The lighter surface water is pressed over to the right by the earth's rotation. 

 Placing myself, for instance, in the section so as to have the lighter water on the right 

 hand, and heavier on the left, I am then facing in the forward direction of the cur- 

 rent. 



It will also be evident from the foregoing, that the method in question gives only 

 the component for current velocity in a direction at right angles to the section. This, 

 however, is in the present case of but slight import, as Dr. Hjort has for the most part 

 taken his sections in such a manner as to have them almost at right angles across the 

 currents found. Dr. Hjort's measurements are, from a dynamic point of view, ideal 

 in this respect. 



In table 5, eight points of the compass have been used to designate the direction 

 of the current. As usual, in dealing with ocean currents, the letter indicates the direc- 

 tion towards which the current flows. Thus E, for instance, denotes a current flowing 

 from west to east. 



Plates XIV and XV have been drawn up from the figures in the last column of 

 table 5. The former gives the calculated velocities for spring, the latter for summer, 

 1915. From the intimate relation of these velocities to the number of solenoids (vide 

 table 5), it follows that Plates XIV and XV also afford the best possible graphic pre- 

 sentment of the distribution of solenoids throughout the area of investigation. 



14.— INFLUENCE OF FEICTION UPON CIECULATION. 



The influence of friction R upon the circulation of a closed curve, may be cal- 

 culated in two different ways; either directly, from measurements of velocity taken for 

 the purpose, or indirectly, by means of Bjerknes' equation for circulation, all the 

 terms of this being known with the exception of R. 



In the former case, three uniform current meters are set out on one and the same 

 line, with say 5 metres vertical inter\'al between each two, with which systems a'f 

 instruments measurements are then taken at the different depths. From the measure- 

 ments thus obtained, the parabolas for diagram of velocity are then constructed, and 

 from these again the acceleration of the frictional force can bf calculated (chapter 9). 

 By integration of the tangential component for this along the closed curve, we obtain 

 R. 



In the second case, we have, according to (6), 



„ , d S dC 



When the movement is stationary, ^ , disappears, and we have, 



dt 



R = A—2 CO 4t- (^2) 



d t 



If the closed curve lies along a stationary current, then 2oj -^ will likewise dis- 



dt 



appear, and we obtfiin 



E = A (13) 



