How the Drag Is Caused 



stream it rushes along swiftly. The 

 line falls on this fast running water; 

 the fly, if unattached to a leader, would 

 pursue its way leisurely down-stream, 

 wherever the slowly flowing currents 

 naturally took it, but the gentle force 

 exerted upon the small insect is almost 

 immediately overcome by the powerful 

 pull of the line, and instead of follow- 

 ing its own natural course a very evi- 

 dent drag sets in. 



In Fig. 6, represents the position 

 of the angler, A the place where the 

 fly lights, and F the spot where the 

 strong midstream current exerts its 

 greatest force upon the line. The nat- 

 ural direction of the fly would be as 

 indicated by the line A B. But its 

 actual direction is the resultant of the 

 two forces acting upon fly and line, 

 and it follows approximately a direction 

 indicated by the dotted line A C. The 



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