22 Fly-rods and Fly-tackle. 



show-case, for example). B C (the level of the glass) 

 will then represent the " draft-line " of the hook ; and 

 as the line a of the inner side of the barb approaches 

 this line, short of actual coincidence, so will the sureness 

 of the hook increase, since then it will penetrate easily, 

 yet bury sufficiently. 



The demonstration of this principle, and the statement 

 of how it may be used to discriminate between hooks of 

 all forms, may be made in one breath. Let Fig. 7 rep- 

 resent the barbs of two hooks so placed; the line IB C 

 is the flat surface, and a a the line of the inner side 

 of the barb, as before. Now let us construct the par- 

 allelogram b c d e, of which the line a of the inner side 

 of the barb is the diagonal. 



Fig. 7. 



This is the well-known " parallelogram of forces " of 

 the books, and its well-settled principles teach us at a 

 glance that the side b c of the parallelogram (or that 

 parallel to the flat surface IB C) represents correctly the 

 penetrating power of the hook ; while the side c e (that 

 perpendicular to the flat surface) will show the relative 

 tendency of the hook to rake its way out of the fish's 

 mouth. Of course the intending purchaser, when he 

 places any hook upon the glass show-case of the dealer 

 in the position shown r can at once construct this paral- 



