236 Fly-rods and Fly-tackle. 



5th. It strengthens the rod ! And this is the only as- 

 sertion in its favor I have ever been able to elicit. 



But is this assertion true? I believe that it is not 

 only false, but that the direct contrary is the truth. A 

 ferrule may be able to endure any possible strain with 

 impunity, while the rod to which it is applied may be as 

 brittle as a pipe-stem. Of course the weakest point in 

 the rod measures the strength of the rod. 



This is just the case in point. A dowelled ferrule in 

 itself is undoubtedly stronger than a simple ferrule, but 

 the rod to which it is applied is weakened thereby, and 

 is not as strong as it would be were a simple ferrule of 

 proper construction substituted in its place. The strain 

 brought on the unyielding metal is localized and concen- 

 trated at its extremities. The ferrule and its mate act 

 as one single lever, in which the power is applied at one 

 end, while the fulcrum is at the other. It is elementary 

 and axiomic that the longer the lever the greater will be 

 its power. If the effort which the lever transmits exceeds 

 the endurance of its fulcrum (in this case the timber at 

 the lower edge of the ferrule), the latter will surely be 

 crushed, i. e., the rod will break at the ferrule. 



This simple principle of natural philosophy seems to 

 demonstrate that, other things being equal, the introduc- 

 tion of any ferrule weakens a rod, and that a longer fer- 

 rule weakens a rod more than a shorter; since with equal 

 pull at the tip, more strain is concentrated at the end of 

 a long ferrule (or lever) than at the end of a short fer- 

 rule (or lever). 



It is a corollary to this that in all jointed rods the 

 points where the ferrules terminate, are subject to a de- 

 gree of strain considerably in excess of the proportion 

 due to their location or in other words, in excess of the 



