Leaders. 119 



"upset" when tightened that is, the knot must be on 

 the loop of the leader itself, and by no means on the 

 line, since in the one case it will stand, and in the other 

 it will not. This will be more clear if we investigate 

 the principle on which it is constructed. On examining 

 the diagram, it appears that the end of the line is 

 first run through the loop of the leader, then wrapped 

 entirely around the outside of the loop, and lastly is 

 tucked between the line on one side and both parts of 

 the loop on the other. Clearly this knot cannot slip, un- 

 less the end of the line slips at the same time. But the 

 greater the strain, the more firmly that end is compressed 

 and held ; while if the knot is pushed down the loop of 

 the leader, as shown in the first figure, it is clear that 

 the end is at once freed from pressure, and may be easily 

 withdrawn and the knot released. To facilitate this, 

 some double the end before putting it under the line, as 

 shown in the second figure. Then a pull on the end 

 loosens the knot, just as a shoe is untied. If, however, 

 the knot is allowed to " upset," this is the result, in which 

 it is clear, first, that the end of the line is not " jammed," 

 and second, that the knot cannot easily be unfastened. 



Pig. 28. 4, line; B, leader. 



If not already familiar with this knot, try it right here 

 with a piece of string. It is very simple. Half a dozen 

 experiments, guided by the diagram, will indelibly im- 

 press it on the memory. No person learns a knot solely 



