ON HOOKS. 17 



penetrate in its own direction ; while the latter, 

 which is at right angles to the upper surface 

 of the hook point, tends to tear it upwards and 

 out of the flesh ; but if the resistance is sufficiently 

 great, it will do little more than slightly " spring " 

 the wire and create extra friction. It will be 

 seen that a hook's penetrating power decreases as 

 the angle p increases, and increases with the ratio 

 of P X to P Y, or the ratio of the useful force to 

 the harmful. It is, of course, also affected by the 

 degree of sharpness and form of the point, and 

 by the prominence of the barb. 



In Mr. PennelFs diagrams the line of penetra- 

 tion is shown lying on the under surface of the 

 hook-point. Mr. Wells, in correcting this error, 

 goes to the other extreme, and asserts that the 

 upper surface in an ordinary hook " determines 

 its promptness to engage, as well as the direction 

 in which it will follow." The italics are mine. I 

 quote the following from "Fly Rods and Fly 

 Tackle " : 



" Take a common carpenter's chisel and apply it to a 

 board, with the bevel down and in contact with the 

 board. The bevel here guides the edge, and forces it to 

 advance parallel with the surface upon which the bevel 

 rests ; there is not the slightest tendency to bury. It 

 would seem to follow from this that the hook shown in 

 the first of Mr. Fennell' s figures (Fig. 6) is by no means 

 theoretically perfect as to penetration (or promptness 

 * to bite,' which is the idea I understand Mr. Pennell 

 intends to convey), but, on the contrary it is both 

 theoretically and practically imperfect in this respect. 



" Now let us reverse the chisel and apply it to the 

 board, with the bevelled side uppermost, and at such an 

 angle that the flat side (which will then become what 

 we have termed the ' following ' side), does not touch 

 the board. Here we have an exact reproduction of the 

 penetrating point of a fish hook, one governed by exactly 

 the same laws. Attempt to cut with the chisel held in 

 this position ! It buries at once in the board and comes 

 to a halt. The * advancing ' edge, the bevel, guides 

 and forces it downwards." 



