Fish-hooks. 19 



line, as shown by our former experiment ; J5 C will then 

 represent the " draft-line." That side of the barb marked 

 a I have termed the "inner" or "advancing side;" that 

 marked d is intended when the " outer " or " following " 

 side is mentioned. 



It is hoped that the form of this diagram and the no- 

 menclature of its parts will be well fixed in the mind, 

 since then what follows will be easily understood. 



Fig. 5. 



It will be noticed that Mr. Pennell has determined 

 the penetrating angle from the outer line' of the barb. 

 I cannot but think this an oversight on his part, and one 

 which affects his results. It is not the "following " (d) 

 but the "advancing" side (a) of such a cutting edge or 

 penetrating point which determines its promptness to en- 

 gage, as well as the direction which it will follow. 



I say such a penetrating point, for if the " following " 

 side (d) of the point or edge is in actual contact with the 

 surface to be penetrated (as shown in Mr. PennelPs first 

 figure, page 14), it guides the edge in its own direction, 

 since that is the line of least resistance. It is clear that 

 this is not the case with a fish-hook, since there the " fol- 

 lowing edge (d) is raised above, and is not in contact 

 with the surface to be penetrated. 



But an illustration familiar to all will serve to make 

 this clearer than pages of theory. 



Take the common carpenter's chisel, and apply it to a 



