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THE POPULAR SCIENCE MONTHLY. 



progressive condensation of fibres, and to that extent an increase in 

 the difficulty of the work. 



The equally-inclined sides of the wedge-form of edge hitherto 

 alone described as belonging to axes, and the equal pressure this form 

 necessarily exerts upon each side if a blow is given in the plane of 

 the axe, suggest what will be the action of an axe if the angle of the 

 wedge is not bisected by the middle line of the metal. Assume that 

 one face only is inclined, and that the plane of the other is continu- 

 ous to the edge, then let the blow be struck as before. It will be 

 obvious that the plane in the line of the fibres cannot cause any sep- 

 aration of these fibres, but the slope entering the wood will separate 

 the fibres on its own side. Suppose a hatchet sharpened as pre- 

 viously described, and one as now described, are to be applied to 

 the same work viz., the cutting from a solid block the outside ir- 



Fig. 9. 



Fig. 10. 



regularities say to chop the projecting edges from a square log and 

 to prepare it for the lathe. It may be briefly stated that the hatchet 

 described in the second case would do the work with greater ease to 

 the workman, and with a higher finish, than the ordinary equally-in- 

 clined sides of the edtre of the common hatchet. Coach-makers have 



Fig. 11. 



much of this class of hatchet-paring work to do, and the tool they 

 use is shaped as in Fig. 10. The edge is beveled on one side only, 

 and, under where the handle enters the eye, may be noticed a piece 

 rising toward the handle ; on this the finger of the workman rests in 

 order to steady the blade in its entrance into the timber in the plane 





