196 



THE POPULAR SCIEXCE MOXTHLY 



The true curvature of the metal may be approximately deduced 

 from considering the radius of the circle described by the workman's 

 arms, aud the handle of the adze. 



The edge of the adze is convex (Fig. 12), the projection in the 

 middle being so formed for the same reasons as influenced the curva- 

 ture of the edtre of the axe already alluded to. 



The curvature in the blade also serves (though partially) as a ful- 

 crum, for, by slightly thrusting the handle from him, the -workman 

 mav release such flakes of timber as are over the adze, aud vet so 

 slightly adherent as not to require another blow. Thus the adze when 

 applied lever-fashion discharges its duty as the curvature in the claw 



ssfW^ 



Fig. 13. 



of a hammer does. Fig. 13 is a gouge-formed adze ; a modification 

 of this is used in making wooden spouts, and similar hollow work. 



Many of the remarks applied to axes and adzes also apply to pick- 

 axes. It may suffice to refer to two forms of this tool; they differ 

 not so much in the operative points as in the size and distribution of 

 the material. 



The one used by paviors is long and light, and of large curvature; 

 the other, used by stone-masons and quarrymen, is short-handled and 

 heavy, much material being concentrated in the head. There is also 

 another form of this instrument used on kegs, for the purpose of driv- 

 ing home the wooden wedges ; in this form there is no point, the tool 



Fig. 14. 



is rather that of an elongated hammer, the ends being provided with 

 " panes '* of different forms, set off at different angles. Snch tools may 

 properly be consigned to the class of hammers. 



The pavior's, the mason's, and the quarryman's picks are the tbree 

 to be very briefly considered. The first is properly a lever, and no 



