594 C. H. Mathewson — MetallograpMc Description 



the center, where the minimum strain was felt, the original 

 coarser grain is relatively little altered. These conditions 

 would be produced by suitably annealing a bend formed in 

 soft metal of the structural characteristics shown in fig. 85 and 

 they indicate that the piece received annealing treatment after 

 the handle was bent into shape. Scleroscopic tests on this 

 object show hardness numbers of about 14 on the shank and 

 27 on the thin parts of the blade, which was set in plaster for 

 these tests. Thus, there is considerable temper in the blade 

 and some in the shank (soft, annealed alloys of this composition 

 give hardness numbers below 10). 



It may be said, in conclusion, that nothing can be learned 

 from this examination relative to the original size and shape 

 of the casting from which the knife was made. Several knives 

 may have been made from one cast piece although there is no 

 particular reason for believing this to be true. In any event, 

 the casting structure is totally obliterated and the piece in its 

 present condition cannot bear much resemblance to original 

 stock used in its construction. 



Object No. 15 (cf. Table I). 



Only a small piece from the axe illustrated in fig. 23 was 

 examined. This was cut from the extremity of one of the arms 

 or branches forming the head, as shown in the diagram, fig. 

 88. The corresponding photo-micrograph is shown in fig. 89. 

 Its comparatively fine grain (counting 28) indicates final 

 annealing treatment hardly above dull red heat unless extremely 

 brief, and the presence of faint cores indicates that the object 

 has never been held at a temperature corresponding to bright 

 redness for any considerable period of time. Deformational 

 characteristics are present and the axe has been left in the 

 hammer-hardened condition. 



Object No. 16 (cf. Table I). 



The object illustrated in fig. 24 appears to be a chisel which 

 has been broken off about 2%" above the edge and twisted so 

 that vertical planes passing through the edge and the opposite 

 end, respectively, would intersect at an angle of about 12°. 

 One of the vertical edges of the chisel was ground down fiat, 

 polished, etched, and examined along its entire length. A 

 diagram of this surface is given in fig. 90. At 72 X, the finer 

 detail of the structure is imperfect owing to the small size of 

 the recrystallized grains and the presence of prominent primary 



