of Bronzes from Machu Picchu, Peru. 593 



others before the last annealing treatment, which, in view of 

 the residual inhomogeneity (shadowy cores and distinct traces 

 of the original tin-rich network), was of moderate intensity 

 (e. g., brief period, neighborhood of 750°). 



Object No. Ik (cf. Table I). 



There are a large number of thin, flat knives in the collec- 

 tion of the form illustrated in fig. 20. Eight of these, in 

 addition to the copper knife of similar form which has already 

 been described, were analyzed (cf. Table I) and one was 

 examined in the blade, shank and handle. As would be 

 expected, a structure indicative of severe working with asso- 

 ciated annealing was observed. The general conclusions drawn 

 from the examination of the present object should apply fairly 

 well in all cases. 



Two structures at the upper end of the object have been 

 chosen for reproduction. One of these, fig. 85, as may be seen 

 from the adjacent diagram of position, fig. 83, represents the 

 shank just before it bends around into the hook-shaped handle. 

 Here, as well as all along the shank and handle, the sulphide 

 constituent is threaded out to an extent indicative of at least 

 100 per cent elongation in the working of these parts. This 

 condition was very closely duplicated by cold-rolling a piece 

 of metal taken from Object "No. 8, which contains a large 

 quantity of normally equiaxed sulphide, so as to obtain an 

 extension of 1371/2 per cent (from 16 mm. to 38 mm.). After 

 extension to 35 mm. the piece was annealed by bringing it 

 momentarily to red heat. The final condition is shown in fig. 

 87. This surface was prepared so as to show the continuity 

 of the elongated sulphide particles as well as possible without 

 regard to the detail of the matrix. In preparing fig. 85, this 

 feature was not primarily considered and the smudgy appear- 

 ance of the lines is due to imperfect preparation in this respect. 

 The sulphide particles are, in reality, enormously extended 

 without apparent fracture. In the blade of the knife, the 

 particles of sulphide are small, numerous and often grouped, 

 but not distinctly elongated in any one direction. It thus 

 appears that the blade has been worked so as to extend the metal 

 more or less uniformly in several directions. Photo-micro- 

 graph, fig. 84, represents the structure passing from the inner 

 edge at the point of the bend towards the center. Very fine 

 recrystallized grain is observed at the edge where the original 

 grains were most severely overstrained in bending. Towards 



