of Bronzes from Machu Picchu, Peru. 591 



a stone or in a similar manner. It appears reasonable to con- 

 clude that this implement was used in heavy work, perhaps 

 upon stone, whereby the edge suffered severely and was 

 appropriately dressed from time to time. 



Object No. 11 (cf. Table I). 



Only the flattened head of the cloak pin illustrated in fig. 

 19 was examined. A number of hardness tests were made 

 on different parts of the surface after removing the outer 

 skin. Scleroscopic numbers varying from 14 to 18 were 

 obtained. This indicates that the metal was finished hard and 

 the recrystallized structure shown in the photo-micrograph, fig. 

 77, supplies additional information to the effect that inter- 

 mediate annealing treatment was applied in flattening the head. 

 Some undissolved tin-rich material (light centers with broad 

 black boundaries due to inequality of focus) is present. 

 Abundant lines of deformation, corresponding to the hard 

 finish, may be seen. 



The head of this object bears an aperture just above the 

 union with the shank, as shown in the diagram, fig. 76. This 

 aperture almost certainly existed before the head was flattened, 

 since it is now asymmetrically conical in shape, a condition 

 which may easily be duplicated by hammering over one face 

 of an ordinary cylindrical aperture. In an experiment of this 

 sort, the face held on the anvil remains open, while the ham- 

 mered face tends to close. Thus, the head of the present 

 object appears to have been hammered on one side only, viz., 

 the side opposite to that represented in fig. 76. In all prob- 

 ability, the aperture was originally provided in casting the 

 metal. 



Object No. 12 (cf. Table I). 



This object, illustrated in fig. 21, is a thin circular disc 

 slightly dished from rim to center and bearing a slotted handle. 

 Many objects of this sort have been found in Peru (the present 

 collection embraces several) and they are generally supposed 

 to have been used as mirrors. Baessler (1. c. 28) describes a 

 similar object containing about 9 per cent tin. The present 

 piece contains about 5.31 per cent tin and is distinctly inferior 

 in whiteness to alloys containing 9 or 10 per cent tin. It is 

 worthy of note that bronzes of this character, while capable of 

 high polish, would require frequent polishing to preserve a 

 highly reflecting surface as they tarnish readily. They are in 



