AKT. a. HISTORY OF INVENTIONS HOUGH. 33 



PKIMITIVE METAL WORKING. 



Plate 32. 



Navaho Indians making silver ornannents. — The Navaho Indians 

 of Arizona and New Mexico were taught a rude sort of metal work- 

 ing by the Spanish conquerors, and they have become very adept in 

 the use of their primitive tools and apparatus. It is not known that 

 they mined for silver, all of their products being made from Mexican 

 and American coins. The silver is either cold hammered or melted 

 in open crucibles by the use of charcoal and flux, with blast produced 

 by bellows having two air sacks of leather, as crude as those of the 

 Congo Negroes. Much metal is wasted in the operation. It is 

 brought into final shape by hammering, punching, chasing, and en- 

 graving. The objects made are mainly personal ornaments, such as 

 buttons, ear ornaments, beads, and bracelets. Examples are placed 

 with the figures. 



SERIES 1. — REDUCTION IN METAL WORKING. 



Plate 33. 



By this phrase is meant those arts that are practiced upon metals 

 in order to prepare them for the manufacture of useful things. 



This series begins with those metallic ores which were treated by 

 the lower races after their manner of stoneworlring, for paint, for 

 simple tools, or for ornaments. The next steps in these primitive 

 processes are the cold hammering of ores, the forging of rich ores, 

 smelting, casting, riveting, welding, alloying, and soldering. In 

 each case a bettering of tools and a complication of wants would go 

 hand in hand. 



Xo. 1. Nuggets of iron ore, slightly modified, from the mounds of Kentucky. 

 No. 2. Pieces of iron ore modified by flaking and rubbing to form the blades of 



common tools. Mounds of the Mississippi Valley, 



90,733, 19,601. 62,024 

 No. 3. Pieces of iron ore polished. Mounds of the Mississippi Valley, 



34,652, 34,521 

 No. 4. Pieces of crude copper ore cold hammered into shape. Lake Superior 



re^on 1,136, 31,937 



No. 5. Ck)pp€r cold hammered into sheet and arrowhead. Mounds of Ohio and 



Michigan 10,213, 113,738 



No. 6. Sheets of copper cold hammered into shape and perforated. Embossed 



by punching. Mounds of Wisconsin 88,387, 90,737 



No. 7. Sheet of copper crimped and corrugated by hammering. Mounds and 



Northwest coast 61,174, 67,947 



No. 8. Copper cast into form of ancient half-socketed ax or adz. Wisconsin. 

 No. 9. Bronze hatcliet blades from Europe. Casts showing the steps in the art 



of socketing 140,721, 101,109. 10,116 



No. 10. Cast-iron fish, showing the latest results of fine casting 95,021 



