or of iron in the fire." Hernandez[1] gives a similar account of the process, but compares the wooden instrument used to a cross-bow, so that it would appear to have had a crutch-shaped end to rest against the breast. So skilful were the Mexicans in the manufacture of obsidian knives, that, according to Clavigero, a single workman could produce a hundred per hour.
The short piece of heavy wood was probably cut from some of the very hard trees of tropical growth. I much doubt whether any of our indigenous trees produce wood sufficiently hard to be used for splintering obsidian; and flint is, I believe, tougher and still more difficult of fracture. We have, however, in this Mexican case, an instance of the manufacture of flakes by sudden pressure, and of the employment of a flaking tool, which could be carefully adjusted into position before the pressure or blow was given to produce the flake.
Mr. G. E. Sellers, in the Smithsonian Report for 1885,[2] has published some interesting "observations on stone chipping," and from the report of Mr. Catlin, who sojourned long among the Indians of North America, gives sketches of crutch-like flaking tools tipped with walrus tooth or bone which he had seen in use. He also describes a method of making flint flakes by the pressure of a lever. The whole memoir is worthy of study.
The subject of the manufacture of stone implements is also discussed by[3] Sir Daniel Wilson in an essay on the Trade and Commerce of the Stone Age.
There appears to have been another process in use in Central America, for Mr. Tylor[4] heard on good authority that somewhere in Peru the Indians still have a way of working obsidian by laying a bone wedge on the surface of a piece and tapping it till the stone cracks. Catlin[5] also describes the method of making flint arrow-heads among the Apaches in Mexico as being of the same character. After breaking a boulder of flint by means of a hammer formed of a rounded pebble of horn-stone set in a handle made of a twisted withe, flakes are struck off, and these are wrought into shape while held on the palm of the left hand, by means of a punch made of the tooth of the sperm whale, held in the right hand, and struck with a hard wooden mallet by an assistant. Both holder and striker sing, and the strokes of the