276 



THE GEOLOGIST. 



knives chipped off it lying close by, and fitting accurately into their places 



upon it. 



" Now to make the case complete, 

 we ought to find such prisms in 

 Mexico ; and accordingly, some 

 months ago, when I examined the 

 splendid Mexican collection of Mr, 

 Uhde, at Heidelberg, I found one 

 or two. No one seemed to have 

 suspected their real nature, and 

 they had been classed as maces, or 

 the handles of some kind of weapon. 

 I should say from memory that they 

 were seven or eight inches long, 

 and as large as one could conve- 

 niently grasp ; and one or both of 

 them, as if to remove all doubt as 

 to what they were, had the strip- 

 ping off of ribbons not carried quite 

 round them, but leaving an inter- 

 mediate strip rough. There is ano- 

 ther point about the obsidian knives 

 which requires confirmation. One 

 can often see on the ends of the 

 Scandinavian flint knives the bruise 

 made by the blow of the hard stone 

 with which they were knocked off. 

 I did not think of looking to this 

 point when at Mr. Uhde's museum, 

 but the only obsidian knife I have 

 seen since seems to be thus bruised 

 at the end. 



" Once able to break his obsidian straight, the workman has got on a long 

 way in his trade, for a large proportion of the articles he has to make are 

 formed by planes intersecting one another in various directions. But the 

 Mexican knives are generally not pointed, but turned up at the end, as one 

 may bend up a druggist's spatula. This peculiar shape is not given to answer 

 a purpose, but results from the natural fracture of the stone. 



" Even then, the way of making several implements or weapons is not 

 entirely clear. We got several obsidian maces or lance-heads — one about ten 

 inches long — which were taper from base to point, and covered with taper 

 (lutings; and there are other things which present great difficulties. I have 

 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. Such a process may have been used in 

 Mexico. 



We may see in museums beautiful little articles made in this intractable 

 material, such as the mirrors and masks I have mentioned, and even rings and 

 cups. But, as I have said, these are mere lapidaries' work. 



The situation of the mines was picturesque ; grand hills of porphyrinic rock, 

 and pinc-forest everywhere. Not far off is the broad track of a hurricane, 

 which had walked through it for miles, knocking the great trees down like 

 ninepins, and leaving them to rot there. The vegetation gave evident proof 

 of a m'\ ere climate ; and yet the heat and glare of ^the sun were more intolerable 



Fluted prism of obsi- 

 dian ; the core from 

 which flakes have 

 been struck off. 



Aztec knives or razors. 

 Long narrow flakes of 

 obsidian, having a sin- 

 gle face on one side, and 

 three facets on the other. 



