The section of a gun-flint, with its
one side flat for sharpness and the other side ribbed for strength, is
one of the characteristics of obsidian knives. That the flint knives of
Scandinavia were made by chipping off strips from a mass is proved by
the many-sided prisms occasionally found there, and particularly by
that one which was discovered just where it had been worked, with the
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.

[Illustration: FLUTED PRISM OF OBSIDIAN: THE CORE FROM WHICH FLAKES
HAVE BEEN STRUCK OFF.]

I should say from memory that they were seven or eight inches long, and
as large as one could conveniently grasp; and one or both of them, as
if to remove all doubt as to what they were, had the stripping off of
ribbons not carried quite round them, but leaving an intermediate strip
rough. There is another 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.

[Illustration: AZTEC KNIVES OR RAZORS. LONG NARROW FLAKES OF OBSIDIAN,
HAVING A SINGLE FACE ON THE ONE SIDE AND THREE FACETS ON THE OTHER.]

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 flutings; and there are other things which present great
difficulties. I have heard on good authori