ed with
carvings. It is remarkable that, though the altars for human sacrifices
are no longer to be found, these accessory stone clamps, or yoke-like
collars, are not uncommon. A fine one from Mr. Christy's collection is
figured. _(See opposite page.)_

The obsidian knives and arrow-heads are very good, but these I have
spoken of already, as well as of the stone hammers. The axes and
chisels of stone are so exactly like those found in Europe that it is
quite impossible to distinguish them. The bronze hatchet-blades are
thin and flat, slightly thickened at the sides to give them strength,
and mostly of a very peculiar shape, something like a T, but still more
resembling the section of a mushroom cut vertically through the middle
of the stalk.

The obsidian mask is an extraordinary piece of work, considering the
difficulty of cutting such a material. It was chipped into a rude
outline, and finished into its exact shape by polishing down with
jeweller's sand. The polish is perfect, and there is hardly a scratch
upon it. At least one of the old Spanish writers on Mexico gives the
details of the process of cutting precious stones and polishing them
with _teoxalli_ or "god's sand." Masks in stone, wood, and terra-cotta
are to be seen in considerable number in museums of Mexican
antiquities. Their use is explained by passages in the old Mexican
writers, who mention that it was customary to mask the idols on the
occasion of the king being sick, or of any other public calamity; and
that men and women wore masks in some of the religious ceremonies. A
fine mask of brown lava (from Mr. Christy's collection), which has been
coloured, is here figured. _(See illustration.)_ The mirrors of
obsidian have the same beautifully polished surface as the obsidian
mask shows; and those made of nodules of pyrites, cut and polished, are
worth notice.

The Mexicans were very skilful in making pottery; and of course there
is a good collection here of terra-cotta vases, little altars and
incense-dishes, rattles, flageolets, and whistles, tobacco-pipes and
masks. Some of the large vases, which were formerly filled with skulls
and bones, are admirable in their designs and decorations; and many
specimens are to be seen of the red and black ware of Cholula, which
was famous at the time of the Conquest, and was sent to all parts of
the country. The art of glazing pottery seems only to have been
introduced by the Spaniards, and to this day the Indian