In this part of Mexico Captain Dupaix examined a peculiar ruin, of which
he gave the following account: "Near the road from the village of
Tlalmanalco to that called Mecamecan, about three miles east of the
latter, there is an isolated granite rock, which was artificially
formed into a kind of pyramid with six hewn steps facing the east. The
summit of this structure is a platform, or horizontal plane, well
adapted to observation of the stars on every side of the hemisphere. It
is almost demonstrable that this very ancient monument was exclusively
devoted to astronomical observations, for on the south side of the rock
are sculptured several hieroglyphical figures having relation to
astronomy. The most striking figure in the group is that of a man in
profile, standing erect, and directing his view to the rising stars in
the sky. He holds to his eye a tube or optical instrument. Below his
feet is a frieze divided into six compartments, with as many celestial
signs carved on its surface." It has been already stated that
finely-wrought "telescopic tubes" have been found among remains of the
Mound-Builders. They were used, it seems, by the ancient people of
Mexico and Central America, and they were known also in ancient Peru,
where a silver figure of a man in the act of using such a tube has been
discovered in one of the old tombs.