been transported thirty miles by Mexican labourers, for
the stone is not found nearer than that distance from the city; and
this transportation was, of course, managed by hand-labour alone, as
there were no beasts of burden.

We know pretty well the whole system of Mexican astronomy from this
calendar-stone and a few manuscripts which still exist, and from the
information given in the work of Gama the astronomer and other writers.
The Aztecs and Tezcucans who used it, did not claim its invention as
their own, but said they had received it from the Toltecs, their
predecessors. The year consisted of 365 days, with an intercalation of
13 days for each cycle of 52 years, which brought it to the same length
as the Julian year of 365 days 6 hours. The theory of Gama, that the
intercalation was still more exact, namely, 12-1/2 days instead of 13,
seems to be erroneous.

Our reckoning only became more exact than this when we adopted the
Gregorian calendar in 1752, and the people marched about the streets in
procession, crying "Give us back our eleven days!" Perhaps this is not
quite a fair way of putting the case, however, for the new style would
have been adopted in our country long before, had it not been a Romish
institution. It was the deliberate opinion of the English, as of people
in other Protestant countries, that it was much better to have the
almanack a few days wrong than to adopt a Popish innovation. One often
hears of the Papal Bull which settles the question of the earth's
standing still. The history of the Gregorian calendar is not a bad
set-off against it on the other side. At any rate, the new style was
not introduced anywhere until sixty or seventy years after the
discovery of Mexico, and five hundred years after the introduction of
the Toltec calendar in Mexico.

The Mexican calendar-stone should be photographed on a large scale, and
studied yet more carefully than it has been, for only a part of the
divided circles which surround it have been explained. It should be
photographed, because, to my certain knowledge, Mayer's drawing gives
the year, above the figure of the sun which indicates the date of the
calendar, quite wrongly; and yet, presuming on his own accuracy, he
accuses another writer of leaving out the hieroglyph of the winter
solstice. What is much more strange is, that Humboldt's drawing in the
small edition of the _Vues des Cordilleres_ is wrong in both points.
The drawing in Nebel's great wor