ed even more than the above title, for there is a Nahuatl noun
tlachiuhtli, which means, "something made or formed or engendered," or
"earth which is ploughed and sown." Then there is the verb tlachipaua
which means, "the smile of dawn, the break of day, the clearing up of the
weather," also the purification and cleansing, all of which were supposed
to be under the dominion of the rain-god and of his living representatives
on earth, the rain-priests. The seemingly conflicting fact that the
tlachieloni sceptre was also assigned to the god of fire is explained by
the existence of the verb tiachinoa=to burn up the fields or forests, and
of the noun tlachi-noliztli=the act of burning up or scorching the fields
or forests, and finally, metaphorically, tlachinoli-teuotl=war or
battle=destruction. It is only when we thus realize all the natives could
express by the image of an eye, looking through a circle, that we begin to
grasp its full meaning when employed as a symbol in their picture
writings.

As to the obsidian mirror, which undoubtedly was the symbol of
Tezcatlipoca and, consequently, must have pertained to his representative,
the priest of the Night, we find that it played a most prominent role in
the cult he presided over. In the first case it appears as though it was
resorted to in Mexico as in the conquered province of Guatemala, as the
oracle which rendered final judgment. A series of illustrations, etc., to
be published in my final work on the Calendar System, will prove
satisfactorily that the Mexican astronomers extensively employed black
obsidian mirrors as an aid to astronomical observations, by means of
reflection. Besides mirrors on the summits of temples and mountains,
certain square columns, placed on an elevation and faced with a broad band
of polished obsidian, are pictured in some Codices. It is obvious that the
latter in particular, if carefully oriented, would have served as an
admirable means of registering the periodical return of planets, stars or
constellations to certain positions; they would then be reflected on the
polished surface, as in a frame. In certain Codices the double, tau-shaped
courtyard or enclosure surrounded by a high wall with battlements, which
was employed in the daytime for the national game of ball, figures in
combination with obsidian mirrors. I draw attention to the fact that the
name of these courtyards was tlach-tli, which literally means the looking
place=the observatory