ry key to assist us in deciphering them makes
it exceedingly difficult to decide how far this change had progressed. We
are therefore left wholly to deductions to be drawn from the facts
obtained by laborious comparisons of the various relations in which the
characters are found and the uses which appear to be made of them in the
manuscript.

It will be admitted without question that a large number of these
characters are ideographs or conventional symbols, as distinguished from
pictures, as, for example, most of those denoting the days, months, and
cardinal points. I say most of these, as it is yet possible to learn from
some of them the objects they were intended to represent, the
characteristic features not being entirely lost, as the symbol for the
day Cimi, the "death's head" or skull; that of the day Ymix, "the grain
of maize;" that of the month Moan, "the head of the moo or ara," a
species of parrot, &c.

It is also possible to show from the manuscripts themselves evidences of
the changes from conventional pictographs to true or mnemonic symbols.

Take, for instance, the bird symbols on Plates 16, 17, and 18 of the
Dresden Codex, presented in the preceding marginal figures numbered 24,
25, 26, 27, 28, and 33. If the determination be correct as given, it is
apparent that, while one of the birds is indicated by the head as a
symbol, the others are denoted by ideographs, or by phonetic characters
bearing no resemblance to their forms or peculiar features. That numerous
examples of this kind are to be found in these manuscripts will be
admitted by all who have carefully studied them.

Another fact bearing upon this point is the difference between the
Dresden Codex and the Manuscript Troano in regard to marking with symbols
the things represented in the pictures. We fail to find in the former
(unless that on Plate 30 be a possible exception) the earth or soil
represented by any symbol, though frequently occurring in the latter and
also occasionally in the Cortesian Codex. The symbol for wood or that
appearing so often on wooden articles in the latter, and occasionally in
the Cortesian Codex, is wanting in the Dresden Codex, though wooden
articles are several times represented. From this we infer that the
Manuscript Troano is a more recent production than the Dresden Codex,
notwithstanding the evidences of greater skill in drawing and higher
mathematical attainments shown in the latter.

Before discussing the ques