Besides the larger and smaller indices already mentioned, all [of which]
revolve within the periphery of the three largest circles, six dials in
this clock also revolve within the same circles which are to be seen
through six openings of the frontispiece. The first of these, intended
to indicate the phases of the moon by an unusual method (completely
black, and decorated with the characters of the principal aspects of the
moon) continually revolves interiorly around the center of the machine
and at the new moon, it completely removes from sight the face of the
moon through the round window. It continually recedes through the first
half of the circle until, at the time of the full moon, it restores the
moon, looking out with a full star. Soon again, too slow to be
observed, it returns through the other half of the circle, so that in
the next conjunction, the whole face of the moon may have a covering of
darkness, once again to be removed.
The other dials are moved by spontaneous advances at stated times. The
first of these shows, through a square opening, the day of the month;
the second, through another opening, shows the current day of the week
with the characters of the seven planets which, according to ancient
superstition, preside over each day of the week (now, by a truer form of
religion divided by the Church into ferias, etc.); that is, the sun, the
moon, Mars, Mercury, Jupiter, Venus and Saturn, to which I have added
the numbers of the ferias. These two little dials are advanced daily, by
a sudden movement at midnight. The remaining three are changed
automatically only once a year on the first of January.
The first of these dials contains five little cells, opening from a
common window: in the first cell, at the edge of the dial, is found the
dominical letter; in the second, the cycle of the sun; in the third, the
character; in the fourth, the sign; and, in the fifth, the house of the
planet dominating the year. The second dial shows the epacts, with the
golden number. The third, and last of all, shows the Roman cycle.
Finally, as indicated by the epact and the dominical letter in an
immovable table added outside, are the feastdays and other movable
events of the year; that is, Easter, the four seasons, the Rogation
Days, etc.