Two attachments, in the form of small superimposed dials are situated at
the base of the dial plate, at either side and immediately below the
fourth chapter ring. In his second volume, Father Borghesi stated that
they "are not moved from inside the clock, but the one at the right
[inscribed _concitat_ and _retardat_] serves for loosening
[accelerating] and tightening [retarding] time; that is, the reins of
the perpendicular."
In other words, the purpose of this attachment is for adjusting the
pendulum to make the clock operate fast or slow. The second attachment,
which appears at the left, and which is inscribed "Claudit" (close) and
"Aperit" (open) serves the purpose of "... preparing the mechanism in a
moment, as swiftly as you wish, for sustaining the astronomical
experiments of which you will hear later; when these things have been
done, it restores the mechanism to its natural motion at the same
speed."
This adjustment relates to the final section of Father Borghesi's second
book, entitled "Chronologo-Astronomicus Usus Authomatis"
(Chronological-Astronomical Use of the Automaton), which is translated
from the Latin in its entirety:
With one glance at this automaton, you can quickly answer these
questions: What hour the sun shows, the moon, any fixed star,
the head and tail of the dragon. Is the sea swelling with
periodic heat [at high tide?] or is it deflated [low tide], or
quiescent? How many days is it from mean new moon or full moon?
By how many signs and degrees is the moon distant from the sun,
and from its nodes? What sign of the zodiac does the sun
occupy, the moon, the head and tail of the dragon? Is the sun
or the moon, in apogee or perigee, ascending or descending?
What is the apparent speed of the sun and of the moon? What is
the apparent magnitude of the solar and lunar diameter, and of
the horizontal parallax of the umbra and penumbra of the earth?
What is the latitude of the moon? Is it north or south? Does
the moon hide [occult eclipse] any of the fixed stars from the
earth dwellers, and which of these does it obscure? Is there a
true new or full moon? Is the sun in eclipse anywhere on earth?
What is the magnitude, and the duration of this eclipse, with
respect to the whole earth? Can it be seen in the north or in
the south? Is the moon in eclipse? Total or partial? Of what
magnitude, etc.? What limb of the moon is obscured? How many
years have passed from a given epoch? Is this year a leap year,
or a common year--first, second, or third after leap year? What
is the current month of the year, and what day of the month and
of the week? Which of the planets is dominant? What days of the
year do the various feasts fall on, and the movable feasts
during the ecclesiastical year? And many other similar
questions, which I pass over here for the sake of brevity.
Besides, this device can be so arranged for any time
whatsoever, past or future, and for the longitude of any
region, and can be so manipulated by hand, that within the
space of a very short time there can be provided in their
proper order, the various orbits of the luminous bodies, their
alternating eclipses, as many as have taken place through the
course of many years, or even from the beginning of the world;
or those that will be seen as long as the world itself shall
last, with all their attendant circumstances (year, month, day,
duration, magnitude, etc.). All these can be seen with great
satisfaction of curiosity and of learning, and hence with great
pleasure to the soul. In the meanwhile, the little bells
continually play, at their proper, respective times. So that,
all exaggeration aside, a thousand years pass, in the sight of
this clock, as one day!
I am aware of your complaints, O star-loving reader--that my
description is too meager and too succinct. Lay the blame for
this on those cares, hateful both to me and to you, more
pressing, which forbid me and deprive you of a methodical
explanation of the work.