There is a discrepancy between Father Borghesi's written description in
his second book of the number of bells and those which currently exist
in the clock. At the present time, there are two sets of bells attached
to the upper part of the movement. While Father Borghesi indicated that
there were two sets of bells in the clock, he described the first set by
stating that:
... there are three bells inside the clock: The largest, when
struck by a little hammer at each mean new moon, signifies the
new moon. The smallest indicates in the same way the full moon
at the time of the mean full moon, by automatic sound. When on
the equatorial earth, the sun appears anywhere in eclipse, two
bells (the largest and the medium) sounding together
automatically, announce that eclipse at the time of the mean
new moon. (I think it is evident that eclipses of the sun occur
at new moons and eclipses of the moon at full moon.)
When the moon is eclipsed, the smallest and the medium bells,
simultaneously and automatically, announce the event to the ear
at the time of the mean full moon. Besides, at the proper time
and automatically, the largest of these bells announces the
current solar hour and the smallest bell strikes the quarter
hours.
In the clock today, the first set consists of a smaller bell fixed
within a larger one. It is presumably these bells that indicate the
eclipses and also strike the hours and quarter hours. A pull cord
attached to the striking mechanism repeats the current hour and quarter
hours at will. The second set consists of nine meshed bells struck with
individual hammers operated by means of a pinned cylinder as in a music
box. On the hour, the chimes play one of two melodies, which may be
changed at will. While not identified, these appear to be Tyrolean folk
melodies. The largest of this set of bells is dissimilar to the other
chimes, and may be the third bell described by Father Borghesi to
signify the new moon.