One of the most curious aspects of the second clock produced by Father
Borghesi and Bertolla, as well as of the second published volume, is the
presence of chronograms which occur repeatedly on the clock dial and
throughout the _Novissimum Theorico-Practicum Astronomicum Authoma_ from
the title page to the end of the book. Interestingly enough, Father
Borghesi did not utilize this device even once in his first little book.
[Illustration: Figure 18.--A CHRONOGRAM in the text of Father Borghesi's
second volume, indicating the year 1764. The poem is translated as: "In
the Mount of 'Anáuni,' the inscrutable heavens are led, You learn from
these all the labors of the sun and the moon. Here you are shown and
hear the conjunction of the moon: And a bell brings to the ears by its
sound, all eclipses."]
Webster defines a chronogram as an inscription, sentence, or phrase in
which certain letters express a date or epoch. The method used by Father
Borghesi for forming chronograms was a simple one. He used combinations
of uppercase and lowercase letters in two sizes in the inscriptions on
the clock dial and in his writings. At first this curious combination in
the inscriptions on the dial plate was a source of considerable
speculation. The extremely fine quality of the engraving and artistry
was such that these combinations could only be deliberate in nature and
not the accidental whims or accidents of the engraver. Accordingly, they
must be chronographic in intention. Such proved to be the case.
Borghesi used the larger size of uppercase letters to form the
chronogram, and each chronogram was complete within a phrase or line. He
accomplished this by using for this purpose those letters of the
alphabet which form the Roman numerals. The uppercase letters found
within words are copied off in the order in which they appear in the
inscription or phrase. These are then converted into their numerical
equivalents, and totaled. Taking the uppermost inscription on the clock
dial as the first example: