Chapter III: Appendix: 71

BIBLIOGRAPHY 76

_Silvio A. Bedini_

_The Borghesi Astronomical Clock_
_In the Museum of History and Technology_

_The history of the 18th-century Borghesi astronomical clock is
described here from contemporary source material. The evolution
of its design by Father Francesco Borghesi and the building of
the complex mechanism devised by the clockmaker, Bartolomeo
Antonio Bertolla, is a story of the vision of one man turned
into reality by another. The result of their collaboration is
the unique, astronomical timepiece now in the Museum of History
and Technology._

THE AUTHOR: _Silvio A. Bedini is curator of mechanical and
civil engineering in the Smithsonian Institution's Museum of
History and Technology._

"... All this work I had performed eagerly, so that, while in
my room, I might contemplate leisurely, both during the day and
in the night, the true face of the heavens and of the seas
unobscured by clouds, even though I had no astronomical
equipment."[1]

With these words, Father Francesco Borghesi (1723-1802) of Mechel described the reasons which inspired him to invent a unique astronomical clock which is now in the horological collection of the Museum of History and Technology.

This complicated mechanism, which performs a multitude of functions, was designed by Father Francesco Borghesi, a secular priest in Venezia Tridentina. It was constructed in 1764 under his direction by a provincial clockmaker named Bartolomeo Antonio Bertolla (1702-1789) of Mocenigo di Rumo. It was the second of two complicated astronomical clocks which Father Borghesi designed and which Bertolla constructed. According to contemporary sources, this clock was presented to the Empress Maria Theresa of Austria soon after its completion.

Its history is rather hazy, except for the fact that in 1780 this second Borghesi timepiece was still in the Imperial Palace in Vienna. The clock was again noted in 1927 when it was sold at a public auction in New York.[2] Subsequently, it was acquired for the Smithsonian Institution.

Development of Astronomical Clocks

The history of the great theoretical and mechanical achievement which the Borghesi clock represents has been most adequately covered elsewhere.[3] Consideration of the development of equation and astronomical clocks is required here only for the purpose of relating the Borghesi timepiece with the other significant developments in this branch of horology.

The invention of the anchor escapement in about 1670, and the consequent greater accuracy in time-telling, led to increased preoccupation with precision. Daily differences in time as recorded by sundials and clocks became more noticeable. Finally, in the second half of the 17th century, some attempt was made to construct mechanical clocks combined with sundials as well as astronomical clocks.

With the improvement of precision time-telling, it became necessary to reconcile the actual difference between true and mean time. Although a great variety of time-equation tables were produced, there was a considerable margin for error in their use. This led to the construction of mechanical clocks in which the equation of time was automatically accomplished. A few were produced late in the 17th and early 18th century at considerable cost and, consequently, with little popularity. Equation sundials were also developed which were elaborately ingenious, but they were not completely practical. Inevitably, they were supplanted by the mechanical equation clock.

Probably the first documented mention of an equation clock is in the diary of John Evelyn who recorded that in 1666 he visited the Royal Society where he witnessed a curious clock, which showed the equation of time, being presented by a certain Mercator. More data on the subject appeared in the first two decades of the 18th century, when Henry Sully, Joseph Williamson, Daniel Quare, and Thomas Tompion--who were among the foremost English clockmakers of all time--produced elaborate examples of these timepieces. Another significant maker was Dowe Williamson, who became Court Clockmaker to Emperor Charles VI of Austria. In London, Joseph Williamson produced some of the finest astronomical timepieces of this type that have been known. The interest in the subject next shifted to France where many fine examples were produced during the first half of the 18th century.

Just after the middle of the 18th century, the subject of astronomical clocks suddenly became a major horological preoccupation in another region, namely, Austria, where the work in this field was apparently done exclusively by members of the clergy. The earliest was Father Philipp Matthäus Hahn (1739-1790) of Württemberg.[4] Father Hahn considered the equation of time as only one part of a plan to represent astronomical occurrences by means of clockwork. In addition to planetaria and similar mechanisms, Father Hahn produced two extraordinary astronomical, tall-case clocks, both of which survive in public museums.

* * * * *

ACKNOWLEDGMENTS

The author wishes to acknowledge the valuable assistance received from the following: DR. AMOS AVERY, Amherst, Massachusetts; MR. EDWIN A. BATTISON, curator of light machinery and horology, U.S. National Museum; DOTT. RICHARD BLAAS, Oesterreiches Staatsarchiv, Vienna; DOTT. ADOLFO CETTO, librarian, Biblioteca Comunale di Trento, who made copies of Borghesi's two volumes available; SIGNOR MARIO DI MARIO, editor of _La Clessidra_, Rome, who permitted several of the illustrations in Sig. Luigi Pippa's article to be used herein; MR. WALTER A. GILBERT, Norwich, Connecticut; DR. HEINRICH LINARDI, Uhrenmuseum der Stadt Wien, Vienna; SIGNOR LUIGI PIPPA, Milan, Italy; CAV. ING. GUIDO UCELLI DI NEMI, Presidente, and DOTT. FEDERICO MORELLI and CAV. ORAZIO CURTI of the Museo Nazionale della Scienza e della Tecnica, Milan, for their cooperation on the descriptions and illustrations of the restored clockshop of Bartolomeo Antonio Bertolla; and DR. EDWARD WATERS, Division of Music, Library of Congress, Washington, D.C.

The translation from Francesco Borghesi's Latin texts, which made this study possible, were made by: REV. NEIL HERLIHY, S.J., REV. FRANCIS J. HEYDEN, S.J., and REV. STEPHEN X. WINTERS, S.J., Georgetown University, Washington, D.C.; and REV. DANIEL HUNTER, O.P., and REV. ROBERT STENGER, O.P., Dominican House of Studies, Washington, D.C.

* * * * *

Another of the clerical clockmakers was Father Aurelianus à San Daniele (1728-1782), an Augustine monk in the monastery of the Imperial Court at Vienna.[5] His four complicated astronomical clocks, which exist in museums at present, are comparable to those produced by Father Hahn. The third cleric was Brother David à San Cajetano (1736-1796) in the same Augustine order to which Father Aurelianus belonged. He achieved note as the author of various publications, including _Neue Rädergebäude_[6] [New Construction of Wheels] relating to planet-wheels, or gear-trains containing epicyclic elements. He constructed a clock based on an elaborate astronomical design which was substantially different from the others. The fourth of the ecclesiasts who designed astronomical clocks in this period was Father Klein of Prague, who produced a complicated astronomical timepiece in about 1738.

The fact that such important and outstanding examples of astronomical clocks were produced exclusively by ecclesiasts in Austria during the second half of the 18th century is especially significant. It is particularly so when a fifth cleric is added to the group, also an Austrian subject although Italian by heritage, in the person of Father Francesco Borghesi.

Although only Father Borghesi's second astronomical clock is now known, it is apparent that this example in the Museum of History and Technology represents an experiment in astronomical time-telling comparable to any of the timepieces produced by Father Hahn, Father Aurelianus, Brother David à San Cajetano or Father Klein.

This combination of five clerical clockmakers who lived in the same region during the same period of time is sufficiently unusual. However, the fact that each of them apparently worked without association with any of the others leads to the conjecture that a common factor must have led them to their individual preoccupation with astronomical horology. What the link may have been is not apparent from the surviving records of the lives and works of these clerics. Certainly it was not an interest in astronomy or clockmaking per se, because other than the astronomical clocks, none of these horological inventors--with the possible exception of Father Hahn--worked in any other aspect of the fields of astronomy or horology. However, after a comprehensive study of Father Borghesi's writings, there is little doubt of the religious basis of his own inspiration.

Designer Borghesi

Father Borghesi's story takes place in the picturesque mountainous region of what was then known as Venezia Tridentina (since 1947, Trentino-Alto Adige) in northern Italy, along the Tyrolean border of Austria. Because of its strategic position as the passage between Innsbruck and Verona, the possession of the Tridentina was contested again and again in the European wars, but during Father Borghesi's lifetime, the Tridentina was under Austrian domination.

Deep within this mountainous district is the romantic valley of the Non, or Anáuni, with its great forests and ancient castles. Most maps do not mark it, and the tourist guides ignore it.[7] One of the chief communities is Cles, with its historic Renaissance buildings. The major city of the region is Trent on the Adige River, with its surviving Roman relics and Romanesque and Renaissance architecture.

The little villages scattered throughout the valley of the Non played no part in history, but such names as Mechel and Mocenigo di Rumo reflect the interchange of sovereignty. It was in the little village of Mechel that Francesco Borghesi was born in 1723.[8] Local records are meager and inadequate, and many of the details of Borghesi's life must be assumed. Inasmuch as the village was in a rural, agricultural district, Borghesi may have come from a family of farmers, vintners, or village tradesmen. Borghesi sought an education by entering the priesthood and was ordained a secular priest in Salzburg. He was first assigned as curate to the village parish of Rumo in the valley of the Non, a short distance from his birthplace.[9] Later, he was transferred to his native Mechel. He was inherently a man of simple tastes and of great piety. He tended to the needs of his mountain villagers and attended the births, weddings and deaths of his parishioners. It was during his assignment in this tiny community that Father Borghesi met and became friendly with the clockmaker, Bartolomeo Antonio Bertolla of nearby Mocenigo di Rumo.

Clockmaker Bertolla

Bartolomeo Antonio Bertolla was born in Mocenigo di Rumo, a short distance from Mechel, in 1702.[10] Nothing is known of his boyhood, other than the fact that he was mechanically inclined. At the age of 17 he was apprenticed to become a clockmaker with the master, Johann Georg Butzjäger of Neulengbach, a small village on the edge of the great Vienna woods.[11] This region was then part of the domain of the Archduke of Austria, of which Sankt Pölten was the capital.

Celebrated Mechanician and Inventor of various Instruments. Repairer of the clocks of Venice, Verona, Trent, and other localities. Maker of the Work which combines the Copernican and Ptolemaic Systems devised by Father Francesco Borghesi of Mechel, Laureate Mathematician, and humbly offered to Her Imperial Majesty Maria Theresa. Died in piety in his home at Rumo on 15 January 1789 at the age of 86." (_Courtesy of Sig. Luigi Pippa of Milan._)]

Bertolla began his apprenticeship with Butzjäger under the auspices of the Corporation of Blacksmiths of Sankt Pölten in 1719. His training was supervised by two master locksmiths, Johann Christian Winz and Peter Wisshofer, who were members of the Corporation, and were assigned to serve as patrons for the apprentice. It was their obligation to make certain that he received good care and adequate instruction from his master. While he worked in Butzjäger's shop, Bertolla lived with the master's family in their home.

Bertolla's 3 years at Neulengbach passed quickly as he sought to absorb all that his master could teach him. Butzjäger was considered to be a good craftsman in the region, yet today there is not even a mention of his name in the lists of clockmakers. He specialized in the production and repair of "great clocks" which included tall-case, domestic timepieces, and tower clocks. Butzjäger treated his apprentice well, and in return Bertolla rewarded him by being diligent and honest. His subsequent work is sufficient indication that he developed into an extremely skilled craftsman, and he became the equal of any clockmaker of his time.

The 3 years of apprenticeship were completed and on December 27, 1722, Bertolla received a certificate from the Corporation of Blacksmiths which assured whomever it might concern of Bertolla's skill, diligence and honesty, and permitted him to open his own shop as a clockmaker under the auspices of the Corporation. This document, which has been preserved by Bertolla's descendants, is an interesting record of the organization of the trade guilds in the 18th century, and, for that reason, has been translated from the original German:

We, the Superiors and other masters of the honorable
corporation of municipal blacksmiths, armorers, and of smiths,
in the Imperial City of St. Pölten in Austria by the river
Enns, DECLARE BY THESE PRESENTS put in force by this document
to anyone who waits to hear.... That the honorable and able
BARTOLOMEO ANTONIO BERTOLLA of Rumo in Lentzberg, the Tyrol, on
the 27th day of the month of December of the year 1719 was
consigned as apprentice for three years, in the presence of two
sponsoring masters for the purpose, the honorable Johann
Christian Winz and Peter Wisshofer, both of them master
locksmiths representing the entire honorable Corporation and
others of open shop--to the honorable JOHANN GEORG BUTZJÄGER,
incorporated with us, citizen and master clockmaker for large
clocks in the merchant-village of Neulengbach in Wienerwald, as
his master of the art, would have therefore perfectly and
rightfully worked and learned, and

that afterwards, on the day and year noted at the bottom, he
will be newly declared free and independent before us,
representative of an entire and honorable Corporation and with
open shop, of his above-mentioned master and of the two
sponsoring masters mentioned,

and since he eagerly requested a truthful certificate of
apprenticeship for his honest service as an apprentice and for
his good behavior, and we having great pleasure as well as the
duty of favoring the truth and well knowing that the aforesaid
BARTOLOMEO ANTONIO BERTOLLA has learned honestly the art of
clockmaking for great clocks from his aforesaid master, and
that he has always behaved with honesty, obedience,
faithfulness and diligence both towards his master and towards
us to our complete satisfaction and, therefore, we cannot in
any manner refuse his request, rather we wish to grant it with
a clear conscience.

WE THEREFORE ADDRESS TO EVERYONE and to anyone in whatever
state and rank, but particularly to those interested in our
branch of this art, our respectful and courteous entreaty and
request to consider BARTOLOMEO ANTONIO BERTOLLA well
recommended for his honest apprenticeship and his good
behavior, and to desire to favor him in every way, in such a
manner that will assure our gratitude whenever an occasion
presents itself.

For this purpose, we issue, as we have declared we wish to
issue to you, BARTOLOMEO ANTONIO BERTOLLA, this certificate of
apprenticeship, attaching to it the seal of our Corporation.

Executed in the city of St. Pölten on 27 December 1722.[12]

His apprenticeship over, Bertolla returned to his native region where he soon established a reputation for himself as one of the most skillful clockmakers in the Tridentina and produced timepieces of fine quality in some quantity. No records have survived concerning his personal life, but it is believed that he married probably soon after his return. He had no children of his own. To expand his business, he eventually took into his shop two nephews, the sons of a brother and a sister, as apprentices.

Bertolla's work brought him a sufficient number of clients, and he produced elaborate clocks for his more wealthy patrons.

In 1752, it is recorded that he repaired the great clock in the campanile of the Church of the Assumption of the Virgin Mary in Cles, the regional capital of the valley of the Non. The clock dated probably from the 16th century, and it seems likely that Bertolla replaced the original two-wheel train with a three-wheel movement, and that he added the present anchor escapement.[13]

It is not possible to determine when Father Borghesi first made Bertolla's acquaintance, but it may be assumed that they had become friends in the late 1750's.

After he had come to know Bertolla, Father Borghesi apparently spent many hours in the clockmaker's shop. He was fascinated by mechanics in any form, and the complications of clockwork particularly intrigued him. Bertolla was patient with the young priest, explaining the tools he had and their uses, the clocks he produced or repaired, and the principles which were involved. Father Borghesi listened willingly and as his understanding of timepieces grew, his curiosity increased.

In spite of himself, the priest could not be satisfied with the ordinary aspects of his friend's work and wanted to learn more. From a casual pastime, the study of time became an obsession with him. There was but one recourse: he went back to studying once again. This time it was not theology, however, but the sciences. Every moment he could spare went into the perusal of books on mathematics, astronomy, and associated subjects. He progressed rapidly, driven by his overpowering interest and aided by his quick intellect.

Little by little, Borghesi managed to acquire the basic texts that explained this new world to him, probably borrowing them from old seminary friends. As each new book came into his hands, he devoured it in his desire to master its contents. He discussed each new principle or precept that he learned with Bertolla. Together, they attempted to apply his new learning to the calculations necessary for a timepiece which would demonstrate the astronomical theories in visual form. Borghesi taught himself slowly, step by step, and the result was a profound understanding of astronomical science. He conceived the project of constructing a great astronomical clock which he felt could be accomplished by combining Bertolla's mechanical skills with his own recent mastery of astronomy and mathematics.

First Borghesi Clock

It is not difficult to visualize the two men, the priest and the clockmaker, as they sat together night after night working out their plans. Father Borghesi would painstakingly outline the astronomical principles he wished to have the clock exhibit and the mathematical principles which would be involved to operate them. Bertolla concentrated on them and tried to transcribe the principles into functional mechanical terms, visualizing each operation in terms of wheels and gears. Little by little the two men coordinated the numerous elements and welded them into an operating entity. They adjourned either to the stark simplicity of the rectory or, probably more often, to Bertolla's little home workshop, the priest standing over his friend while the latter worked at his bench in the dark paneled interior illuminated only by the several lamps on the work benches.

This first clock which the two men combined to create is a monument to the great scientific knowledge of the self-taught priest and the technical ability of the clockmaker--a unity combining astronomical science, mechanics, and artistry. The story of the project is told in a little book, _Novissima Ac Perpetua Astronomica..._, which Borghesi later published. Explaining the incentive which inspired him, and the premises from which he began his work, he wrote:

From the foundation of astronomical science long ago,
innumerable [and] repeated observations of both ancient and
modern astronomers, emerged at last from their hiding places.
Made light of by the jests of so many outstanding intellects,
they have so successfully brought to light the paths of the
stars and their motions, which are more complicated to us than
the Gordian knots. Now it is possible for even an amateur in
astronomy, sufficiently instructed, to predict for any given
time not only the mean position of the planets, but also their
true longitude and latitude, and even the true time of their
conjunctions, and their ecliptic oppositions, with all the
attendant circumstances. Yet, until now, no hypothesis has been
devised which would force an automaton to show to us, before
our very eyes, the eclipses of the planets in their true and
certain times.

For though there have been men seeking with all their might to
bind by laws their artificial heavens, by I know not how many
and how great calculations, and to systematize the complexities
of the rotations of celestial bodies; nevertheless, all of
them, as if by common agreement, considered themselves to have
made great contributions to mechanico-theoretical astronomy.
However, they have only attained, even though closely, the mean
locations of the secondary mobiles, and those by a certain
rather crude calculation. Some attained by more, some by less,
but all by some degree of wandering from the truth, either worn
out by the intricacies of the motions, or deceived and
deceiving by the errors of their calculations. This fact those
well know, who, setting about to collect information of this
kind, even those publicized not long ago, with true
astronomical calculation, have been bored to death while
digging out by the most elementary and superficial arithmetical
torture, the worst of fallacies spontaneously erupting from
thence.

It would seem that true calculations alone can be desired in
mechanico-astronomics. Long study had not only convinced me
that an automaton was within the realm of possibility, but that
there were many mechanical systems by which it could be
achieved. I girded myself for a new project and developed it
theoretically from the ground up, but under such unhappy
auspices that not only did all hope fail that anyone would ever
appear who might have seemed willing to set his hand to the
work, but that the new discovery itself was scoffed at by many
as altogether a nightmarish delirium of an unbridled
imagination.

The first months of the project must have seemed like an inspired dream to the two men, and then must have followed a period of hopeless depression. Bertolla undoubtedly felt many times that the clock was an aspiration far beyond their combined abilities and means, but the priest would not be thwarted in his ambition and refused to abandon the project. He felt that it was a work that they were destined to produce. Many times, he wrote, he chided and begged and shamed his erstwhile partner into resuming the project where it had been last abandoned. Little by little, the first clock began to take form. As each new difficulty was encountered, the two men would go back over the notes and sketches to trace the problem to its source. Often a new part of the mechanism would nullify another which had thus far operated successfully, and a complete rearrangement would be required.

the true new full moons and the true quadrature, etc., of the sun and moon appear, but also, all solar and lunar eclipses--both visible and invisible; as in heaven, so on the clock, they are conspicuously celebrated in their true times, and those of the past and those of the future, with their circumstances of time and duration, magnitude, etc., can be quickly determined. All this was devised and brought to light by the author, Francesco Borghesi of Anáuni, a secular priest of Trent, A.A.L.L. & Doctor of Philosophy. (Trent: From the printshop of Giovanni Battista Monauni, With Permission of Superiors.)" (_Title page reproduced by permission of the Biblioteca della Citta di Trento._)]

Again and again, Bertolla threw up his hands in despair and begged Father Borghesi to abandon the enterprise. He protested that he was not capable of producing such a complicated mechanism; he had neither the tools nor the skill. The priest wished to produce a clock such as the world had never seen before, such as the greatest scientists and clockmakers of all time had never been able to make. But Bertolla felt that he was only a provincial craftsman who could not hope to surpass them all with only his simple tools and training.

In his book on the first clock, _Novissima Ac Perpetua Astronomica..._, Father Borghesi wrote that when he had finally come within a few weeks of the embryo stage in the development of his clock, he was faced with the problem of bolstering the sagging enthusiasm of Bertolla. The clockmaker's original enthusiasm had shown promise of great results, but as the days passed and the problems of the multiplex and generally unfamiliar apparatus to be forged for the workings of the automaton became more complex, his ardor decreased. Finally, Bertolla became so discouraged by the scoffers and frustrated by the fact that the work was insufficiently organized that Father Borghesi wrote that "it almost became a harder task for me to bolster up by daily opportunity and importunity the failing patience of the artisan, frightened away from the work already begun, than it was for me to extract from the inner recesses of mathematics and astronomy, without light and without a guide, the whole fabric of the machine itself!"

In spite of Bertolla's protests, Father Borghesi prevailed, reviving his friend's interest once more until the two were deep in the project again. Months passed as they worked together on the mechanism and it seemed as if they lived for no other purpose. Inevitably, Bertolla's health began to suffer, undermined as it was by the constant nervous tension, and he eventually became ill from mental strain. He was forced to spend some time in bed, and for many weeks the subject of the clock was not discussed. Bertolla's other work, by which he made his living, suffered and it was several months before he was able to return to his little shop.

One year passed into another and the work progressed slowly. The first clock, which easily should have been finished in less than a year, was not completed until after three full years had passed. However, when the priest and the clockmaker put the finishing touches to their great clock, the result surpassed the greatest possible expectations, for it was truly a masterpiece. Not only did it illustrate the ecliptic phenomena of the moon, the sun and earth occurring in their proper time, as well as many other things, but it showed these operations as they succeeded in proper order, taking place through the centuries.

With mutual feelings of great pride, the two friends surveyed the result of their three years of endeavor. Bertolla realized that he had reached a point of maximum achievement in his work. He probably felt that now he could relax again, that his sleep would no longer be troubled by confused nightmares of wheels and gears that did not mesh together. Time was to prove otherwise.

PUBLISHED DESCRIPTION OF THE FIRST CLOCK

Father Borghesi soon came to the conclusion that it would be desirable to have a written description to explain the mechanism of the clock and its many indicators. He thereupon wrote out the story of how the clock was made, the reasons for embarking on the enterprise, the difficulties he had encountered, and the success which had crowned his and Bertolla's mutual labors. Finally, he described the operation of the clock's mechanism and the functions of its array of indicators.

The little book was written in Latin and only a few copies were printed, presumably at the priest's own expense, on a handpress by Giovanni Battista Monauni, printer to the Bishop in Trent. The little volume was stated by contemporary writers to have been published in 1763, although no date appears on the title page. The title translated is, in part, _The Most Recent, Perpetual Astronomical Calendar Clock, Theoretical--Practical...._ The work begins with an introduction for the reader in which Father Borghesi stated that:

... the little work, which, as far as I was concerned could
easily have been finished in a year, was only completed after
about three years. Fortunately, however, it was so far beyond
the expectations of most, that not only am I able to foretell
with certainty all the lunar ecliptic phenomena and the solar,
or rather terrestrial, phenomena, carefully worked out in their
true periods, among many other matters exhibited by the
machine; but also, within a few hours, I can exhibit by
altogether tangible evidence to the skeptics and the doubting
those very same phenomena, occurring within the space of many
years, or even centuries, and succeeding one another in proper
order, with their many attendant circumstances. I was not much
concerned about the other eclipses, such as those of Mercury,
Venus, and the other stars wandering through the zodiac, or
about the other solar eclipses from the transit of Mercury or
Venus, since they are altogether undiscernible to the naked
eye, and very few compilers of ephemerides wish them to be
noted, probably for the same reason.

Do not, however, expect, star-loving reader, that here anything
at all that you may wish can be drawn forth as from its source,
for to demand this would be almost the same as to seek to drain
as from a cup all the vast knowledge of the many arithmetical
sciences from the narrow confines of one book. You will
understand how impossible that is when, through prolonged
labor, you have grown somewhat more mature in this kind of
learning.

Wherefore, rather fully, and out of consideration for you, I
have decided, setting aside these prolixities, with completely
synoptic brevity and with all possible clarity to expound for
you simply the proportion of the movements, the description of
the machine, and its usage. As a result, when you have
progressed a little in theoretical mechanics, you will not only
be able to reduce all these things to their astronomical
principles, but you may find the way more smoothly laid out for
you even for perfecting the machine itself. And, thus, you may
be more effectively encouraged to a successful conclusion. Let
it be so now for you through the following 10 chapters!

After these rather hopeful assurances, Father Borghesi proceeded to provide a detailed description of the clock dial and functions in the 10 short chapters which he had promised, under a separate section entitled "Synopsis Totius Operis Mechanici," which is translated in its entirety in the appendix.

As Father Borghesi prepared his little volume about his first clock, and described its unusual features and outlined its functions, which were primarily to place in evidence the celestial constellations, it occurred to him that it would now be easier after the experience he had acquired with his first timepiece, to construct another clock, which would present the motions of the two astronomical systems, the Ptolemaic and the Copernican. In this first book, he promised the reader that he would undertake the second project. It is fortunate that Father Borghesi undertook this project for the second clock is the only example of his work that is known to exist today. Extensive research has not shown what happened to the first clock, although several sources state that both timepieces were presented to Empress Maria Theresa sometime between 1764 and 1780.

Second Borghesi Clock

Father Borghesi lost no time in initiating the project of the second clock. The first and most important step was to inform Bertolla and enlist his assistance. Bertolla was adamant: he had had enough of complicated astronomical movements. He was delighted by the prospect of returning to his former simple life, producing simple, domestic, elementary movements for his country clients. Father Borghesi begged and cajoled. The second clock would be a much simpler one to construct, he persisted. After all, they had gained invaluable experience from the production of the first clock. Furthermore, he had already completed its design.

Bertolla apparently wavered in his resolve and, unwillingly and against his better judgment, he allowed the priest's inducements to prevail. Once again, the two friends yielded their leisure hours to a study of the priest's books and drawings as Father Borghesi enthusiastically elaborated his design for the timepiece, and Bertolla attempted to transcribe astronomical indications into terms of wheel counts. The second clock was, as Borghesi had promised, much easier of execution. Within a year, it was completed and functioned with complete success.

This is the clock now in the Museum of History and Technology. It is housed in a tall case of dark-red mahogany veneered on oak, with restrained carving featuring ribands and foliate motifs. Gilt-brass decorations flank the face of the hood, which is surmounted by three gilt-brass finials in the form of orbs. A wide door in the waist may be opened to attend the weights. The case is 7 feet 8 inches high, 20-1/2 inches wide at the waist, and 14 inches in depth.

The dial is of gilt brass, measuring 21 inches high and 15 inches in width, with a number of supplementary silvered dials visible through its openings. Instead of hands, the dial utilizes three concentric rings moving around a central disc, the indications of which are read at two bisecting gilt lines inscribed in the glass face. Twelve separate functions are performed by the chapter ring assembly alone, and there are 14 openings on the dial. It is estimated that the clock performs 30 separate functions, including striking and chiming. Of the multiple chapter rings, the outermost is 1-1/8 inches wide, the center ring is 3/8 inch wide, and the innermost ring measures 1-1/4 inches in width.

THE DIAL-PLATE ENGRAVINGS

The gilt dial is incised throughout with figures and inscriptions in engraving of the very finest quality, as is evidenced in the illustrations. The frontispiece is surmounted at its center by the crowned double eagle of the House of Hapsburg, indicating the identity of the sovereign in whose reign it was made, Emperor Francis I or the Empress Maria Theresa of Austria. Below the eagle at either side are flying cherubs supporting ribands with inscriptions. Centered at the bottom of the frontispiece immediately above the chapter rings is the moving silvered orb representing the sun. Surrounding it is a tableau of the Holy Trinity, with the Virgin Mary being crowned by Christ holding a cross at the left and God with a sword in hand at the right, and a dove representing the Holy Spirit hovering over the Virgin's head. Father S. X. Winters, S.J., considers it reminiscent of the triptych "The Coronation of the Virgin" by Fra Lippo Lippi.

KEY TO DIAGRAM OF THE DIAL PLATE

A Dominating planet, represented by its symbol and its house;

B Dominical letter (Lit. Dom.);

C Epacts (Cyc. EpEC);

D Roman indiction (Ind. Rom.), part of the reckoning of the Julian period;

E Solar cycle, (Cyc. Sol.), part of the reckoning for the Julian period;

F Golden number (Num. Aur.), part of the reckoning for the Julian period;

G, H, I, J The era, or the current year; part of the six windows of the Iris, or rainbow;

K Shuttered winding hole, for winding up the weights; part of the six windows of the Iris;

L The era, or the month of the current year; part of the Iris, or six windows of the rainbow;

M The sun in its epicycle;

N The 12 signs of the sun's anomaly;

O, P The first chapter ring representing the equatorial globe of the week, revolving from left to right;

Q The coming day indicated through the window;

R The second chapter ring; including the synodic-periodic measure of the tides, the days of the median lunar-synodic age, the signs and degrees of the signs for mean distance of the moon from the sun;

S Epicycle of the moon with signs of its anomaly;

T Head of the dragon (Cap. Draconis);

U Tail of the dragon (Cauda Draconis), for measuring eclipses of the earth and of the moon;

V Third chapter ring, with degrees of lunar latitude and some fixed stars;

W Fourth chapter ring, showing firmament of fixed stars, signs of the zodiac and degrees of the signs, the months of the year, and days of the months, revolving left to right for the course of a mean astronomical year;

X Adjustment marked _Claudit_ (it closes) and _Aperit_ (it opens) for disengaging dial work for the purpose of making astronomical experiments and computations;

Y Adjustment marked _Concitat_ (it accelerates) and _Retardit_ (it retards) for fast and slow adjustments of the movement.

In the upper spandrels of the dial are two more cherubs bearing ribands with inscriptions. In the lower left corner is a magnificent engraving of Atlas upholding the globe of the world, inscribed with the zodiac, over his head. The lower right corner features the figures of two noblemen apparently examining and discussing an orb upon a table, the significance of which is not clear.

THE INSCRIPTIONS

Beginning with the uppermost part of the frontispiece, there are nine inscriptions in Latin on the dial plate. The topmost is _Franciscvs I sit plan. Dominator aeternvs._ The phrase has reference to Francis I, who was Emperor of the Holy Roman Empire, from 1745-1765, and husband of Empress Maria Theresa of Austria. The phrase may be translated as "May Francis I be the eternal ruler by favor of the planets" or more simply "Long Live Francis I, Emperor."[14] Although the dial plate of the Borghesi clock is inscribed with his name, the records indicate that the clock was presented to Maria Theresa. Francis I may have already died before the presentation was made.

From the left to right over the tableau of the Holy Trinity is the phrase "Lavs sacrosanctae Triadi Vni Deo, et Deiparae" (Praise [be] to the most Holy Trinity, to the one God, and to the Mother of God).

Within the upper left and right spandrels is inscribed:

Isthaec, Signum grande apparvit in Coelo * sancta Dei genitrix
amicta sole * Illibato pede Lvnae et serpentis nigra premens
Cornva * bis senis pvlcherrime Coronata syderibvs * Tempe
indesinenter clavsa, scatvrigo signata * Cedrvs in Libano,
Cypresvs in Monte Sion * Mater pvrae Dilectionis sanctaeqve
spei * Chara patris aeterni proles, Verbi Mater, sponsaqve
procedentis *, gratiae et gloriae circvmdata varietate.

This inscription is a eulogy to the Virgin Mary assembled from the texts of Holy Scripture. In addition, each _lemma_, contained within asterisks, carries out the chronogram 1764, the year the clock was completed. Each _lemma_ is translated and identified from the Douay-Rheims version of the Bible:

This woman: a great sign appeared in Heaven (Apocalypse 12:1) *
The Holy Mother of God clothed with the sun (Apocalypse 12:1) *
And with unharmed foot crushing the black horns of the moon
(Apocalypse 12:1) and the serpent (Genesis 3:15) * Most
beautifully crowned with twice-six (Apocalypse 12:1) * A garden
[_Tempe_[15]] enclosed, sealed with a fountain [spring of
water] (Song of Songs 4:12) * Like a cedar in Lebanon, and a
cypress tree on Mount Zion; (Ecclesiasticus 24:17) * Mother of
pure love and of holy hope: Beloved daughter of the Eternal
Father, Mother of the Word, Spouse of the Holy Spirit:
(Ecclesiasticus 24:24) * Surrounded with a diversity of grace
and glory (Psalms 44:10).

At the lower left corner below the figure of Atlas upholding the world is the phrase, _Assidvo proni donant di cvncta labori_. (The favorable gods willingly grant all things to the assiduous laborer.) The same phrase is quoted by Father Borghesi in the text of his second volume. The last inscription appears at the lower right corner under the figures of the two noblemen, _Diligit avdaces trepidos fortvna repellet_. (Fortune favors the daring and rejects the timid.) The last two inscriptions are in dactylic hexameter. They appear to be original compositions inasmuch as no classical prototypes have been identified.

CENTER DIAL INSCRIPTIONS

In addition to the inscriptions previously noted on the outer dial plate, there are three major inscriptions in the central dial. The outermost states _Circulus horarius Soli_, _Lunae_, _Fixis_, _Nodis_, _Aestuique marino communis_ (the hour circle, common to the sun, the moon, the fixed stars, the nodes and to the sea tide). This inscription is divided into four parts by the insertion of four divisions for the day into canonical hours: [_Horae_] _Nocturnae_ (night hours); _Matutinae_ (morning hours); _Diurnae_ (daytime hours) and _Vespertinae_ (evening hours).

The next section of the central dial is inscribed _Intumescite--Detumescite_ (rise and fall of the tides) repeated at intervals of approximately every six hours. Within the next section is the following inscription, inscribed continuously around the ring:

Lege fluunt, refluunt, dormitant hac maris undae: Ad Phoebi et
Phoebes concordia iussa moventur Aequora; discordi iussu
suspensa quiescunt.

Translated, this is:

By this law the sea waves ebb and flow and lie dormant: When
Phoebus and Diana agree in their commands, the waters are
moved; when they disagree, the waters lie silent.[16]

Within the central boss of the dial plate, the name of the maker is inscribed:

Bvrghesio Doctore, et Bertolla Limatore Annaniensibvs*

Translated, this is:

[By] Doctor Borghesi and Bertolla, mechanician citizens of
Anáuni.

INDICATORS IN THE FRONTISPIECE

There are 12 windows in the frontispiece, through each of which appears an indication relating to time. Beginning at the top of the frontispiece of the dial, the first opening occurs on the breast of the imperial eagle. This indicates the dominating planet, represented by its symbol, and its house.

The opening in the eagle's left claw, labeled "Lit. Dom." is the dominical letter. The first seven days in the month of January are each assigned one of the letters _a_ through _g_ in order of appearance. The letter which coincides with the first Sunday within this period is called the dominical letter, and it serves for the following year. In leap year, two letters are required, one to February 29th and the letter next proceeding for the remainder of the year. This letter is used in connection with establishing the date of Easter Sunday. The date of Easter regulates the dates of the other movable feasts.

The eagle's right claw is labeled "Cyc. EpEC" and represents the epact, or the age of the moon on January 1st. It serves to find the moon's age by indicating the number of days to be added to each lunar year in order to complete a solar year. Twelve lunar months are nearly 11 days short of the solar year, so that the new moons in one year fall 11 days earlier than they did the preceding year. However, 30 days are deducted as an intercalary month since the moon has made a revolution in that time, and the remainder, 3, would be the epact.

Below the imperial eagle two winged cherubs support a riband with three indictions of the Julian period. This period of 7980 years is the product derived from multiplying together the sums of 28, which represents the cycle of the sun; 19, representing the cycle of the moon; and 15, which represents the Roman indiction. The Julian period is reckoned to have begun from 4713 B.C. so that the period will be completed in A.D. 3267. The first of the three openings is marked "Ind. Rom." or "Roman indiction," which was an edict by the Emperor Constantine in A.D. 312, providing for the assessment of a property tax at the beginning of each 15-year cycle. It continues to be used in ecclesiastical contracts. The second opening, which occurs immediately below the eagle, is marked "Cyc. Sol." (cycle of the sun). This cycle takes a period of 28 years, after which the days of the week once again fall upon the same days of the month as they did during the first year of the former cycle. There is no relationship with the course of the sun itself, but was invented for the purpose of determining the dominical letter which designates the days of the month on which the Sundays occur during each year of the cycle. Since cycles of the sun date from 9 years before the Christian era, it is necessary to add the digit 9 to the digits of the current year and then divide the result by 28. The quotient is the number of cycles which has passed, and the remainder will be the year of the cycle answering to the current year. The third opening on the riband is labeled "Num. Aur." (golden number). Meton, an astronomer of Athens, discovered in 432 B.C. that after a period of 19 years the new and the full moons returned on the same days of the month as they had before, and this is called the cycle of the moon. The Greeks were so impressed with this calculation that they had it inscribed in letters of gold upon stone, hence the golden number. The First Council of Nicaea in A.D. 325 determined that Meton's cycle was to be used to regulate the movable feasts of the Church.

Immediately above the chapter rings is an opening through which the orb of the sun is visible.

THE CHAPTER-RING ASSEMBLY

In a separate chapter in his second volume, entitled "Descriptio Authomatis Summa totius Operis Mechanici" (Description of the Automaton--Summary of the Complete Mechanism), Father Borghesi provided a description of the functions of the various indicators, prefixing it with the short poem shown in figure 18. He then continues:

In the middle of the frontispiece, as at the center of the
universe, the terraqueous globe of the week revolves, with a
daily motion turning from right to left, bringing with it from
the round window the coming day and at the circumference the
circle of hours common to the sun, to the moon, to the fixed
stars, to the head and tail of the dragon, and to the raging
sea.

The second circle revolves the synodic-periodic measure of the
raging sea, the days of the median lunar-synodic age, the signs
and individual degrees of the signs of the distance of the moon
from the middle of the sun within the time of 29 terrestrial
revolutions, hours 12.44.3.13. This circle revolves likewise
from right to left around the center of the earth. In this
second circle, another little orb revolves, bringing with it
the epicycle of the moon, in which the little circle of the
moon (whose illuminated middle always faces towards the sun),
running from left to right through the signs of the anomaly;
within 13 revolutions of the earth, hours 18.39.16. It descends
from apogee to perigee and in just as many others it returns
from perigee to apogee, to be carried down thus to true, back
and front from the longitude and distance from the sun and from
the middle of the earth.

The third circle (on which I have tried to indicate
astronomically-geometrically in their places, the degrees of
lunar latitude both in the south and in the north, and some
fixed stars, those, namely, which can be separated by us from
the moon which goes between) from left to right turns around
the center of the earth, stretching out the head and tail of
the dragon, on the inside above the second circle for noting
and measuring the sun (but I should rather say the earth), and
the eclipses of the moon, within 346 revolutions of the earth,
hours 14.52.23.

The fourth circle, in which the heaven of the fixed stars,
reduced to the correct ascent of our times, the signs of the
zodiac and the individual degrees of the signs, the months of
the year and the single days of the month can be seen, likewise
makes its journey around the earth from left to right in 365
terrestrial revolutions, hours 5.48.56.; that is, within a
median astronomical year. Above this annual orb, the sun, in
its small epicycle, gliding through the 12 signs of the
anomaly, within the space of 182 terrestrial revolutions, hours
15.6.58., from left to right, falls from apogee to perigee;
and, within the same time, rises from perigee to apogee, and
brings with it, the index, namely its central radius, inhering
to the axis of the equatorial orb and cutting the four greatest
circles from the center.

When the sun has been moved around, Iris shows from six windows
the era, that is, the current year. Two winged youths take
their place next to Iris, carrying the Julian period: namely,
the Roman indiction, the cycle of the sun and the golden
number, on a leaf of paper held between them. The imperial
eagle stands out on top (as if added to the frontispiece)
carrying on its breast the dominating planet and in its talons
the ecclesiastical calends (that is, the dominical letter and
the epact).

ATTACHMENTS FOR ADJUSTMENT

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.

THE CLOCK MOVEMENT

Father Borghesi specified that the entire mechanism was equal in weight to a seventh part of a _Centenarii Germanici_, a Germanic hundredweight. This is probably the Austrian centner which is equivalent to 123.4615 pounds. Therefore, the clock mechanism weighs approximately 17.6 pounds.

The clock operated for a hundred days and more at a single winding, according to Father Borghesi, and by means of a pendulum with a leaden bob weighing 60 Viennese pounds, attached at a height of 5 feet. Father Borghesi stated the weight of the pendulum to be 60 _librarum Viennensium_, but the Viennese libra does not appear among the weights of the Austrian Empire. However, using the average libra, an ancient Roman unit of weight equal to 0.7221 pound, it may be assumed that the driving weight should be approximately 45 pounds.

Father Borghesi, however, does not venture to provide any description whatsoever of the movement of his second clock in his book. He gave the following reasons:

But beyond this, I entirely omit [a description of] the further
apparatus of the very many wheels, etc., inside the clock which
carry on its functions, lest I become too verbose for some
persons. To explain more thoroughly the internal labyrinth of
the entire mechanism, from which the movement of the circles or
heavens, etc., are derived, would seem to entangle in too many
complicated perplexities.... Therefore, that I might not delay
longer, and perhaps to no purpose, I have thought it better to
leave the whole work to the proportionate calculus of the
arithmeticians and the technical skill of mechanics. If they
have any desire to construct a similar mechanism, they will
follow the aforesaid motions of the heavens, etc., not only by
one means alone but by many, more swiftly through thoughtful
study than by any amount of instruction.

For whoever is well versed in the theory of calculus and sets
to work at any given project, will discover any desired motion
by a thousand and more ways, by one or another gearing of
wheels; which an industrious mechanic will carry out in
actuality and without too much difficulty. Nor is there any
reason for anyone to be discouraged, so long as he is not
disgusted by the amount of labor for there is nothing truer
than the old saying "The favorable gods grant everything to the
assiduous laborer."

Nay, further, even this little work itself can be improved on
and surpassed by new inventions. Otherwise that other old
adage, almost as old as the world, would prove false, "What you
have found already done, you can easily repeat, nor is it
difficult to add to what has already been invented." Relying on
this principle, I have already conceived some new things to be
added to the present little work.

THE BELLS

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.

CHRONOGRAMS

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.

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:

FranCIsCVs I sIt pLan. DoMInator aeternVs

The letters which are intended to form the chronogram are: