FOOTNOTES:

Figure 21.—Tall-case clock by Bertolla in the Episcopal Palace in Trent, made for Bishop Cristoforo Sizzo di Noris. A striking and repeating clock with lunar phases. (Courtesy of Museo Nazionale della Scienza e della Tecnica, Milan.)Figure 21.—Tall-case clock by Bertollain the Episcopal Palace in Trent, made for Bishop Cristoforo Sizzo di Noris. A striking and repeating clock with lunar phases.(Courtesy of Museo Nazionale della Scienza e della Tecnica, Milan.)

The ingenuity displayed in the Borghesi clock by its constructor, Bartolomeo Antonio Bertolla, requires a consideration of the other examples of his work that have survived. The most important of his clocks are probably the one in the Episcopal Palace at Trent and another made for the Baron of Cles.

The one which survives in the Episcopal Palace to the present time, is extremely tall and is housed in an elaborately decorated narrow case of black or ebonized wood approximately 9 to 10 feet in height. The upper part of the case is decorated with elaborately carved and gilt rococo motifs. The movement operates for one year at a winding, indicates and strikes the hours, and shows the lunar phases. It has an alarm, and will repeat the strike at will, indicating the number of the past hour and the quarters. The gilt brass dial is decorated with silver-foliated scrollwork in relief at the corners, inside the chapter ring, and within the broken arch. Featured above the chapter ring is the coat of arms, executed in silver, of the patron for whom the clock was made, Cristoforo Sizzo di Noris. Di Noris was Bishop of Trent for 13 years, from 1763 to 1776.

The clock which Bertolla made for the Baron of Cles is a tall, narrow, case clock of ebony or ebonized pearwood which is approximately 9-1/2 feet in height. The decoration of the case is considerably more conservative than the one made for Di Noris, but the black wood is decorated with silver trim and carved designs in the wood itself. The dial is decorated with silver scrollwork and spandrels within and around a raised chapter ring. The clock operates for one month at each winding, has an alarm, indicates and strikes the hours, and will repeat the quarters. This handsome timepiece is still in the possession of the descendants of the Baron of Cles.

According to Pippa,[19]certain characteristics become apparent in a study of the surviving clocks by Bertolla. The tall-case clocks are narrow and range in height from 7-3/4 feet to 10-1/2 feet. The cases had this excessive height in order to obtain the greatest fall for the month and year movements which Bertolla constructed. For the weight assembly, he substituted a drum wound with a key at the point of the driving wheel in place of the customary pulley. The addition of an intermediate wheel augmented the drop of the weight.

Figure 22.—Interior of Bertolla's workshop, showing detail of ceiling. (Courtesy Museo Nazionale della Scienza e della Tecnica, Milan.)Figure 22.—Interior of Bertolla's workshop, showing detail of ceiling.(Courtesy Museo Nazionale della Scienza e della Tecnica, Milan.)

Figure 22.—Interior of Bertolla's workshop, showing detail of ceiling.(Courtesy Museo Nazionale della Scienza e della Tecnica, Milan.)

Figure 23.—Interior of Bertolla's workshop, showing the main workbench and the collection of clockmakers' tools. (Courtesy of Museo Nazionale della Scienza e della Tecnica, Milan.)Figure 23.—Interior of Bertolla's workshop, showing the main workbench and the collection of clockmakers' tools.(Courtesy of Museo Nazionale della Scienza e della Tecnica, Milan.)

Figure 23.—Interior of Bertolla's workshop, showing the main workbench and the collection of clockmakers' tools.(Courtesy of Museo Nazionale della Scienza e della Tecnica, Milan.)

Figure 24.—Fusee cutter used by Bertolla. Now in the collection of the Museo Nazionale della Scienza e della Tecnica, Milan.Figure 24.—Fusee cutterused by Bertolla. Now in the collection of the Museo Nazionale della Scienza e della Tecnica, Milan.

Figure 24.—Fusee cutterused by Bertolla. Now in the collection of the Museo Nazionale della Scienza e della Tecnica, Milan.

Figure 25.—Interior of Bertolla's workshop, showing details of paneling and floor case with Bertolla manuscripts. (Courtesy of Museo Nazionale della Scienza e della Tecnica, Milan.)Figure 25.—Interior of Bertolla's workshop, showing details of paneling and floor case with Bertolla manuscripts.(Courtesy of Museo Nazionale della Scienza e della Tecnica, Milan.)

Figure 25.—Interior of Bertolla's workshop, showing details of paneling and floor case with Bertolla manuscripts.(Courtesy of Museo Nazionale della Scienza e della Tecnica, Milan.)

Bertolla's movements were solidly constructed from well-hammered brass and iron. He favored the recoil anchor escapement in his clocks and the Graham dead-beat anchor escapement with a seconds' pendulum. The escapement was not always placed in the traditional location in the upper center between the plates. Bertolla occasionally displaced the pendulum to one side, to the lower part of the movement or placed it entirely between two other small plates.[20]

He utilized every type of striking work, including the music-box cylinder common in the clocks of the Black Forest and the rack and snail. Bertolla most frequently employed the hour strike andgrand sonnerie. He often used a single hammer on two bells of different sound with the rack and snail. An example of this type is the clock he produced at the age of 80. To achieve the necessary axis of rotation for the hammer, which is perpendicular to the plate when it strikes the hours, it moves to an oblique position and displaces one of the two long pins in an elongated opening.

Bertolla's dial plates were generally well executed,with a raised or separate chapter ring applied to a brass or copper plate, such as a copper-platerepousséand gilt with baroque motifs, or upon a smooth brass plate with spandrels ofrepousséwork usually of silver, in relief and attached. The engraving of the chapter rings was excellent. The hands were well executed in steel or perforated bronze, and occasionally ofrepoussécopper; gilt was applied to the hands made of forged steel.

Figure 26.—Dial plate of a brass lantern clock made by Bertolla, found in his workshop after his death. (Courtesy of Museo Nazionale della Scienza e della Tecnica, Milan.)Figure 26.—Dial plateof a brass lantern clock made by Bertolla, found in his workshop after his death.(Courtesy of Museo Nazionale della Scienza e della Tecnica, Milan.)Figure 27.—Movement of a brass lantern clock made by Bertolla. (Courtesy of Museo Nazionale della Scienza e della Tecnica, Milan.)Figure 27.—Movementof a brass lantern clock made by Bertolla.(Courtesy of Museo Nazionale della Scienza e della Tecnica, Milan.)

Figure 26.—Dial plateof a brass lantern clock made by Bertolla, found in his workshop after his death.(Courtesy of Museo Nazionale della Scienza e della Tecnica, Milan.)

Figure 27.—Movement of a brass lantern clock made by Bertolla. (Courtesy of Museo Nazionale della Scienza e della Tecnica, Milan.)Figure 27.—Movementof a brass lantern clock made by Bertolla.(Courtesy of Museo Nazionale della Scienza e della Tecnica, Milan.)

Figure 27.—Movementof a brass lantern clock made by Bertolla.(Courtesy of Museo Nazionale della Scienza e della Tecnica, Milan.)

In the course of time, Bertolla's home workshop passed from one generation to another within the family. Inevitably, it underwent many modifications until the only original part of the building that remained intact from Bertolla's time was his clockshop.

Within the last few years, the workshop room was acquired complete with contents from Bertolla's descendants, and installed in the Museo Nazionale della Scienza e della Tecnica in Milan as an exhibit of a typical 18th-century clockmaker's shop. The original workshop was dismantled in Mocenigo di Rumo and completely rebuilt in the museum, including the walls, ceiling and floor. The paneling and woodwork of the walls and ceiling, which have been preserved intact, are hand-cut fir, with columns, trim and moldings carved by hand. A small painting is featured in the center of the coffered ceiling. The original shop benches and chests of drawers are set around the reconstructed shop and Bertolla's tools and equipment laid out as they had been originally. Other clockmaker's tools and equipment in the museum's collection are also displayed. Approximately 40 percent of the tools are the original itemsfrom Bertolla's shop. Parts of clocks and works in progress are on view on the benches as they were in Bertolla's time.[21]Also preserved in the museum are sketches found in Bertolla's manuscripts, some of which are reproduced on the following pages.

Figure 28.—Detail of wall of Bertolla's workshop, with regulatory clock made by his nephew, Alessandro Bertolla of Venice. Note wheel layouts, etc., scribed in the paneling. (Courtesy of Museo Nazionale della Scienza e della Tecnica, Milan.)Figure 28.—Detail of wallof Bertolla's workshop, with regulatory clock made by his nephew, Alessandro Bertolla of Venice. Note wheel layouts, etc., scribed in the paneling.(Courtesy of Museo Nazionale della Scienza e della Tecnica, Milan.)

Figure 29.—Table clock by Bertolla in the collection of Doctor Vittorio dal Lago of Bergamo. The dial indicates the days of the week and of the month, the names of the months and lunar phases. The clock strikes the hours and quarters and repeats. (Courtesy of Sig. Luigi Pippa of Milan.)Figure 29.—Table clock by Bertollain the collection of Doctor Vittorio dal Lago of Bergamo. The dial indicates the days of the week and of the month, the names of the months and lunar phases. The clock strikes the hours and quarters and repeats.(Courtesy of Sig. Luigi Pippa of Milan.)

The shop contains two completed clocks made by Bertolla. One is a weight-driven lantern clock typical of the 18th century, Italian style with brass dial, plates and posts, anchor escapement, and striking work. The dial is engraved in the usual style of Bertolla's baroque design, and the hands are of pierced bronze. Another clock associated with Bertolla and found in the shop, was made by his nephew, Alessandro Bertolla, who worked in Venice after his apprenticeship with his uncle had been completed. This clock is a regulator with a seconds' pendulum and sweep hand on an enameled dial. The original case has not survived.

Figure 30.—Layout of the wheelwork of a clock made by Bertolla for His Excellency Paulo Dona, inscribed "Design No. 1." (Courtesy of Museo Nazionale della Scienza e della Tecnica, Milan.)Figure 30.—Layout of the wheelworkof a clock made by Bertolla for His Excellency Paulo Dona, inscribed "Design No. 1."(Courtesy of Museo Nazionale della Scienza e della Tecnica, Milan.)

Figure 30.—Layout of the wheelworkof a clock made by Bertolla for His Excellency Paulo Dona, inscribed "Design No. 1."(Courtesy of Museo Nazionale della Scienza e della Tecnica, Milan.)

Figure 31.—Pendulum arrangement sketch for an unidentified clock found in Bertolla's workshop. (Courtesy of Museo Nazionale della Scienza e della Tecnica, Milan.)Figure 31.—Pendulum arrangement sketchfor an unidentified clock found in Bertolla's workshop.(Courtesy of Museo Nazionale della Scienza e della Tecnica, Milan.)

Figure 31.—Pendulum arrangement sketchfor an unidentified clock found in Bertolla's workshop.(Courtesy of Museo Nazionale della Scienza e della Tecnica, Milan.)

Figure 32.—Striking clock sketch found in Bertolla's manuscripts. (Courtesy of Museo Nazionale della Scienza e della Tecnica, Milan.)Figure 32.—Striking clock sketchfound in Bertolla's manuscripts.(Courtesy of Museo Nazionale della Scienza e della Tecnica, Milan.)

Figure 32.—Striking clock sketchfound in Bertolla's manuscripts.(Courtesy of Museo Nazionale della Scienza e della Tecnica, Milan.)

Figure 33.—Fifteen-day striking clock sketch, inscribed "Design No. 3," found in Bertolla's workshop. (Courtesy of Museo Nazionale della Scienza e della Tecnica, Milan.)Figure 33.—Fifteen-day striking clock sketch, inscribed "Design No. 3," found in Bertolla's workshop.(Courtesy of Museo Nazionale della Scienza e della Tecnica, Milan.)

Figure 33.—Fifteen-day striking clock sketch, inscribed "Design No. 3," found in Bertolla's workshop.(Courtesy of Museo Nazionale della Scienza e della Tecnica, Milan.)

Figure 34.—Dial plate of a brass lantern clock made by Bertolla at the age of 80. (Courtesy of Museo Nazionale della Scienza e della Tecnica, Milan.)Figure 34.—Dial plateof a brass lantern clock made by Bertolla at the age of 80.(Courtesy of Museo Nazionale della Scienza e della Tecnica, Milan.)Figure 35.—Movement of brass lantern clock produced by Bertolla at the age of 80, showing details of movement and double bell. (Courtesy of Museo Nazionale della Scienza e della Tecnica, Milan.)Figure 35.—Movementof brass lantern clock produced by Bertolla at the age of 80, showing details of movement and double bell.(Courtesy of Museo Nazionale della Scienza e della Tecnica, Milan.)

Figure 34.—Dial plateof a brass lantern clock made by Bertolla at the age of 80.(Courtesy of Museo Nazionale della Scienza e della Tecnica, Milan.)

Figure 35.—Movement of brass lantern clock produced by Bertolla at the age of 80, showing details of movement and double bell. (Courtesy of Museo Nazionale della Scienza e della Tecnica, Milan.)Figure 35.—Movementof brass lantern clock produced by Bertolla at the age of 80, showing details of movement and double bell.(Courtesy of Museo Nazionale della Scienza e della Tecnica, Milan.)

Figure 35.—Movementof brass lantern clock produced by Bertolla at the age of 80, showing details of movement and double bell.(Courtesy of Museo Nazionale della Scienza e della Tecnica, Milan.)

One of the most interesting of Bertolla's clocks, and probably the last one which he produced, was found in his workshop. This timepiece indicates the hours, minutes and quarters by means of a single hand or index. The weight-driven clock strikes the hours and quarters on two bells with a single hammer. The chapter ring, which is soldered to the dial plate, is marked for the minutes on the outer rim and for the four quarters inside it. Over the center of it, is a semicircular opening in the dial plate through which is visible a revolving disk attached behind the dial plate. This disk is marked with the hours and revolves from right to left, the current hour being indicated by a projection from the minute ring. The brass dial plate is engraved with simple floral designs in the corners and around the broken arch. There is no comparison between this crude and simple decoration and the extremely fine quality of the engraving on the dial plate of the Borghesi clock, for instance. In the center of the dial plate is engraved the following:

"Questo orologio l'ideai e lo feci nella mia avanzata età d'anni 80. BartoAntoBertolla"(I designed and made this clock at my advanced age of 80 years. Bartolomeo Antonio Bertolla.)

"Questo orologio l'ideai e lo feci nella mia avanzata età d'anni 80. BartoAntoBertolla"

(I designed and made this clock at my advanced age of 80 years. Bartolomeo Antonio Bertolla.)

FOOTNOTES:[1]Borghesi,Novissimum Theorico-Practicum Astronomicum Authoma Juxta Pariter Novissimum Mundi Systema..., pp. 8-9.[2]Wenham, "Tall Case Clocks," p. 33.[3]Von Bertele, "The Development of Equation Clocks," parts 1 through 5.[4]Engelmann,PhilippMatthäusHahn;Vischer,Beschreibung mechanischer Kunstwerke....[5]Lloyd,Some Outstanding Clocks Over Seven Hundred Years, 1250-1950, pp. 116, 118, 120.[6]San Cajetano,Praktische Anleitung für Künstler....[7]Franch,La Valle di Non.[8]Bonomi,Naturalisti, Medici e Tecnici Trentini, p. 16[9]Ambrosi,Scrittori ed Artisti Trentini, pp. 132, 525.[10]Ibid.[11]Pippa, "Antonio Bartolomeo Bertolla," pp. 22-23.[12]Ibid., p. 22.[13]Ibid., p. 23.[14]The abbreviation in the inscription "pLan" is difficult to interpret. According to Father F. X. Winters, S.J., it may represent "sit planetis" or "sit planetarum." The use of an abbreviation was necessary to prevent the addition of another letter I or M, which would have disturbed the formation of the chronogram desired. Literally, "sit planetis" means "May he be eternal rulerby[orthrough] favor of the planets," while "sit planetarum" is to be translated "May he be eternal rulerofthe planets." Father Winters considered both versions somewhat overexaggerated and proposed that the best translation might be "Long Live Francis I, Emperor."[15]The word "Tempe" refers to the Vale of Tempe, in Thessaly, through which the Peneus River flows. It is between Mounts Olympus and Ossa, and is situated between the town of Larissa and the sea. In mythology, it is told that these mounts were originally joined and Hercules separated them to allow the river to pass between them. The word "Tempe" is also used to mean any pleasant place. Thus, the inscription "Tempe indesinenter clausa, Scaturigo signata" is literally translated "Tempe always closed, A fount of water sealed up" or, freely translated, as "A garden enclosed, a fountain sealed up."[16]"Phoebi" or Phoebus, called Apollo, the sun god; Phoebes or Diana, the moon goddess, sister of Apollo.[17]Pippa, op. cit. (footnote 11), pp. 23-25.[18]Perini,Statistica del Trentino, Biblioteca Communale del Trentino, vol. 2, p. 57 (cons. 6, carta 9);Tovazzi,Biblioteca Tirolese, pp. 406-407.[19]Pippa, op. cit. (footnote 11), pp. 24-25.[20]Piamonte,La Nauna Descritta al Viaggiattore.[21]Esposti, "La Sala 'Innocente Binda' al Museo della Scienza e della Tecnica di Milano," pp. 18-21.

[1]Borghesi,Novissimum Theorico-Practicum Astronomicum Authoma Juxta Pariter Novissimum Mundi Systema..., pp. 8-9.

[2]Wenham, "Tall Case Clocks," p. 33.

[3]Von Bertele, "The Development of Equation Clocks," parts 1 through 5.

[4]Engelmann,PhilippMatthäusHahn;Vischer,Beschreibung mechanischer Kunstwerke....

[5]Lloyd,Some Outstanding Clocks Over Seven Hundred Years, 1250-1950, pp. 116, 118, 120.

[6]San Cajetano,Praktische Anleitung für Künstler....

[7]Franch,La Valle di Non.

[8]Bonomi,Naturalisti, Medici e Tecnici Trentini, p. 16

[9]Ambrosi,Scrittori ed Artisti Trentini, pp. 132, 525.

[10]Ibid.

[11]Pippa, "Antonio Bartolomeo Bertolla," pp. 22-23.

[12]Ibid., p. 22.

[13]Ibid., p. 23.

[14]The abbreviation in the inscription "pLan" is difficult to interpret. According to Father F. X. Winters, S.J., it may represent "sit planetis" or "sit planetarum." The use of an abbreviation was necessary to prevent the addition of another letter I or M, which would have disturbed the formation of the chronogram desired. Literally, "sit planetis" means "May he be eternal rulerby[orthrough] favor of the planets," while "sit planetarum" is to be translated "May he be eternal rulerofthe planets." Father Winters considered both versions somewhat overexaggerated and proposed that the best translation might be "Long Live Francis I, Emperor."

[15]The word "Tempe" refers to the Vale of Tempe, in Thessaly, through which the Peneus River flows. It is between Mounts Olympus and Ossa, and is situated between the town of Larissa and the sea. In mythology, it is told that these mounts were originally joined and Hercules separated them to allow the river to pass between them. The word "Tempe" is also used to mean any pleasant place. Thus, the inscription "Tempe indesinenter clausa, Scaturigo signata" is literally translated "Tempe always closed, A fount of water sealed up" or, freely translated, as "A garden enclosed, a fountain sealed up."

[16]"Phoebi" or Phoebus, called Apollo, the sun god; Phoebes or Diana, the moon goddess, sister of Apollo.

[17]Pippa, op. cit. (footnote 11), pp. 23-25.

[18]Perini,Statistica del Trentino, Biblioteca Communale del Trentino, vol. 2, p. 57 (cons. 6, carta 9);Tovazzi,Biblioteca Tirolese, pp. 406-407.

[19]Pippa, op. cit. (footnote 11), pp. 24-25.

[20]Piamonte,La Nauna Descritta al Viaggiattore.

[21]Esposti, "La Sala 'Innocente Binda' al Museo della Scienza e della Tecnica di Milano," pp. 18-21.

[Translated from the section entitled "Synopsis Totius Operis Mechanici" in Francesco Borghesi's first bookNovissima Ac Perpetua Astronomica Ephemeris Authomatica Theorico-Practica....]

Of three movable indices, the farthest from the center of the dial is fitted with an index on either side and marked with four segments of a circle. Immediately below are five numbers, divided into the days of setting the measure of the mean-synodic age of the moon, and into signs, degrees of the signs, and of the distance of the moon from the sun. These, in each revolution, revolve once around the solar disk superimposed on the mean synodic-lunar disk, and also around the lunar disk. The upper indices, meanwhile, in the two external greatest orbits, measure the time continuously, in the accustomed manner of the Germans—the middle index measuring by hours and the uppermost by the first minutes [of hours].

Inside these three circles, perpendicular above their center, is a small index of the seconds of minutes. At each first minute of time, being the fastest of all, it describes the smallest orbit. Next to this are two other slightly larger circles divided into 30 degrees, one [rotating?] from the right, the other from the left. These two indices are arranged in such a fashion that the one rotating from the observer's left completes its period 12 times during one, mean, solar-astronomical year. The one [rotating] from the right likewise completes its cycle 12 times during the period of one mean-synodic moon. In between these, there is placed another small sphere, divided into 40 arbitrary parts, whose dial does not move automatically, but is moved by hand for speeding up or slowing down the course of the time, or of the perpendicular.

Diagonally from the sides of the center of the three larger indices, six other indices revolve: three on the left from one center, and three on the right from another. The uppermost of the three which are on the right of the observer [and which are] decorated with a small disk of the sun, runs its cycle once during a mean solar-astronomical year. The second measures the distance of the sun from its apogee. The third revolves 12 times, with each lunar revolution from one node to the same [repeated] node. Under the point of the uppermost index, first lie the months of the year which are inscribed, and the days of each month, but having only 28 days assigned to February; then the signs of the zodiac, and their several degrees. The circle corresponding to the middle index, extending through the first semicircle from apogee to the lower perigee and returning through the second semicircle to the upper locations of apogee, shows the true equation or eccentricity of the sun, joined with the little equation of the moon in syzygy. [These equations are] measured by geometric-astronomic proportion for each distance of the sun from its apogee or perigee in degrees, and in sufficiently small parts of degrees, with the title added above in their proper places, whether an addition is to be made to the mean location of the sun or a subtraction from the same, so that the true longitude of the sun may be calculated. Three circles are assigned to the lowest index, of which 30 degrees of distance of the moon from its nodes comprise the larger. The middle circle is based on the hypothesis of the mean invariable diameters (that is, of the sun, the moon, and the terrestrial shadow), and is divided into hours and quarters of duration. The last circle is divided by the trigonometric laws into the inches of magnitude of lunar eclipses. Lying between these circles, there is another eccentric circle (black with a spot) exhibiting the shadow of the earth, in which the little moon sinks itself, carried by the lowest index. In any ecliptic full moons, the patent number of inches of immersion somehow affects the minds of the cultured, but also the scheme of maximum obscuration affects the eyes of the illiterate themselves.

Of the three indices which revolve from the left, the uppermost completes its cycle within 12 hours, just as the hour index. The middle one with two pointers on diametrically opposite sides, carries the marks of conjunction and opposition of the luminous bodies, with a movement equal to the course of the sun from lunar apogee or perigee. The lowest index, fitted with a single pointer, indicates the motion of the moon from its apogee or perigee. Under these three indices, there is situated a common circle, divided into 12 parts, each of which are further divided into 30 parts through its outer circumference. I have said a common circle, for, with respect to the first index, the division represents 12 hours, and the double subdivision representing the double set of minutes of the hours serves for an excitator for anytime at all, at will. For as often as the little index reaches the twelfth hour, first being moved by hand wherever you prefer, a little hammer strikes the little bell many times. But if you observe the second or the third index, the first division provides the signs, and the subdivision of the signs gives the individual degrees of the distance of the sun from the lunar apogee, or of the moon from its apogee, respectively. To this is added two other interior circles from the same center: to the larger is inserted the equation of the center of the moon in its conjunctions and oppositions; and on the smaller the equation of the same moon in its quarters, astronomically-geometrically proportioned to the distance of the moon from its apogee or perigee. In the first case, the equation is to be subtracted from the mean longitude of the moon, descending from apogee to perigee; in the second case, to be added to the mean longitude of the moon ascending from perigee to apogee; and, in the third semicircle of the index, as the rubric directs, common to both equations, added around the center.

Perpendicularly under the center of the machine, two other indices are carried about one and the same center. The one nearer to the observer—bearing in one of two points diametrically opposite the small disk of the sun, in the other the disk of the moon—runs a course equal to the motion of the sun from the head or the tail of the dragon (Draco). The other, of simple construction, marked with a small moon, signifies in like manner the motion of the moon from the head or the tail of the dragon.

Immediately below, there is a larger circle, common [referring] to both these indices, which is divided into 12 parts. Each of these parts in turn, in the outer periphery, is subdivided further into 30 parts, which are the 12 signs of the zodiac and the individual degrees of the signs of distance of the sun and the moon from the head of the dragon.

In the second circle is read the latitude of the moon, measured by degrees, etc., on a trigonometric scale, by signs and degrees of distance of the moon from its nodes, that is, from the head or tail of the dragon. When the second index is descending from the head of the dragon to the tail, the latitude will be to the north of the solar path; that is, the ecliptic. On the other hand, it will be south of the ecliptic when the same index is returning upward from the tail to the head of the dragon as advised by the title inscribed on the third circle.

Finally, on the fourth and last circle are seen more prime minutes of the circle for reducing the orbit of the moon to the ecliptic. That the true longitude of the moon may be obtained more accurately, these must be subtracted from the longitude of the moonalready calculated in the first and third quadrant of the circle of the second index. On the other hand, they are to be added to the same in the second and fourth quadrant, as is noted in their respective places, according to the theory of right ascensions.

Here, then, [you have] as finally completed, delineation of the great index which was partially described before in this book.

From two points of that index which perpendicularly correspond to the center of these circles, a pair of compasses, by an unvaried aperture up to the circumference of the first larger circle, has marked off four segments of a circle. The two larger segments, equal among themselves, in one aperture refer to the sun, and the two smaller in the other, likewise equal, refer to the moon. The one pointer is for determining the solar eclipses; the other, for lunar. Both segments of each division, like little wings of the index, stretch to the extent of the degree of distance of the moon from its nodes, and to which that determined latitude corresponds. On one side, that latitude precisely equals the radii of the earth, the sun, and the moon, as the termini of solar eclipses; and, on the other side, precisely equals the radii of the earth's shadow and of the moon, as the confines of lunar eclipses. The apexes of the last index, diametrically limited [opposite], indicate the age of the moon, and its mean distance from the sun; one pointer, upon which the sun sits, measuring the mean days and degrees from the full moon; the other, on which the moon sits, measuring the mean days and degrees from the new moon.

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.

But lest the various movements of the indices and the various beginnings of the divisions tend to cause some fatigue, the precaution has been taken, that all the indices by common law are moved from the top towards the right of the observer, and from thence all the arithmetic divisions of the circles take their beginning. And lest the multitude of different figures should deceive the eye, the larger divisions of the circles have been marked by Roman numbers, that is, by capital letters of the alphabet; others, in other places, by differently colored numbers. Thus, the movements of the indices, the distribution of the circles and the multitude of numbers not only do not disturb the eyes and the mind, but rather marvelously delight them.

After having completed briefly the description of the dial and the indices and their motions, I have not without reason delayed in satisfying the desires of many who wish to learn at least the method by which, from this mechanism, may be calculated the true times of new and full moons, and their ecliptics. In order to make these matters clearer, it is necessary that they be explained here at greater length.

With the indices, then, adjusted astronomically-geographically to the longitude of any given region, and to the mean time whether past, present or future, and assuming the clock to be in normal operation (as at present it has been for a whole year and more), then the moon will be in conjunction with the sun in the heavens. When the equations on the mechanism are examined, the sun and moon shall be found to be in the same degree of longitude, and in the same part of a degree. There will also be an ecliptic new moon that is in conjunction with a solar eclipse, or rather with a terrestrial eclipse. This will occur if, at that time, both apexes of the first index, located below the center of the clock, are hidden by the two segments of the circle extending from the center of the mechanism through the lowest index.

And the eclipse will be greater and greater and, consequently, visible in more regions of the earth, the more deeply the two pointers, indicating the distance of the sun from its apogee, are hidden in the center of the segments.

But whether the eclipse takes place in the head or in the tail of the dragon, or whether it is north or south, is indicated by the small disk of the sun attached to one of the two pointers hidden by the segments of the circle. If, at that time, the little disk shall be found in the head of the dragon inscribed on the plane of the dial, then the sun has been snatched from the earth and ingloriously entombed, as it were, in the huge jaw of the dragon. Then, ... the heavens themselves will lend aid to the woeful pomp of the senseless funeral in full darkness by suddenly lighting the unhappy lamps of the fixed stars. However, if the little disk occupies the tail of the dragon on the mechanism, then the sun in the heavens also, as if freed from the toils of the immense dragon's tail, will emerge without difficulty.

The center of the eclipse will traverse the hemisphere of the earth north of the solar path, always nearer to the pole of the ecliptic, in proportion to the inclination of the disk to the north. On the other hand, if the little disk inclines to the left semicircle, then the people south of the solar path will enjoy the spectacle of the total central eclipse.

But if the little disk remains neutral (inclining neither way) and remains halfway between the two sections of the circle, then the greatest solar eclipse will take place at the equator and those who live near the poles of the ecliptic will not enjoy a trace of that eclipse. This is because the half of the equatorial diameter enormously outmeasures even the greatest apparent semidiameters of the sun and of the moon, even taking as a norm the smallest horizontal parallax of the moon.

What has been said about the true new moon is to be understood also, proportionately, about the true full moon. For when, with respect to the equations of the centers, the moon shall be distant on the mechanism by a full semicircle from the sun (also in the heavens it will be truly in opposition to the sun) there will be a true full moon. Likewise, the moon in the heavens will be in eclipse if, at the time of opposition, the pointers of the little index (which we mentioned before) situated below the center of the clock are so far away from the belly of the dragon that they are forced to lie under the two smaller segments of the circle which, in all full moons, are always to be moved from the index of the synodic moon to the region of that little index. As a matter of fact, the closer the little pointers approach to the middle of the segments, the more obscured it will be.

You will know, furthermore, that the eclipse of the moon occurs in the head of the dragon if the disk of the little moon, attached to the other point of the little index, is raised to the head of the dragon; conversely, when the little disk of the moon inclines to the tail, the eclipse is taking place in the tail of the dragon.

And, accordingly, when you observe the little moon of the index inclined to one or other section of the circle, so also in the heavens, the eclipse of the moon is only partial and the northern or the southern part of the moon is illuminated.

The current time will indicate whether the lunar eclipse is visible or not. As the new moon ecliptic falls during the day, the eclipse will not be visible, since the earth denies a sight of the moon which is below the horizon. But, conversely, if there are no clouds, the eclipse will be visible anywhere, if theluminous bodies are ecliptically in opposition at night.

Since lunar eclipses appear to all people as being of the same magnitude and duration, and begin and dissipate at the same absolute moment of time, I decided to reveal another facet of this spectacle on the right side of the center of the clock (see chapter III above). There, at the time of the true ecliptic full moon, as the pointer of the third little index shows, you can ascertain the hours, etc., of duration, and the inches of greatest obscuration. The little moon attached to the index is a model of the actual eclipsed moon.

Thus, with the aid of this machine, solar and lunar eclipses of the past can be recalled and future ones can be foreseen. Indeed, if the index of prime minutes is speeded up by hand, whose wheel imparts motion to the other indices and shields, then, the dials and openings will foretell the year, month, day, hour, etc., of any future eclipse. I foresaw that the times would thus be evolved too slowly, and that the clock wheels would be considerably worn by repeated experiments (if, for instance, by the rotation of the index of prime minutes, to whose period only a single hour corresponds, the future new and full moon ecliptics were being investigated). Therefore, I took care that the wheel which immediately communicates motion to the index of the synodic moon should be so fitted internally to the mechanism that by the reversal of any external index, the wheel would be removed from its proper position; whenever desired, it could be quickly and most accurately restored to its proper place.

In this way, since the close meshing of the wheels is released, you can extend the experiment for many years, even for many centuries. You have only to guide with your hand the index of the synodic moon on the circles, always intently observing whether, in the passage which this index makes over the little index, both pointers of the little index are hidden by the segments of the circle. Having observed this, look at the index moved by hand, for if this has carried the solar disk halfway between the two larger segments of the circle to the region of the hidden little index, then you will know that eclipse will be a solar eclipse. On the other hand, you will know that it will be a lunar eclipse, if the index (moved by hand) has carried the moon, situated between the two smaller segments of the circle, to the same region (i.e., the hidden part of the circle). The solar disk and the lunar disk alternately will reveal to you the circumstances of both eclipses. The current year will be given by the Julian period, reducible to any desired epoch, and, contained in the solar cycle, the golden number and the Roman cycle. The month of the year and also the day of the month will be indicated by the pointer of the little index, first on the right side of the clock. And what I have said of future eclipses should be equally understood of past eclipses, so long as the index, which can be moved either way at will, is moved in reverse.

Finally, though 55 wheels were employed to carry so many dials, all are driven by one source of power not exceeding the third part of a Germanic hundred-weight which, suspended at the geometric height of five feet (about the ordinary stature of a man), keeps the whole machine in operation for a hundred days and more.

Although the machine repeats hours and quarter hours at will and, consequently, the number of wheels and the rest of the apparatus necessary for these functions is thereby increased, it has not grown to an unwieldy size, however much one might erroneously imagine it to be. It does not exceed the bulk of ordinary clocks hanging from a wall; indeed, it scarcely equals these.

The entire machine, ready for operation, does not weigh more than 156 ounces, although it is made of steel or brass throughout and further weighted with two bells and a rather large brass dial-plate.

Of course, there are many more things to be said, especially about the mechanical structure of the wheels, but fearing to tire my kind reader unduly by exceeding the bounds of a summary, I am forced to put an end, though unwillingly, to this sufficiently shortened explanation of the work. I have hope of giving satisfaction to many more when I shall have communicated to the learned world another and completely new automatic work, grander than this present one. It is already theoretically completed in all its calculations, but still to be worked out mechanically from the very beginning, if but God, thrice Best and Greatest, bless the undertaking and mercifully grant life and health—to whom be in, and from, and through all things, all honor and glory in eternity and beyond.

The following works have been used in compiling the material for this paper. They are frequently referred to in the text in shortened form.

Ambrosi, Francesco.Scrittori ed artisti Trentini.Trent: Giovanni Zippel, 1883.Bonomi, L.Naturalisti, medici e tecnici Trentini.Trent: privately printed, 1930.Borghesi, Francesco.Novissima ac Perpetua Astronomica Ephemeris Authomatica Theorico-Practica.Trent: Giovanni Battista Monauni, 1763(?).——Novissimum Theorico-Practicum Astronomicum Authoma Juxta Pariter Novissimum Mundi Systema.Trent: Giovanni Battista Monauni, 1764.Engelmann, Max.Philipp Matthäus Hahn. Berlin: Verlag Fischer, 1923.Esposti, Alfredo degli.La sala 'Innocente Binda' al Museo della Scienza e della Tecnica di Milano.La Clessidra(July 1960), anno 16, no. 7, pp. 18-21.Franch, Leone.La Valle di Non.Trent, 1953.Lloyd, H. Alan.Some outstanding clocks over seven hundred years, 1250-1950.London: Leonard Hill, 1958.Mosna, Ezio.Trento.Trent, 1914.Perini, Agostino(compilatore).Statistica del Trentino, Biblioteca Communale del Trentino.Vol. 2, p. 57 (cons. 6, carta 9).Piamonte, Guiseppe.La nauna descritta al viaggiattore.Milan, 1829.Pippa, Luigi.Antonio Bartolomeo Bertolla.La Clessidra(January 1961), anno 17, no. 1, pp. 22-25.San Cajetano, David à.Praktische Anleitung für Künstler, alle astronomische Perioden durch brauchbare bisher noch nie gesehene ganz neue Räderwerke mit Leichtigkeit vom Himmel unabweichlich genau auszuführen, sammt Erweiterung der Theorie des neuen Rädergebäudes.Vienna: privately printed, 1793.Tovazzi, Giangrisostomo.Biblioteca Tirolese.Vol. 2, art. 329, MS. 168, pp. 406-407. Trent, 1780.Vischer, George F.Beschreibung mechanischer Kunstwerke, welche unter der Direktion und Anweisung M. Philipp Matth. Hahn, Pfarrers in Kornwestheim.... Stuttgart: Mezler, 1774.Von Bertele, Hans.The development of equation clocks.La Suisse Horologere(1959-1961), parts 1 through 5.Wenham, Edward.Tall case clocks.The Antiquarian Magazine(May 1927), vol. 8, no. 4, p. 33. [The Borghesi clock is illustrated only from a photograph of the Anderson Art Galleries in New York, and mislabeled "Astronomical Clock made in Jena, 1656, in elaborate mahogany case."]

Ambrosi, Francesco.Scrittori ed artisti Trentini.Trent: Giovanni Zippel, 1883.

Bonomi, L.Naturalisti, medici e tecnici Trentini.Trent: privately printed, 1930.

Borghesi, Francesco.Novissima ac Perpetua Astronomica Ephemeris Authomatica Theorico-Practica.Trent: Giovanni Battista Monauni, 1763(?).

——Novissimum Theorico-Practicum Astronomicum Authoma Juxta Pariter Novissimum Mundi Systema.Trent: Giovanni Battista Monauni, 1764.

Engelmann, Max.Philipp Matthäus Hahn. Berlin: Verlag Fischer, 1923.

Esposti, Alfredo degli.La sala 'Innocente Binda' al Museo della Scienza e della Tecnica di Milano.La Clessidra(July 1960), anno 16, no. 7, pp. 18-21.

Franch, Leone.La Valle di Non.Trent, 1953.

Lloyd, H. Alan.Some outstanding clocks over seven hundred years, 1250-1950.London: Leonard Hill, 1958.

Mosna, Ezio.Trento.Trent, 1914.

Perini, Agostino(compilatore).Statistica del Trentino, Biblioteca Communale del Trentino.Vol. 2, p. 57 (cons. 6, carta 9).

Piamonte, Guiseppe.La nauna descritta al viaggiattore.Milan, 1829.

Pippa, Luigi.Antonio Bartolomeo Bertolla.La Clessidra(January 1961), anno 17, no. 1, pp. 22-25.

San Cajetano, David à.Praktische Anleitung für Künstler, alle astronomische Perioden durch brauchbare bisher noch nie gesehene ganz neue Räderwerke mit Leichtigkeit vom Himmel unabweichlich genau auszuführen, sammt Erweiterung der Theorie des neuen Rädergebäudes.Vienna: privately printed, 1793.

Tovazzi, Giangrisostomo.Biblioteca Tirolese.Vol. 2, art. 329, MS. 168, pp. 406-407. Trent, 1780.

Vischer, George F.Beschreibung mechanischer Kunstwerke, welche unter der Direktion und Anweisung M. Philipp Matth. Hahn, Pfarrers in Kornwestheim.... Stuttgart: Mezler, 1774.

Von Bertele, Hans.The development of equation clocks.La Suisse Horologere(1959-1961), parts 1 through 5.

Wenham, Edward.Tall case clocks.The Antiquarian Magazine(May 1927), vol. 8, no. 4, p. 33. [The Borghesi clock is illustrated only from a photograph of the Anderson Art Galleries in New York, and mislabeled "Astronomical Clock made in Jena, 1656, in elaborate mahogany case."]

U.S. GOVERNMENT PRINTING OFFICE: 1964

For sale by the Superintendent of Documents, U.S. Government Printing OfficeWashington, D.C. 20402—Price 70 cents

Aristarchus of Samos,54

Bertolla, Alessandro,65

Bertolla, Bartolomeo Antonio,31,34,36,47,51,52,57,62,63

Borghesi, Father Francesco,31,70,71

Brahe, Tycho,54

Butzjäger, Johann Georg,36,37

Charles VI, Emperor of Austria,32

Cles, Baron of,57,59

Copernicus,54

Di Noris, Cristoforo Sizzo,59

Evelyn, John,32

Francis I, Emperor of the Holy Roman Empire,42,44,52,58

Hahn, Father Philipp Matthäus,33

Klein, Father ——,33

Lippi, Fra Lippo,42

Longomontanus, Christian Severin,54

Maria Theresa, Empress of Austria,31,41,42,44,57,58

Meton,48

Monauni, Giovanni Battista,40,52

Philolaus,54

Ptolemy,54

Pythagoras,54

Quare, Daniel,32

Riciolus,54

San Cajetano, Brother David à,33

San Daniele, Father Aurelianus à,33

Sully, Henry,32

Tompion, Thomas,32

Tovazzi, Giangrisostomo,57,58

Williamson, Dowe,32

Williamson, Joseph,32

Winters, Father S. X., S.J.,42

Winz, Johann Christian,36,37

Wisshofer, Peter,36,37

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