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.
[Illustration: 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._)]
[Illustration: Figure 22.--INTERIOR OF BERTOLLA'S WORKSHOP, showing
detail of ceiling. (_Courtesy Museo Nazionale della Scienza e della
Tecnica, Milan._)]
[Illustration: 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._)]
[Illustration: Figure 24.--FUSEE CUTTER used by Bertolla. Now in the
collection of the Museo Nazionale della Scienza e della Tecnica,
Milan.]
[Illustration: 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._)]
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.
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 and _grand
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-plate _repoussé_ and gilt with baroque motifs, or upon a smooth
brass plate with spandrels of _repoussé_ work 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 of _repoussé_ copper; gilt was applied to the hands made of
forged steel.
[Illustration: 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._)]
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.
[Illustration: Figure 27.--MOVEMENT of a brass lantern clock made by
Bertolla. (_Courtesy of Museo Nazionale della Scienza e della Tecnica,
Milan._)]
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
items from 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.
[Illustration: 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._)]
[Illustration: 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._)]
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.
[Illustration: 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._)]
[Illustration: Figure 31.--PENDULUM ARRANGEMENT SKETCH for an
unidentified clock found in Bertolla's workshop. (_Courtesy of Museo
Nazionale della Scienza e della Tecnica, Milan._)]
[Illustration: Figure 32.--STRIKING CLOCK SKETCH found in Bertolla's
manuscripts. (_Courtesy of Museo Nazionale della Scienza e della
Tecnica, Milan._)]
[Illustration: 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._)]
[Illustration: 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._)]
[Illustration: 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._)]
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. Bart^{o} Ant^{o} Bertolla"
(I designed and made this clock at my advanced age of 80 years.
Bartolomeo Antonio Bertolla.)
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