LLA 59

APPENDIX 71

BIBLIOGRAPHY 76

[Illustration: Figure 1.--THE DIAL PLATE of the Borghesi clock, showing
the horary and astronomical indications which are automatically
presented.]

_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