this field was apparently
done exclusively by members of the clergy. The earliest was Father
Philipp Matthaeus Hahn (1739-1790) of Wuerttemberg.[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.

* * * * *

[Illustration: Figure 2.--PORTRAIT OF FATHER FRANCESCO BORGHESI,
inventor and designer of the astronomical clock in the Museum of History
and Technology.]

Another of the clerical clockmakers was Father Aurelianus a 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 a San Cajetano (1736-1796) in the same
Augustine order to which Father Aurel