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.