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Clockwork investments
In the field of antiques many people
think that the age of an object is the
most important factor in valuing it, but
this is not always so. Take watches, for
example. People often pay more for a
second-hand Rolex than for a 17th-century
pocket watch. This seems perverse to me
because early watches were at the cutting
edge of the technology of their day. I
have one in my own collection that is
dated 1669 and is exquisitely engraved and
pierced in a show of skill seldom seen in
the 20th century. The mechanism does not
work, and the case is badly damaged, but
it is a beautiful object and I love it,
despite the fact that it is almost
worthless.
Even at their best, early watches
seldom kept good time, so most houses and
many public places had larger longcase
clocks, often called grandfather clocks
today. (There is a famous example in the
Pump Rooms in Bath.) With their long
pendulums and their relatively simple
movements driven by large weights, these
clocks were considerably more accurate and
would be used as the standard time from
which you would reset your watch
daily.
A good Georgian mahogany longcase clock
would cost between £5,000 and
£10,000.
Throughout the 18th century,
clockmakers were constantly striving for
greater accuracy. As their knowledge of
the laws of physics grew, so they were
able to devise "regulators" - longcase
clocks that incorporated various technical
innovations. One of the first of these was
the "dead beat" escapement. The escapement
is the part of a clock's mechanism that
makes it tick. You can instantly recognise
a clock fitted with a dead beat because
the second hand advances steadily. On a
normal "anchor escapement" the hand rocks
gently, advancing then dropping back
before advancing again.
Clockmakers aimed to keep the
regulator's movements simple by using as
few moving parts as possible in order to
reduce friction. Each part was machined
with great care. They preferred not to
include a striking mechanism because it
caused an hourly drag every time it was
triggered.
The pendulum, too, was improved. At
first, the rod was fabricated with steel,
but this expanded and contracted in
relation to the temperature of the
surrounding air and interfered with the
accuracy of the timekeeping, so it was
replaced with wood, which was not so much
affected by changes in heat.
Later, bi-metallic strips were used
and, ultimately, weights filled with
mercury, which compensated for changes in
atmospheric pressure and so further
improved accuracy.
Finally, the weights driving the clock
were refined from the crude cast-iron
objects found in most longcases to
brass-cased cylinders carefully machined
to the correct size.
Regulators are usually recognisable by
their simple cases, unadorned but of
first-class materials. A fine Georgian
regulator would cost upwards of
£20,000, but a Victorian example
might be as little as £3,500. One of
the most unusual regulators I have ever
seen was driven by a miniature
water-wheel. The wheel was designed to fix
on to the end of a long shaft that would
extend outside the room where the clock
was housed - presumably in a place such as
a water mill where a constant supply of
water could be provided. It was strange to
see a longcase clock with no weights, but
it did have a wooden pendulum and a
well-machined but simple movement. It is
now installed in the house of a computer
engineer in Silicon Valley. He tells me it
keeps perfect time and, best of all, he
says, it never needs winding up.
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