The Easter calculator is a self-contained mechanism and
has its own separate weight which runs the calculator when actuated by the
clock once per year. The weight cord was missing when we received the clock
and a close examination of the weight drum and the associated pulleys showed
a square cross section. This is in contrast to the normal rounded 'U'
shaped cross section one would expect with a cord, gut or other conventional
round cross section weight line. Small, regular indentations, more like 'teeth marks' were also
seen on the drum as well as the fact that the attachment point on the drum
requires a chain hook. These observations indicated that a fusee type watch chain
was originally used to attach the weight to the calculator.
The total length of chain needed was close to 20",
(51cm), a bit longer than a typical watch fusee chain. I had purchased a
of chain on-line and Buchanan used these to create the length needed.
Several sections as received were either too rusty or
otherwise unacceptable and were removed. The balance of the chain was then rejoined.
The completed chain is finished. Next the completed length was then tested
The original weight was missing and so a new weight had
to be made and was done in the same style as the clock's main weights. A
rectangular block made of cast iron 2.25" x 1.78" x 15/16". The third photo shows the weight strung
within the wood cabinet base. It would have been more visually interesting
if Pouvillon had somehow made the weight to appear outside the cabinet so
one could see it fall as the calculator operated. However, the size of the
weight as well as the amount of drop needed made this impractical.
The first photo shows the chain wound onto the barrel.
The next two show the pulley set used to direct the chain from the drum to a hole located directly below the outboard pulley where it enters the base
We now deal with the open support areas that are on
each of the collets which support the planets within the tellurian (Mercury
and Venus) as well as the outer planets on the orrery (Mars, Jupiter, Saturn
Uranus, Neptune and Pluto), It appears Pouvillon as late as the 1950's had
not assigned a purpose for these additional mounting points that are located
1800 opposite of each attachment point for the eight planets (Earth
excluded). So why did he create these structures? Perhaps he thought that a
counterweight would be necessary for the planets and later figured out that
it was not necessary. What remains a mystery is why, if this were so he
would not have taken the simple procedure to shave off these points. They
are so prominent as to be a real distraction, and this is especially true
for the two inner planets, and begging the observer to ask
"what is supposed to be attached here?"
We now enter an area where the preservationists camp
will raise serious objections. We have no information at this point what
purpose Pouvillon had for these mounting points. A counter balance seems to
be the obvious answer. So we decided to fill this mounting point with what
could be considered a counterbalance but also add some additional
information in the form of making that counterbalance into a sign of the
zodiac for each planet to which it is connected. At any rate these wires are
easily removed if in the future one wished to do so.
As received the clock was missing all of its planets
and anything that might have been in the places opposite the mounting points
for each planetary collet. The second photo is a close up of the collet
nest. Here the planet wires that hold each of the six outer planets are
present. However, the mounting areas directly opposite each of these are empty.
The first photo is from the 1950's showing Pouvillon
with his clock. One can see first that each planet was mounted on a wire
with a single 900
bend. A careful examination of the area of the photo that shows
the collet nest used to hold the six outer planets reveals that the opposite
mounting points are empty. So at this late date Pouvillon had not seen fit
to use what once was clearly something he had plans for. This photo however
does give us a good indication of the size, spacing and color of the
planets. The next photo shows what was done in 1983, presumably by the Paris
clock dealer Jean-Pierre Rochefort to resolve this problem. This photo is
from an advertisement he had placed in the Antiquarian
Horological Journal at the time. Here he simply duplicates the planets
doubling the number from eight to sixteen (four for the inner planets and
twelve for the outer planets). It also appears that he had
the hemisphere of each planet painted white and black. It is impossible to
ascertain if Pouvillon had done this for any of the planets other than, of
course the Moon.
As received, the two inner planets and the six outer
planets were missing along with their mounting wires. From the photo we have
of Pouvillon we knew how to recreate the planets has he had originally
intended. However, what do we do about those empty mounting points? Since
the decision was made to utilize these, the question became "in what manner?"
I rejected outright Rochefort's option. It seemed to me artificial and
completely confuses the viewer as to the correct position of the planets. The
first illustration, and we only deal with the outer planets in these, shows an option where we substitute the duplicate planets
with zodiac indicators for each planet, but basically keeping with the same
design as initiated by Jean-Perrie Rochefort. This would have been little
better than Rochefort's design as to the clutter added to the orrery. A
second option was to lower the zodiac indicators to the level of the
zodiacal ring. I considered this because I wanted to use the ring as a
reference point for the planets. However this option was rejected because
the indicators would be too far from the ring to be of any use.
One way to make the indicators very useful would have
been to alter the design of having each planet connect to the collet nest by
a single 900
bend and substitute three such bends as shown in the first
illustration. A close indicator pointer would have been ideally positioned
near the ring. Of course this would have resulted in a major change from
what we know Pouvillon had designed for the orrery and so this was rejected.
The next illustration shows the solution I decided upon which was to have
each zodiac indicator mounted to a horizontal wire, and laying flat in the
horizontal plane. In effect, pancaked above each other as illustrated by the
small green lines. In this way we avoid
the clutter of Rochefort's option and we use the empty mounting points with
on option that utilizes the information on the zodiacal ring to plot the
position accurately with the zodiac, albeit at 1800
opposite to each planet. These can also be considered as
counterweights. I think the video below will reveal this as the best option.
This completes the restoration of the
mechanical components of the Pouvillon astronomical clock. It is now
completely functional and all of the original and missing components and
functions are complete and operational. The remaining issues are
non-mechanical in nature and will be described in a later chapter.
The video below shows a demonstration of the orrery
showing the planetary zodiac signs positioned near the lower zodiac band.
Observe how these make reading the position of the planet very easy in
relation to the band as well allowing the viewer to know where a planet is
in each zodiacal house as well as showing when the planets are in conjunction.
Note that the Earth /moon system is not in motion during the demonstration
as one would expect. This is because those are driven by the time train
while the balance is driven by the strike train. It would have been very
difficult for Pouvillon to have merged these two separate systems for the
purposes of a demonstration. For those who cannot use the built-in viewer on
the left, please click on the YouTube video to the right.