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Proposed designs to restore the zodiac precession, the year indicator ring, the orrery demonstration crank and replace orrery planets and their counterweights

I have asked Buchanan to provide what I call a 'forensic' report. That is to record his observations as he goes along. I will provide the .MP3 audio file for each segment but just in case your security settings will not allow you to open this file I have also transcribed each session. Buchanan refers to each photo by the number of that photo which can be followed by each photo above the captioned text. The .mp3 audio file will appear in blue text.MP3. Click on this text and you can then follow along with the audio file by scrolling downward through the photos as they are narrated one by one in the voice of the restorer.

There is strong evidence that three complications which are currently missing were present within the original movement. The first is the precession of the zodiac which occurs over a very long 25,806 year cycle. The second is to replace the missing year indicator ring, and the third is the ability to manually demonstrate the orrery in fast speed.

Below we show our proposed designs to recreate the parts needed to restore these complications that we believe the Pouvillon clock had originally. Next we turn to replacing the missing planets in the tellurian and the orrery. Finally we explore, pending any further information, what Pouvillon may have used the extra attachment points on the tellurian and orrery for.


We now turn to the restoration of what we believe are the missing components for three complications. Here we have Buchanan’s design for the first complication, the lower zodiacal ring to rotate once per 25,806 years to give the indication of the precession of the zodiac. In a 1953 Paris newspaper article Pouvillon states that the zodiacal ring is made to rotate, through a set of twelve reduction wheels, once per 25,806 years. This is again repeated in an article for the Association Nationale des Collectionneurs et Amateures d’ Horlogerie Ancienne (ANCAHA) in the 1985 Summer issue written by Bernard Miclet. There is no doubt that the lower zodiac is designed to turn, and when measured against the fixed upper ring which is calibrated in markings to make up 3600, would readily lend itself to this function. There are a few open holes where such a system could have been mounted. 

Here we have a dilemma. In the few photos we have to date, all of which were made after the death of Mr. Pouvillon in 1969, there is no evidence of this wheel work being present. Did Pouvillon actually complete this function, or was this never attempted or completed?  We propose to recreate this function and use only those holes that are currently open to attach the wheel works. Nothing of the original artifact will be altered and everything will be fully reversible.

Our system is designed to be completely hidden beneath the zodiac ring since we have no evidence so far of how or if Pouvillon made this. We also use twelve wheels to achieve the required reduction. All wheels will be made in the manner of Pouvillon’s own wheel design.

This diagram depicts our design to recreate the second missing complication component which is the calendar ring year indicator in the tellurian dial. In Janvier’s tellurian, which this certainly was at one time, this indication was shown as a set of numbers from ‘00’through ‘99’on an annular ring and seen through a small square aperture in the porcelain dial just after the month of January. On the dial there is already a ‘1’. Followed by the aperture. In Janvier’s unaltered tellurian, of which we have good photos, there was a ‘1’ followed by an ‘8’. The one is fully backed onto the enamel in the same fashion as all the other black lettering, but the eight looks to be much lighter, almost as if it were removable. This would make sense as that tellurian was made around 1790 and if the seven had been permanent the year indication would have been good for only ten years. The square aperture is now filled in and all evidence of the annular ring is missing. It seems that Pouvillon was anxious to cram as many complications as he could into his clock and this complication is not duplicated anywhere else in the clock. It would seem that he would want to preserve this indication. So, absent evidence to the contrary, we propose to reinstate this. For more on this complication and the history of the origin of this tellurian see the August 2011 installment. A discussion about the origins of the tellurian assembly. As stated before, this will be fully reversible with no permanent changes to the artifact.

Both of the proposed reinstated complications discussed above must somehow be driven. The zodiac ring could be driven by a direct gear connection. The calendar ring, however, must be stepped, or ‘clicked’ once per year so the correct number appears in the aperture window immediately and stays there until the next annual change is needed. A direct gear connection to the zodiac is not possible without alterations so we opted for both of the systems to be stepped. For the zodiac ring this makes no difference due to the extremely slow rotation. In fact it’s unlikely one would notice any movement within one’s lifetime. The long arm below the mechanism extends rightward, beyond and below the zodiac ring and turns upward a small distance just beyond the ring’s perimeter. This small ‘paddle’ engages, or is pushed by the pointer which indicates the zodiac sign and is located opposite of the pointer which is below the Earth on the tellurian that reads the degrees on the upper, fixed ring. Therefore, as the tellurian boom swings past the paddle each year, this mechanism will step both the zodiac and calendar rings.

I had two problems with this design. The first was the fact that we have no evidence of any external paddle being used. Secondly, the zodiac pointer will have to be beefed up to do its job of pushing the paddle lever, a change to the artifact as I’m convinced that this pointer is original.


This is an alternative to the stepping mechanism described above. Here we eliminate the external paddle lever. Instead the stepper is driven off the uppermost planet’s arm as it swings around; that planet being Mercury. Shown here are the wheels necessary to convert Mercury’s annual rotation of 0.24 years to an annual step for the calendar ring. The feed to the zodiac ring remains as in the prior diagram. There may be a bit of evidence to back up this design. In the one photograph we have of Pouvillon with his clock, and it is a poor one to indicate detail, we can see a small bit which could be a pin to catch the arm of Mercury. Again, barring new evidence all is just conjecture at this point. See blow up of photo section. In this enlargement there is definitely something there below the zodiac ring that is no longer present and could have been something used to drive the zodiac precession.



A careful examination of the base plate supporting the orrery superstructure showed witness marks where two cocks were originally mounted (1 and 2). In addition there was a space below the orrery drive pinion where an additional part was mounted to that arbor (3). Using this information we will restore, again without any alteration to the clock as found, the demonstration winding crank assembly for the orrery. Pouvillon created this clock as an advertisement for his skills. He certainly would not have missed the opportunity to have has a stunning demonstration of his orrery. These diagrams show the proposed system. Since the orrery is driven from the strike train, the crank will disconnect the orrery from that train when the winding key is inserted and while the orrery is in the demonstration mode and then reconnect the orrery when the winding key is withdrawn.

Pouvillon-65-001.MP3. Photo 65 001. This series of photographs shows the procedure in making the ball joints for the elbow joints for each of the planets on the orrery. Here we have a brass rod held in the collet on the lathe and we’ve reduced it to the overall diameter of the ball. Photo 65 002. Here we have the ball turning attachment fitted the lathe and preparing to take out first cuts. Photo 65 003. Our first cut starting to produce the actual ball for the joint.

Photo 65 004. We have the ball turned complete and we now have to machine the actual parallel portion of the stem. Photo 65 006. Here we are machining the parallel portion of the spigot on the ball. Photo 65 007. Busy parting off the ball and its spigot from the parent material. Photo 65 008 are the finished balls with their spigots.

 Photo 65 009. Here we’re holding the ball by the spigot in a collet in a vise and at the top of the picture you’ll see the drill bit ready for drilling the hole to produce the vertical support for each planet. Photo 65 011. Here we’re about to drill the hole for the vertical wire for the planet. Pouvillon-65-019.MP3. Photo 65 019. You can see a split collet to hold the ball with the end of the spigot projecting out the front of the collet. This is placed in the lathe in a larger collet which enables us to hold the ball by the spigot without damaging our nicely turned sphere.

Photo 65 020. Here you can see the split brass collet in the main collet on the watchmaker’s lathe and the end of the spigot projecting ready to have the center hole drilled in it. Photo 65 021. About to start drilling the hole for the horizontal wire that supports the whole arm. Photo 65 024. We have two pieces of wire inserted into our elbow joint.

Photo 65 025. The completed elbow joint and the seven extra balls for the other planets. These will later still be reduced in size to make them less heavy looking.

We now turn to the making of the planets for the tellurian and the orrery. From the one photo we have of the clock before Pouvillon’s death it looks like all of the planets were made of a white material and given the time of manufacture we believe these were probably made of ivory. A source of legal elephant ivory material was located and is used for the planets as well as the winding and orrery demonstration key handles. We have recreated these to the same size as we could best determine from the one existing photograph.

The first photo shows the initial line up of the planets and their relative sizes as compared to the ruler. The next photo shows the initial setup. The next first photo shows the elbow we used for the planets.


These two photos show the planets as we were best able to determine Pouvillon would have designed them. Notice in the second photo that there still is an empty attachment point opposite each of the planet’s attachment points on each of the orrery collets, see arrow. We believe that these empty attachment points could have been used for a counterweight to the planets. The problem is that this same design is used for the inner planets where there would be no need for this. Therefore, we have decided to again design a use for these that are totally reversible and have no effect on the original artifact.

The next several photos show what we decided to use the empty attachment points available on all of the planet collets for. These would indicate the zodiacal sign for each planet and these signs would be read off of the zodiac dial to better determine the planet’s position within the zodiac, see red arrow. The interesting thing about this arrangement is that one can use the positions of the planets within the zodiac as well as the sun’s position as depicted by the tellurian to make predictions based upon astrological rules. 

The paper squares represent the planet zodiacal signs as they move through the zodiac as depicted on the lower zodiac ring. The next photo shows an overview of this. The next photo shows the initial design for the planetary zodiac sign next to the trial paper models. Note how each zodiac sign has a tear drop shape with the point toward the zodiac ring.  


                                        The video shows our initial trial demonstration of the orrery with its newly mounted planets

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