The trip to Oris was fruitful, I was able to study the five cogwheels present at the Arjam library and museum and create replicas.
There is only one of these objects missing to complete the picture. To locate it, I studied the (known) history of the artefacts, from the records of the Arjam library. It was part of a cache retrieved by an archeological expedition on Jakri IV, stayed for a long time in the collections of House Or'nold, and was bequeathed to PIE after the last lord from that house died without heirs.
Next step in this research is perhaps not a visit to the Jakri system, but a visit to the Amarr Civil Service administration bureaus for heritage matters. I'll try to find out if the other pieces of this locking mechanism were in lord Or'nold's will, given to other parties.
