The Third Object seems to be a mortarium, a dish-like vessel used for grinding in the Roman Imperial period. In function it is much like a mortal and pestle, or a ball mill, and indeed, this object was retrofitted as a ball mill by the magus who owed it: a small sphere of steel which can be commanded to roll or stop by a flick with the finger being added to the object sometime after its discovery in 1223.
It is not entirely clear how it came into Hermetic possession, although it is attested from at least 1251. A magus working on the Isle of Miracles (see glossary*) reports using its ability to neutralise Hermetic magic to make his laboratory work safer. Reagents, if they seemed beyond his control, would be poured into the moritarium, which destroyed them.
This Object is the first known to have been touched with normal vis activiated by mystical work, so it was presumably the first to create succursus. Indeed, when first assessed by a competent scholars, there was a residue of succursus within the Object. It is almost certain that the owner did not recognize the use, or value, of this substance, as the formal discoverer was, of course, the famous Clement of House Criamon.
(*The initial Venetian estates granted to proxies of the Order, informally, to end the shadowy war between the Serene Republic and the more militant houses of the East. Now the headquarters of the Knights of the Ibis.)