This may be the limber for model cannon. Wonder what was supposed to be in the “cauldron?” Perhaps an early implementation of “liquid propellant.” Or perhaps more likely, an incendiary liquid to be added to hollow projectiles before firing?
I call them “arsenal models.” I don’t have any solid documentation but the ordnance establishments of the more powerful countries seem to have produced one complete, perfectly-to-scale example of the artillery weapons it made for its Army. The materials were the same as in the full-sized version. Such a model, in the days before most workers knew how to use engineering drawings, could help ensure tubes fit their carriages, etc. Well I better stop as I find myself starting to invent parts of this. If anyone has factual info on arsenal models, please share. A few countries have somehow managed to keep their arsenal models in good condition and in one place, most notably France, where you can see hundreds of them in the Army Museum in Paris. I love them but sold most of mine at the auctions of the rest of the collection, in Maine in 2014-5.
I think this one dates from 1860-70 as that’s about the duration of building of rifled bronze guns.