05-06-2005, 07:08 PM
Quote:From the size of the machine, could we not call it a scorpio minor or Vitruvian 2 span machine?
I apologise for resurrecting this thread so late in the day, but I have only just discovered RAT v.2! In my opinion, Kevin has hit the nail right on the head.
The machine discovered at Xanten in 2000 and exhibited recently at Köln is a catapulta, not a ballista. We can be certain that the Romans themselves would never have called it a manuballista, with the important rider that we don't know exactly what they would have called it.
There has been much speculation on what exactly constituted a scorpio in the time of Vitruvius (ultimately without conclusion), but the term seems apt for such a small arrow-shooter as this one. Whether it was hand-held or sat on a stand must remain a moot point.
Incidentally, ancient authors were rather keen on the blanket term tormenta ("torsion weapons"), which the German news sources sensibly adopted.
In advance of full publication, there is little that can be said in a technical vein.
For those not well-versed in ancient catapults, the defining component was the modiolus, conventionally translated as "washer" in English ("Spannbüchse" in German). In summary, every other component in a catapult was measured in multiples or fractions of the modiolus.
This is the crucial dimension because it dictates the diameter of the spring itself.
Thus, although all the print sources so far have quoted the dimensions of the spring-frame itself (the exhibition catalogue quotes 0.26m high x 0.22m wide, while press sources quoted 28cm x 21cm), the crucial dimension is the inner diameter of the modiolus, which (as far as I understand, from correspondence with Dr. Hans-Joachim Schalles of the Archäologischer Park/Regionalmuseum Xanten) averaged approximately 45mm.
For arrow-shooters, the machine was classified by the length of the arrow, which was calculated as 9 times the modiolus.
A modiolus of 45mm gives an arrow-length of 0.40m or (in Roman parlance) 1.8 spans. So, not far short of Kevin's 2-span catapult.
It's worth noting, first, that the spring-frame (from the dimensions quoted) appears to be "oversprung" -- that is, it's taller than it is wide, which has implications for the length of the torsion-springs. Vitruvius recommends that such a catapult should have shorter arms to counteract the effect of longer springs. (The only other known spring-frames, from Ampurias and Caminreal, are "undersprung" -- ironically, we don't have an ideal catapult, by Vitruvian standards.)
The second point to note is that the washers appear to be too large for the frame, judging by the reported dimensions. If the frame is more or less the right width, and was manufactured too tall (i.e., oversprung), the modiolus would have been around 35mm, giving an arrow-length of just over 1 Roman foot (0.3m).
Of course, all of this is speculation until the find is actually published.
It goes without saying that, if any RATers are directly involved in the project, their comments would be much appreciated.
