I bought this on eBay.
Back story: Dug up in France (adding the cachet of buying an illegally exported element of the cultural patrimony to the exercise ) evidently somewhat recently.
45" o/a. approx. 1.5" bore.
Dated to the "early to mid 1700's" and described as "a signal or salute cannon".
I don't think so. If my understanding of ordnance is accurate, small cannon such as this would have been yoke mounted at that time (ie. trunnions emanating from the sides of the barrel). As you can see it has a tab that fits into a yoke below the barrel. I saw some closeups of the pivot thing and it does not look to be slapped on recently, so that appears to be the original mode of mounting. Also, swivel guns of that era were short. 24" or so. This long (relative to caliber) thing seems to me to be considerably earlier. I'd sorta guess at least 100 years earlier.
I've seen illustrations of similar kinds of tubes with similar kinds of mountings that were described as "garrison guns" or somesuch.
Any thoughts on what it is or when it was made?