Thanks, I had never seen any of those pix in any books.
Regarding the first pic you mention, the pencil inscription on it reads:
"One of the ancient bronze mortars of the time of George II, found at Island No. 10. Formerly at Jackson Square, New Orleans"
So yes, that tells me the South moved a group of similar mortars from New Orleans to Island No. 10, remounted them for service. It would make sense to move weapons of a nonstandard caliber to the same place. The two British Corhorn sizes of that period were 4.5 inch and 5.5 inch, so I'm guessing they intended to use some of their standard shells with specially-made sabots or something.
That's the same thing that happened with the 6" Spanish mortar I've been researching and have posted some info about, it was moved from an exposed location the South knew it could not defend (St. Augustine) to one where they chose to concentrate some force (Fort Clinch, Fernandina FL.) I've checked the more likely parts of the old Spanish records stored in our Library of Congress and easily found dozens of inventories from the 1780's through 1821 that mention the particular mortar. Or anyway it has to be the same mortar, since there were only two bronze mortars in all of Spanish East Florida, one 6-inch and one 9-inch. The 9-inch returned from Washington DC to St. Augustine in the 1960's and the 6-inch is still in a private collection.
If there's any interest in the inventories I could post one. I've never seen any images of them published, although you can see summaries of them in books such as "Artillery Through the Ages." The summary is in a large table about halfway down this page, entitled "Armament...1683-1834"
http://www.nps.gov/history/history/online_books/source/is3/is3c2.htm
