The two cannons in the back are the patented R. P. Parrott rifled guns, produced in the West Point Foundry in Cold Spring, NY, named by George Washington after the water found there. The “band” around the breech plus the rifling and newly designed artillery shells to go with them, i.e., a brass “sabot” at the base of the shell to impart spin, gave them twice the range of some of the “smooth” bore weapons here in the foreground at Peebles Island, Waterford, NY a New York State Historic Park. They are becoming rarer, one I know in Farmington, New Hampshire another in Trenton, New Jersey, that its citizens bought after the Civil War, the so-called “Swamp Angel”. In 1863, from a swamp outside Charleston it bombarded that city a number of times with incendiaries as described in a poem by Herman Melville and others, before exploding making it useless and then investigated by the Franklin Institute in Philadelphia, PA later purchased by citizens of Trenton, NJ. It is the first use of those weapons on a civilian population in modern times.
Various calibers of “Parrott Guns” were made and fired projectiles, "...from about 10 to 300 pounds..." and were often on mobile gun carriages and caissons. “Some 3,000 cannon for Union armies were manufactured at the West Point foundry…” (from a caption to a black and white reproduction of a famous painting by J. F. Weir of the foundry while casting. In “The American Heritage Picture History of The Civil War” (Bruce Catton, c) 1960, pub. 1982 Bonanza Books, American Heritage, Inc., a division of Forbes Inc., p. 393) it's the only entry for the foundry in the index of this large tome (630 pages) and starts the chapter "Two Economies At War". There is other info in this poster “Lincoln at West Point Foundry”). The West Point Foundry has also been noted as having had the first "labor action" in a "Federal facility". They also had offices in New York City and some of their ships set speed records to West Point, a trans-shipment point for the foundry. Casting sand, called “green sand” came from a source nearby.
One of the first long-range shots at the CSS Alabama off Cherbourg, France, where it was then sunk by the USS Kearsarge and Great Britain subsequently fined millions in Switzerland for allowing it to be built against treaty, was from a smaller Parrott gun which struck the notorious ship raider below the waterline.
Currently there appears to be some rancor across the Hudson River over a cannon there a British built 10” breech-loading Armstrong, on exhibit, which some think inappropriate, considering all the weapons made in the Confederacy, towards the end, some even copied R. P. Parrott! I worked on the EPA remediation of the Foundry Cove where we found the prototype of the about 13 foot square wooden gun-platform on grillage used for a “Swamp Angel” under the 20th century concrete stanchions, the remains of the Chicago Bridge and Iron Co.’s over 500 ft. long “Bridge Shop” where structural parts were assembled on rail, riveted together and painted. One railroad "swing bridge" was ca. 1990, still in operation in New Jersey. It might be more appropriate if at a request to the citizens of Trenton, NJ, the real “Swamp Angel” was put on exhibit at the West Point Military Academy, not the efforts of others but of the foundry just across the Hudson River to the east, some who were apparently given pseudo-identities and had clandestinely left Great Britain to work in the foundry, according to more recent research on file in the Foundry School Museum in Cold Spring, NY.
Three Parrott guns like these are also stood as a tripod, pointing at the sky, with "cannonballs" on their muzzles (not used in them, shells were) as a memorial to General US Grant at the cemetery at the Shiloh Battlefield (Flickr picture here Shiloh National Military Park, US NPS) also known as the battle at Pittsburg Landing in Tennessee. Nearby over the Mississippi border, I worked in archeology in the summer of 1979 on the Tennessee-Tombigbee Barge Canal for Soil Systems, Inc. and the Army Corps of Engineers.
Note: for a somewhat anthropological look at the origins of the “Civil War” also seen in my opinion in the West Point Foundry archaeology, see the Wikipedia entry “Tuckahoe-Cohee” though, the brou-ha-ha over the construction of the U.S. Customs House in Charleston, South Carolina, I feel, had also something to do with it. President Lincoln spent over $1 million on a replacement dome for the United States Capitol during that war, made in the South Bronx by Janes and Kirtland and assembled by them, New York City based cast-iron fabricators.
West Point Foundry Cove, Cold Spring, NY ca. 1989
From the initial clearing and survey of the Cold Spring, NY EPA Superfund Site (Marathon Battery) archaeology testing by Grossman and Associates, Inc. Added: "Found here the buried loci of foundry test rail end, R. P. Parrott's gun platform and range tower." Scanned discarded AutoCAD map I "drew".
Update 9/25/10: A lot of underwater work has gone on at the CSS Alabama wreck site off of France since I worked in the Cold Spring, NY vicinity with Gordon Watts, East Carolina University (since PhD, from St. Andrews of Scotland, a belated congratulations) who had discovered the USS Monitor wreck on a North Carolina state survey and last I had heard was working with the French on the preliminary assessment of the CSS Alabama site. Here is a recent YouTube video of “The Naval History and Heritage Command Underwater Archaeology Lab Artifacts” from the CSS Alabama and the USS Tulip. Amazing work by the DoD.