If you live near Portland, Maine, you can see two of these 1861 siege rifles at Ethan Allen Park, on a large, grassy knoll overlooking Casco Bay and Fort Gorges. These tubes are really impressive close up; their length is surprising, but we have read that artillerymen back in the day preferred the 4.2" Parrott because of superior ammunition.
The Trench Mortar is interesting because of the munitions it fired. A fairly low velocity launch allowed thinner walls and more explosive. Unfortunately for some WWI Germans, this combo was carried to extremes and some catastrophic failures of these shells happened upon firing.
I saved a picture of one of these a while back with some interesting photo credit info.
Tracy and Mike
This photo is attributed to Ande Lucas of Croydon, Surrey, UK whose great-grandfather, a Saxon Feldartillerie gunner, is shown (on the right in glasses). This pic was posted on the Great War Forum in March of 2008.