MARTINSVILLE-Have you ever wondered where the cannons at the Historic Henry County courthouse came from? Well, the story involves a West Point graduate, the near death of a U.S. president and a mid-19th century attempt to improve cannon-barrel design.
Thomas Jackson Rodman graduated from West Point Military Academy in 1841, finishing seventh in his class of 52. After graduation, he was assigned to the U.S. Army Allegheny Arsenal in Pittsburg, PA, to serve as ordinance Corps officer. An ordinance officer is charged with making sure that weapons systems, vehicles and equipment are ready and in perfect working order at all times. They’re also in charge of developing, testing, fielding, handling, storing and disposing of all munitions at their assigned post.
It was one of those last assignments that caused Rodman to start working with cannons. On Feb. 28 1844, then-President John Tyler was on board the U.S.S. Princeton, traveling down the Potomac with 400 other guests as the ship’s captain demonstrated the two newly installed 12-inch cannons. One of the cannons, the Oregon, was built in England using what they considered “modern” technology. The second, the Peacemaker, was built using older forging methods. The problem is that while forging allows bigger designs and larger weapons to be built, it also lowers the strength of the barrel, meaning that it can crack and break easier. And while the Oregon had been tested multiple times, the Peacemaker hadn’t and so it exploded during the demonstration, killing Secretary of the Navy Thomas Gilmer, Secretary of State Abel P. Upshur and almost killing Tyler.
As Rodman was in charge of developing munitions at his post, he started to research and work on a new type of cannon, one that wouldn’t have the flaws that caused the tragedy on the Princeton.
The flaw was a critical one. By the early 19th century, most cannons were made of bronze like the one on the Princeton. Bronze barrels were not capable of withstanding the high breech pressures that the larger calibers produced. Most of the barrels were cast solid then bored to the needed caliber. The alternate method was using a sand core and smooth out bore by machining. The casting cooled and hardened from outside, causing stress cracks. It was found in most cases that the boring process did not remove all the cracks, leaving gun barrels weak to higher breech pressures.
Rodman tried to compensate for this problem by wrapping barrels with wire or using bands like iron tire rims used on cannon wheels. Both methods lacked in uniform barrel pressures. Rodman's new modified system of hollow casting replaced the sand core with an insulated iron pipe through which large amounts of water was circulated quickly. The barrel, as it cooled from the inside out, would cause each successive layer of metal to shrink upon the cooler inner layers.
The U.S. Army Ordinance Department was hesitant to approve this process, thinking the design would cause steam to build up and cause an explosion. In 1845, after three trips to Washington and the approval of the Ordnance Department, Rodman entered into a partnership with the Pittsburg Foundry.
In 1849, Rodman produced two 8-inch cannons that were identical in every way except for the method of casting. The conventional cast gun burst after 85 rounds of test firing. The Rodman hollow cast system guns were still firing in good condition after 251 test rounds.
In 1851, six guns on the Rodman principle fired 5,515 rounds and none failed. In 1859, the government approved the Rodman casting process.
On February 6, 1864, Rodman testified before the congressional joint committee. He was asked if he believed smooth bore guns within their range were superior to rifled guns, to which he replied "yes". This answer put him on the wrong side of history on this one issue.
Cannons move on
So what does this have to do with the cannons in Martinsville? During the Civil War, there were several 8-inch cannons or “Rodman guns” installed at Fort McHenry, when the fort was still operational. Those guns remained at the fort for more than 40 years.
In 1901, two smooth bore Rodman cannons converted to 8-inch rifled guns were shipped to the Martinsville train station on Broad Street. The guns were dragged through mud and water by mules to the courthouse square and placed on granite stone mounts, flanking the Confederate statue. Because of weather conditions, this task lasted for about one month.
The cannons have been moved twice more from their original location where they were mounted upside down since 1901. The bores were plugged to keep "want-to-be" robbers from shooting the bank.
These coastal rifled cannons were made at West Point Foundry most likely after the Civil War and restored in 1885. They were placed at Fort Henry, Maryland until 1901 until finding their final resting place in the old courthouse yard. For more information go online to: www.myhenrycounty.com
Information for this article was provided by Johnny E. Nolen and the Martinsville-Henry County Historical Society. The society is located at 1 E. Main Street in Martinsville in the Heritage Center and Museum.