18th Century Mortar
After two losing campaigns (D'Artaguiette's Northern Force and Bienville's Southern Force Musings) against the Chickasaw in 1736 one would think that someone in charge would make a different plan of attack against the Chickasaw forts. Governor Bienville did, at least he said so in a letter to Maurepas dated September 1736. He asked for a specific weapon and a specific size of that weapon, "We ask for two small mortars of brass, each of which can be carried by two men or on a horse and which can throw bombs weighing 20 pounds," see MPA I 322.
What is a mortar? It is a short barreled piece of artillery that fires a bomb at elevated angles. The intent of the mortar is to lob its bomb over a wall or in the case of the Chickasaw over the walls of their forts. Bienville's request is for small mortars made of brass. Why brass? Avoid corrosion due to high humidity and temperature, both of which increase the rate of oxidation of more typical and cheaper iron mortars. The request further asks for small mortars that can be carried by two men or a horse. Why? To fight the Chickasaw you have to go to their villages which are hundreds of miles from Mobile or New Orleans.
Why did Bienville not ask Maurepas for cannon? Two answers: 1. Canon were not effective in 1730 when the French were trying to dislodge Natchez from two of their forts after the 1729 Massacre at Fort Rosalie (Natchez, Ms), see MPA I 134. The issue with cannon vs the Natchez Indians was Cannon fire at low trajectory and tend to be a battering weapon. The Natchez Forts were not damaged by the French canon. 2. Cannon are more massive compared to mortars and thus more difficult to transport.
The bombs of a mortar typically have a fuse so that the bomb explodes in the air before it strikes the ground. Why? In short, the bomb is an iron sphere filled with gunpowder. When the fuse reaches the gunpowder in the bomb, the explosion fractures the bomb into many missiles. It is a fragmentation weapon. So women and children or horses inside a fort would be terrorized by the noise of the exploding bomb and wounded or killed by its fragments.
The above is a video of a small 18th century mortar. The mortar is fired by reenactors from the Battle of Yorktown. The mortar in the video is four and one-half inches bore (diameter) and fires a nine pound bomb.
Although it is small in the mortar world, it is not a toy. This size of mortar and bomb would have been effective against the Chickasaw forts in 1739-40, if the French could have gotten it there. You would have needed several mortars and several hundred bombs to rout the Chickasaw from their forts, and an expert bombardier to fire the mortars. As far as size of the forts I would say one hundred feet by one hundred feet would be about the right size for a square fort only native peoples' forts were typically reported as oblong shaped. After D'Artaguiette's campaign reports were the forts were embedded posts making outside walls with no interior. Joseph Chauvin de Lery who visited an abandoned Ackia in 1737 said that all of the four forts of the small prairie had fortified cabins within the outer walls, see MPA III 702-4.
Did Maurepas send small mortars to Bienville for the 1739-40 campaign against the Chickasaw? Did Bienville fire them against the Chickasaw forts? Stay tuned…I will add material this summer to Bienville's Revenge Musing.
For your convenience here is a link to Mississippi Provincial Archives, French Dominion I-III (MPA) also provided in earlier Musings.
Regards from Tupelo,
Steve Cook
May 16, 2022