Ducal palace at Charleville-Mézières. The city, located on the banks of the Meuse River, is a commune in northern France and capital of the Ardennes department in the Grand Est region. Wikimedia.
Duportail was appointed second lieutenant (lieutenant en second) on January 1, 1762. Two naval engineers who were admitted on their titles denounced him and some friends in February 1763. They opposed the admission of students of doubtful nobility to the school. One of the accusers was the son of a postmaster who barely escaped bankruptcy. The other was the son of a merchant who still bore the social stigma of a bankruptcy. As a result of the anonymous accusation, Duportail and two other “ringleaders” were separated and sent to prison for one year in March 1763: one to Ham, another to Sedan, and Duportail to Bouillon Castle in the Luxembourg province of Belgium. All the students at the military school decided to join their fellow students in prison. After completing their sentences, the three students were exonerated by the king and readmitted to the school at Mézières. An inquiry later revealed the allegations were totally unfounded, but Duportail benefited from his time in prison by reading and studying military science at a high level, which advanced his career.
GRADUATION AND ASSIGNMENTS
Louis Duportail graduated as a regular engineer in 1765 at the age of twenty-two. He served two years with the infantry at Bayonne and Marseille, working pretty much as a modern engineer does and learning much through the communications with the authorities who employed him. He continued studying, edited memoirs, evaluated costs, and made maps. He had assignments at Strasbourg (1769); Gex (1770), where he was dismayed by the useless works at Versoix (a village on the Swiss border that the Duc de Choiseul wanted to fortify); Montpellier (1771); and Metz (1774). He was promoted to captain on August 25, 1773, at the age of thirty. He was assigned to Aire in 1775, then to Bethune in 1776.
The Comte de Saint-Germain, the minister of war, summoned him on July 15, 1776, to prepare a new edition of a training manual for the Royal Corps of Engineers. It was to contain every bit of knowledge that an engineer needed to know and to reflect the changes being instituted in the military. Duportail proposed reducing the number of officers from 400 to 329 and the number of fortifications from 20 to 12. He also recommended basing promotions solely on merit and organizing internships to complete the course of training. The manual was published on December 31, 1776, just as Duportail was beginning his negotiations with Benjamin Franklin.
NEGOTIATIONS WITH FRANKLIN AND DEANE
Duportail was recognized and appreciated for the quality of his work, just as he was for the memorandum that he wrote for the minister of war in December 1773, in which he proposed a complete organization of the engineers. The manual was poorly received by the engineering officers, but his minister greatly appreciated it for its intellectual discipline and strength of reflection and his ability to analyze and synthesize. The Americans later translated it and used it to organize their own Corps of Engineers.
When Benjamin Franklin arrived in Paris in December 1776, he informed the Comte de Saint-Germain that Congress wanted him to “secure skilled engineers, not exceeding four,” who might serve in the Continental Army. The minister of war agreed to this request if it could be done in secrecy, without arousing the suspicions of the British ambassador, whose ubiquitous spies kept him informed. Saint-Germain suggested that Duportail go to America and authorized him to deal directly with the American agents. Duportail quickly agreed and was admitted into the Royal Corps of Engineers with the rank of lieutenant colonel.
Silas Deane, however, did not take the necessary precautions to adhere to the strict and precise demands of Congress. He was immediately besieged by many candidates whose qualifications he would not take the time to verify. One of them particularly impressed him: Philippe Charles Jean Baptiste Tronson du Coudray, the pretentious duc d’Artois and former tutor of the king’s brother. This theorist of artillery authored several books on the topic, such as L’artillerie nouvelle et L’ordre profond et l’ordre mince considérés par rapport aux effets de l’artillerie. He was an expert on making gunpowder and on metallurgy for canons. He also had access to the arsenals and promised to supply 200 pieces of artillery; material to clothe 25,000 men; and 12 engineers, 4 captains, and 4 lieutenants to satisfy Deane’s needs.
Du Coudray’s application was quickly accepted with great enthusiasm, and Deane wrote a letter to the Secret Committee of Correspondence of Congress, in which he specified the reasons for his choice: Du Coudray would secretly recruit engineers and, on Vergennes’s recommendation, contact Beaumarchais about his operations for recruitment and reinforcement. Beaumarchais would then ship the promised armaments and equipment through Roderigue Hortalez et Cie., a new trading house, which would essentially act as a front for the French government. Deane concluded an official agreement with du Coudray on September 11, 1776, in which he promised him the command of the artillery and the future Corps of Engineers. Every plan or project related to the fortification and artillery would then be submitted to du Coudray for his approval before execution.
However, du Coudray’s plans soon became known to his superiors and risked compromising the secrecy that the king wanted concerning aid to the colonies. Du Coudray was recalled to his garrison at Metz, but instead of complying,
