The Failure of French Gunpowder

For any student of military history, it frequently seems that more ink has been spilled over French failures in the Napoleonic Wars than the blood spilled on the battlefield.  This will not stop me, however, from pointing out that the centrally planned economy of revolutionary France resulted in the production of inferior gunpowder that seriously hampered both the French Army and the French Navy,

Gunpowder began as a happy accident in medieval China, when alchemists chasing immortality mixed charcoal, sulfur, and saltpeter, discovering the recipe for very mortal fireworks.  By the 900s, the stuff powered fire lances, bombs, and rockets; by 1044, writers of Chinese manuals were jotting down secret formulas like proud cookbook authors.  The idea zipped along trade routes to the Islamic world, where engineers refined siege craft, and then to Europe in the 1200s, where monks and monarchs promptly asked, “Does it make castles go away?”

Early European “serpentine” powder was a fussy, dusty blend that separated into useless components at the worst moments—think salad dressing with a temper.  Around 1500, makers started “corning” it into grains, giving a more predictable bang for the buck, and handheld guns and big bombards multiplied.  The 1600s brought flintlocks, paper cartridges, and generals who standardized calibers so that cannonballs finally fit the cannon.  In the 1700s, European chemists like Lavoisier tidied French production, while Britain built Waltham Abbey into a gunpowder campus and imported ultra-pure Indian saltpeter by the shipload.  By the time the Napoleonic Wars rolled around, Europe had turned black powder into an industrial science—equal parts chemistry, logistics, and earplugs—setting the stage for continent-wide warfare that flashed—and boomed—from Portugal to Moscow.

From the very beginning of the war in the late 18^th century, the British had an advantage: they imported high quality saltpeter from India.  The French, on the other hand, created a huge domestic program to make and gather salpêtre—building nitre beds (nitrières) per official manuals, and ordering citizens to scrape “nitrous earth” from cellars, stables, barns and rubble for sale to the gunpowder administration. Chemists like Lavoisier/Guyton de Morveau helped standardize and teach the process and authorities used requisitions to keep supplies flowing—so wartime French saltpeter was largely home-produced rather than imported.  The poor-quality homemade saltpeter was hygroscopic—it literally pulled moisture out of the air—not only making the powder less effective but leaving a residue fowled the barrels of the weapons.

To produce the gunpowder, the three ingredients are combined in a process called corning.  In broad strokes, English corning in the Napoleonic era was a tidy, factory-forward affair: mills like Waltham Abbey first compressed the damp “mill cake” into dense press-cakes, then broke and sieved those cakes into consistent grain sizes—an assembly line for bang that prized uniform density and repeatable burn from batch to batch.  The British then polished the powder by tumbling it in a wooden barrel with a small amount of graphite.  This glazing helped prevent clumping and made the powder even more resistant to moisture, while at the same time preventing the buildup of static electricity that could spontaneously detonate the gunpowder.

By contrast, French corning was carried out across a patchwork of state poudreries, but with techniques that varied more between sites: the official instructions emphasize milling and granulation steps, and in the Revolutionary/Napoleonic scramble some works pressed before granulating while others effectively corned from damp cake as equipment and throughput allowed—producing fairly good powder, but with more variability in grain density than Britain’s heavily standardized press-then-corn routine.

There was a significant difference in how the gunpowder was stored.  The British standardized in 25-, 50-, and 100-pound barrels equipped with copper hoops.  The French had a wide variety of barrels, some weighing more than 200 pounds and all them made with iron hoops.  If two barrel hoops bumped together, the resulting spark could ignite all the powder in the magazine.  Perhaps this is why French powder works blew up at least four times during the war.

By the 1790s, plenty of French powder men could see why British stuff went “boom” so politely while French powder frequently either didn’t blow up or blew up prematurely, but the obstacle wasn’t brains…it was bureaucracy.  In France’s centrally-run system, every tweak to grain size, press pressure, or glazing seemed to require a memo to Paris, two committees, and a stamp the size of a wagon wheel.  Nitre inspectors had quotas, poudreries had fixed procedures, and purchasing officers couldn’t just splash out on new presses or hire extra coopers because a clever foreman had an idea: they needed approvals, inventories, and—oops—another approval. Add wartime scarcities and blockade headaches, and even sensible changes moved at the speed of a courier on a muddy road.  Meanwhile the British, who sunk capital into a factory model earlier, could swap dies, retool, and standardize faster than you could say “pass the priming flask.”  The French knew where they wanted to go, but the central planning machinery kept tapping the brakes.  So they made lots of perfectly serviceable powder—sometimes very good indeed—but catching up to Britain’s consistency and scale meant loosening paperwork, freeing procurement, and investing mid-war—none of which a bureaucracy excels at.

The results of this difference in quality were evident in the field.  The French army used a 12-pound field gun.  Due to the increased power of British gunpowder, they achieved nearly the same result with a 9-pound cannon.  Since the British gunpowder produced less fouling, the British army could fire the cannon more frequently than their enemy, while using fewer horses to maneuver the guns. 

For the British Navy, there was an even bigger advantage.  After the Battle of Trafalgar, French captains estimated that because of the difference in powder strength, the British guns could hit targets 15-20% farther than French guns, with a corresponding effect on hull penetration.  The British could score hits while still out of range from return fire.  And when those shells hit, they did more damage than the French shells.  Due to a combination of cleaner barrels and better discipline, British ships fired 50% faster that their French counterparts.

Britain decisively won the Napoleonic Wars.  Better gunpowder wasn’t the only reason, but it contributed.  And the French centrally-planned economy, as it usually does, created more problems than solutions.