A HISTORY OF GUNPOWDER
This is the stuff we all use to make our reenactments go with a bang! It was originally created by or revolved in China. Studies carried out in the late 1800's found that 500 years of experiment by thousands of craftsmen had hit on the ideal mixture for making gunpowder (black powder) - 75% saltpeter, 15% charcoal and 10% sulfur. This was found to be the scientific ideal for the most powerful explosive. For some reason alderwood makes the best charcoal for gunpowder.
Once ignited, gunpowder burns at 2138 degrees centigrade. The intensity of the heat adds to the explosive effect by causing the resulting gases to expand rapidly. That's why your musket barrel gets hot during a battle! Solids make up to 56% of the results of the combustion, showing up as smoke and the deposits we all struggle with on the inside of the gun barrel. Carbon dioxide, nitrogen and other gases constitute 44% of the by-product of firing off gunpowder. These gases, at normal pressure and temperature, occupy 280 times the volume of the original powder. At the start of the reaction of ignition, they take up about 3600 times as much space, generating a pressure of more than 20 tonnes per square inch in a closed vessel.
To get a sense of the scale of the expanding gas, imagine a yard stick representing the solid powder stretching almost instantly to a length of 2 miles, representing the amount of gas generated. Gunpowder converts all its potential energy to hot, expanding gases in a few thousandths of a second.
In a cannon, a good portion of the chemical reaction takes place before the ball has a chance to move. The hot gases acts as a powerful spring coiled between the 12 lb projectile and the breech of the gun. Because the ball was far lighter than the massive gun, its springs forth with the greatest velocity though the cannon receives a formidable recoil jolt as well. Once the ball starts moving, it travels the length of the barrel in barely 10 thousandths of a second - the blink of an eye lasts 9 times longer. It has gained all of its velocity during this brief acceleration. Once it emerges from the end of the barrel (along with the blast of expanding gas smoke and flame) it continues on its way with enough momentum to carry it a mile or more. In the early 1700's experiments were carried out to determine the actual speed of a musket ball as it left the muzzle. This was calculated at 1139 miles per hour. Modern studies confirm that projectiles from both muskets and cannon of the era did have a high initial velocity, probably between 1000 and 1200 mph. This of course is less than half the speed of a modern rifle bullet, but considerably faster than the 750 mph velocity of sound. Because of drag and gravity, and the aerodynamic properties of a ball, the projectiles lost half their speed during the first 100 yards of flight. Investigations in 1742 showed why muskets were so inaccurate. The Experiment was to clamp a musket in a rest and measure its performance by firing through paper screens set at 50, 100 and 300 ft in front. By the time the ball reached the middle screen it was off a straight line of flight by 15 inches. At 300 ft the deflection could be up to 6ft.
Quite apart from inaccuracies in manufacture, and wear and tear on gun barrels, the major reason for this inaccuracy was 'windage'. The musket ball span because the sphere was made to fit somewhat loosely down the barrel. The gap between the projectile and the bore - windage - eased loading and provided a measure of safety if breech pressure became too high. With the push of the exploding gunpowder, the ball glanced off the inside of the barrel here and there as it travel's towards the muzzle. The last point of contact determined the speed and direction of its rotation. Since both were unpredictable, the ball's path from one shot to the next could vary widely, veering right or left, lifting or sinking. Rifling, and then cartridge ammunition post the American Civil War, were to radically solve these problems, but in 1814 a British Colonel said 'at 200 yards with common musket, you may as well fire at the moon'. In a 1742 battle, Prussian forces fired 260 rounds for every Austrian killed. Lack of accuracy was the overriding trait of gunpowder weapons during most of their history. During the English Civil War in the 1600's, a royalist Colonel condemned to death beckoned his firing squad to come closer, for fear that inaccurate shots would botch the execution!
On New Years Day 1800, the American Eagle docked at New Port Road Island, sails torn hull leaking and food supply exhausted. The ship had taken 91 days to cross the Atlantic, a month longer than Columbus had spent making the same trip three centuries earlier. The ship brought the DuPont family as emigrees from France. Soon they were to set up a gunpowder mill on the Brandywine Creek near Wilmington, Delaware. By 1804 the plant was in full production. Starting the business during the Napoleonic Wars was propitious as the business boomed. DuPont used rollers to produce a larger volume of more homogeneous powder in a shorter time. The gargantuan wheels saved considerable labour and for fine rifle powder wheel incorporation took about 4 hours. Pressing was another change that contributed to the more powerful gunpowder of the 19th century. Worker shovelled the incorporated powder (known as 'mill cake') from beneath the wheels into a box and applied a force of 1200 lbs per square inch pressure using a screw press. The slightly damp powder was squeezed to roughly half its former volume, forming 2ft square slabs of 'press cake' with the hardness of slate. This pressed powder was considerably denser than the ordinary corned powder a smaller amount of explosive packing more punch. The press cake was put through a series of rollers and sifters, which sorted the granules of powder by size. Standard musket powder was classified as F grade. Finer powder used for rifles was designated FF or 2F. Still finer grades used for pistols and as primer powder were classified 3F and 4F. As a last step, the gunpowder was tumbled in glazing barrels. Hours of agitation rounded the edges of the grains increasing the powders durability. The finished grains of rifle powder had the consistency of granulated sugar, whereas those of cannon powder were the size of uncooked rice kernels.
One other significant advance increased the force and consistency of 19th century gunpowder. Instead of burning charcoal in earth covered pits, manufacturers distilled it by heating wood in closed iron retorts. By carefully controlling the temperature, workers could influence the explosive qualities of the powder made from this charcoal. The kiln charcoal produced gunpowder that was both stronger and more consistent than earlier versions.
The same year that the DuPont family was landing in the new world, and English chemist named Edward Howard presented a paper to the Royal Society in London describing the preparation and properties of mercury fulminate. The compound had a quality that distinguished it from almost every other known chemical: it was highly explosive. It didn't even require a match to set it off - a sharp concussion was sufficient. So you can see now where the ingredients and methodology of the ACW gunpowder and percussion caps come from, together with the rifle musket. It was a Scottish Clergyman, Alexander Forsyth, who, keen on wild fowling, used fulminate 'scent bottle' system to set off sporting muskets reliably in any weather condition. It was around 1814 that a little copper top hat, charged with fulminate fitted onto a hollow nipple projecting from the top of a gun's powder chamber, came into use for the first time.
Once the new system proved reliable, armies began the rather simple procedure of converting flintlocks to the fulminate-fired weapons. Troops could fire at a faster rate, drill was simplified and wet weather no longer turned a firearm into a club. Percussion ignition made practical the revolver, the breech loading rifle and the repeater, further multiplying the fire power of a single soldier. The simplicity of the percussion system compared to the flintlock eased the transition from hand made to mass produced firearms.
In 1823 a British Officer named Colonel Norton stationed in South India observed natives shooting blow guns. He described how they attached to each dart a round disk of lotus pith. When they blew into the mouthpiece the pith expanded sealing the tube and accelerating the projectile. French captain Claude Etienne Minié of the Chausseurs d'Orleans took up this idea to solve an ancient dilemma. Infantrymen had been forced to choose between the quick loading inaccurate musket and the slow precise rifle. Minié designed a conical bullet narrow enough to drop easily down the bore, but with a hollow base that widened with the blast of the powder. The bullet caught the grooves of the guns rifling, which imparted spin to the projectile. Besides taking advantage of rifling, Minié's elongated bullet presented a more aerodynamic shape to the air and therefore encountered less resistance, and also tended to seal the bore as it came out, thus diminishing considerably windage. This bullet was therefore able to translate the explosive force of gunpowder into hitting power at the target with less energy loss, increasing range and accuracy.
At the start of the American Civil War DuPont works turned out nearly half the nation's gunpowder. The main obstacle facing DuPont as he prepared to meet the enormously expanded demand for gunpowder was a shortage of saltpeter. The US imported most of this key ingredient from India through British dealers. The DuPonts immediately cornered the market by, in a single day in November 1861, buying every ounce of saltpeter that was available in England and contracted for further shipments direct from India. In all they acquired 3.4 million pounds of this vital commodity!
By 1863 saltpeter was again running low and the price of Indian saltpeter had gone through the roof. DuPont's chemists devised a method to convert Chilean saltpeter which was predominantly sodium nitrate to the potassium nitrate needed for gunpowder. The new chemical processes thus introduced greatly speeded up the production of gunpowder, and was the birth of a chemical industry.
Whilst the North thus had good supplies, the South had real problems. Jefferson Davies put George Washington Rains in charge of the Gunpowder and Niter Bureau. As ever the Confederates struggled to get raw materials, but Rain's Guide was a pamphlet written by a British Artillery Officer describing the up-to-date British Government Powder Plant at Waltham Abbey in North London. With advice from a man who had once worked at the mill, Rains oversaw the construction of the most modern powder factory in the world at Augusta Georgia. He laid out the plant for efficiency, with the raw materials entering at one end, passing through each step of the process, and emerging as finished powder a mile and half down the line. Once the plant was running at full capacity, it ground 3.5 tonnes of powder a day or 2.75 million pounds over the course of the war.
Whilst potassium nitrate had long been recognized as the ideal ingredient to provide the oxygen that turned the combustion of charcoal and sulfur into an explosive deflagration, its drawback was cost. Lammot DuPont (1831 to 1884) investigated ways to use sodium nitrate to make serviceable gunpowder. This was dirt cheap being bird guano from the coastal regions of Chile. Its serious disadvantage was that it readily absorbed moisture making the gunpowder damp. By 1857 he had patented an 'improvement in gunpowder' it was the only fundamental alteration to the traditional formula that proved practical over gunpowder's long history. Having ground sodium nitrate sulfur and charcoal together in the usual way, he tumbled the resulting grains with graphite for a full 12 hours. The graphite formed a coating that dramatically reduced the tendency to pick up moisture. However one characteristic of this new gunpowder was that it was no use in guns and for the first time in history a variety of gunpowder had been formulated that was only useful in blasting tunnels working mines and other civil engineering tasks.
The American Civil War was at the cusp of military technology. It was in 1864 that Alfred Nobel patented a blasting charge made from nitroglycerin. The next step forward was to get rid of all the smoke when guns were fired. During the 1880's French inventor Paul Vieille became the first to find a way of plasticizing gun cotton by mixing nitro cellulose with a solvent of ether and alcohol. When it burned it created little smoke or residue. Vieille had thus invented 'smokeless' powder known as Poudre B, and he brought it to the market in 1886. Nobel developed a rival propellant 2 years later by including nitroglycerin in the mix. Alarmed at the progress on the continent, the British formulated a new brew similar to Nobel's, adding petroleum jelly. The mixture formed a dough that could be forced through dies to product long strings. This new propellant was christened 'cordite'.
I hope you have found this brief summary of the development of gunpowder and its particular relevance to the American Civil War of as much interest as I did in researching it.
Philip Clark, 19th Indiana
The above article first appeared in the ACWS Newsletter, Autumn 2007