Monday, February 13, 2017

Smokeless Powders: Cordite

In our last post, we studied the invention of ballistite by Alfred Nobel in France. In today's post, we will study how Britain managed to obtain a similar smokeless powder: cordite.

As we saw previously, the French had managed to invent a smokeless powder for military use in 1884, which they called Poudre B and had developed a new rifle, the Lebel M1886 rifle in 1886, after which other governments became aware that the French had a new secret propellant that was superior to black powder. Shortly after this, Alfred Nobel invented ballistite in 1887 and tried to sell it to the French military. However, since they had already settled on using Poudre B and partly because of Poudre B's inventor, Paul Vieille, having connections with the French military, the French turned Alfred Nobel's offer down, even though ballistite was superior to Poudre B. Therefore, Nobel tried to sell his invention to other countries and managed to make a sale to the Italians. While the French weren't about to reveal the secrets of Poudre B to others, Nobel was selling ballistite to anyone who could pay him. In 1888, the British government formed a special commission to gather information about Vieille's and Nobel's discoveries. The British feared that if a smokeless powder was actually invented, they needed to get access to the technology as soon as possible, in order to remain a world power. The British commission's mandate was "to investigate new discoveries, especially such as affected the use of military explosives, and to submit to the War Office, proposals for the introduction of any technical improvements in the field."

One of the two scientists that the British put in the commission was Sir Frederick Abel, who we studied about in previous posts. Abel was instrumental in improving the Von Lenk process of manufacturing gun cotton and making it safer. The other scientist was Sir James Dewar, who was also a well known chemist and physicist of that era.

Sir Frederick Abel
Click on the image to enlarge. Public domain image.

Sir James Dewar
Click on the image to enlarge. Public domain image.

Nobel was pretty well acquainted with both men. Abel was actually a sort of rival to Alfred Nobel about 20 years previously, when Nobel had tried to set up a factory to manufacture dynamite in Britain and Abel had managed to convince British authorities that gun cotton produced by his process was safer to make and thereby prevented dynamite from being sold or manufactured in Britain for a long time. However, as time passed, the two rivals had become somewhat friendly to each other, even exchanging letters and occasionally meeting each other in Paris or London to discuss technical matters. James Dewar was a close friend of Abel and he too had corresponded with Nobel before on technical matters in chemistry.

As part of the commission's study, they requested some detailed information about production and samples of ballistite, which Nobel readily supplied to them. They also carefully studied Nobel's patent claim for ballistite in France. This is where Nobel's patent claim came back to haunt him. His patent for ballistite stated that "ballistite was a combination of equal parts of nitroglycerin and nitrocellulose "of the well known soluble kind", with about 10% camphor. " The wording here is very precise and your humble editor has taken the liberty of highlighting a few bits, because they are important to the next few paragraphs.

So in 1890, Nobel's Explosives Company in Scotland obtained a British patent for ballistite and tried to market it to the British War Office, only to be informed that they had already acquired a patent for a smokeless powder invented by Abel and Dewar, called "the committee's modification of ballistite", or cordite. While looking at Nobel's patent notes on ballistite, the two chemists noted that they could make a few small changes to the original formula and get similar results with the modified formula. Therefore, they quickly took out a patent in secret for their new substance and told the British military about it first, before informing Nobel about it.

Cordite had a few minor modifications to the original ballistite formula. It used vaseline instead of camphor, which was a better stabilizer anyway. Secondly, it used a larger proportion of nitroglycerin in its formula. Thirdly, the formula for ballistite had specified nitrocellulose "of the well known soluble kind" (i.e. a collodion paste that was soluble in water). The formula for cordite used the insoluble form of nitrocellulose (i.e.) gun cotton instead.

Of course Nobel was extremely angry about this and launched a patent infringement lawsuit immediately. The case dragged on to the Chancery Division Court in 1892, which ruled against him. Nobel appealed again and the case got pushed up into higher courts until it reached the House of Lords in 1895, which also ruled against Nobel, due to technicalities in his original patent application, and he was ordered to pay court costs. The problem was that his patent clearly specified that it used "the well known soluble kind of nitrocellulose", whereas cordite used the insoluble kind. The Lord Justice Kay was actually quite sympathetic to Nobel in his remarks: "It is quite obvious that a dwarf who has been allowed to climb up on the back of a giant can see farther than the giant himself ... In this case, I cannot but sympathize with the holder of the original patent. Mr. Nobel made a great invention, which in theory was something extraordinary, a really great innovation -- and then two clever chemists got hold of his specifications for the patent, read them carefully, and after that, with the aid of their own thorough knowledge of chemistry, discovered that they could use practically the same substances with a difference as to one of them, and produce the same results one by one". Therefore, what Abel and Dewar had done was probably morally wrong, they were technically and legally in the right, as cordite was sufficiently different from ballistite to have its own separate patent.

Nobel was naturally not very happy with the court decision, but he did manage to sell ballistite to quite a few other countries. After a few years, ballistite was being used by the militaries of Italy, Germany, Austria-Hungary empire, Sweden and Norway. Poudre B was being used by France, Russia and USA. Cordite became the predominant propellant used by the British empire, many countries in South America and Japan. Nobel's Explosive Company eventually manufactured both ballistite and cordite (even though his lawsuit caused the British government to not award any contracts to his company for over a decade afterwards). The company paid Nobel a half portion of the royalties from every batch of cordite produced, so he did make some money in the end.

In the next couple of posts, we will study the process of making cordite in some detail.

Wednesday, February 8, 2017

Smokeless Powders: Ballistite

In our last post, we talked about developments of smokeless powders in France, leading to the invention of Poudre B smokeless powder. In today's post, we will study about another smokeless powder that was developed in France as well, but it wasn't developed by a Frenchman. Instead, it was developed by an Swedish inventor who happened to be living in Paris at that time. We will study the invention of Ballistite.

Alfred Nobel. 
Click on the image to enlarge. Public domain image.

The Swedish inventor we are talking about is Alfred Nobel, who was a prolific inventor and was well known for inventing dynamite (and later, founding the Nobel prizes). Alfred Nobel's father, Immanuel Nobel, owned an armaments factory and Alfred and two of his brothers, Ludvig and Emil Nobel, were all interested in manufacturing better armaments and explosives. Alfred Nobel devoted a lot of his time to studying how to manufacture explosive substances safely and invented (among other things) a detonator, the blasting cap, dynamite, gelignite etc. These inventions (along with shares in the largest oil refinery in Russia, which was founded by his brothers, Ludvig and Robert) made him a very rich man and in 1873, he bought a large mansion on Avenue Malakoff in Paris and moved there. Despite his riches, he did not forget his interest in chemistry and still continued doing research in his laboratory.

It is not known exactly how he discovered how to make ballistite, but from his notes, it appears that he had been working on and off to make a smokeless powder since about 1879. He experimented over many months with various acids to make many explosive prototypes, which he tested at a blasting range outside Paris and then worked with assistants to perfect the manufacturing process. He didn't keep very many detailed notes mainly because of the need to protect trade secrets from competitors.

In 1887, a few months after Poudre B was accepted by the French government, Alfred Nobel submitted a patent application for his own smokeless powder, which he called "ballistite". According to his patent application, this was a combination of equal parts of nitroglycerin and nitrocellulose "of the well known soluble kind", with about 10% camphor. The exact wording on the patent application would come back to haunt him, as we will see in our next post. The purpose of the camphor was to react with any acidic products formed by the decomposition of the other two explosive substances. The camphor helped stabilize the other two substances from further decomposition and prevented explosions. In his 1887 patent application, Nobel wrote, "Celluloid, as a rule, contains nitrated cotton to approximately two-thirds of its weight, but owing to the camphor content and substance's compact consistency, celluloid's combustion, even if fine-grained, is far too slow to make it suitable as a propellant for projectiles. By substituting nitroglycerin, wholly or in part, for camphor, it is possible to produce a kind of celluloid with sufficient consistency to be formed into grains and which, on being loaded into firearms, burns with a subdued rate of combustion."

Like the Poudre B that we studied in the previous post, ballistite is also a substance that burns with much more force than black powder, but produces very little smoke and residue as well. Like Poudre B, it is also a plastic that can be shaped like dough and cut into precisely shaped and sized grains to fit the needs of everything from the smallest pistol to the biggest cannons.

So when Alfred Nobel triumphantly presented his latest invention to the French military in 1887, he was surprised to be rebuffed. It turns out that the French had just settled on using Poudre B a few months earlier in 1886 and Paul Vieille's political connections ensured that Poudre B would be used by the French military even though ballistite was a superior product. Nobel angrily wrote that "for all governments, a weak powder with strong influence is obviously better than a strong powder without this essential complement." Nevertheless, he went about marketing his invention to other countries and on August 1st, 1889, he obtained a contract from the Italian government and opened a new factory in Turin where he manufactured about 300 tons for the Italians. The next year, he licensed his patent to the Italian government for a large sum of money, so that they could manufacture it by themselves. The Italian army, in turn, replaced their old black powder rifles and adopted a new M1890 Vetterli rifle which used ballistite cartridges.

During that period of time, France and Italy were competing with each other, to become great powers in Europe. Naturally, the news that a person living in Paris and helping their enemy with manufacturing superior cartridges did not sit very well with the French public and military. The French newspapers launched a series of articles attacking Nobel's character, accusing him of treason (despite him offering ballistite to the French first and living in France for 17 years) and claiming that he had spied on Vieille and stolen his recipe for ballistite from the laboratories of the French Administration des Poudres et Salpetres. The police conducted a search on his laboratory and shut it down, his testing range permit was revoked and he was prohibited from manufacturing ballistite in France. Therefore, in 1891, Nobel packed up his possessions from his mansion in Paris, along with any laboratory equipment that hadn't been seized, and moved everything to San Remo in Italy, where he bought a large house that he named Villa Nobel. He also built a laboratory close to his new house and continued experimenting there for the rest of his life.

It must be noted that the production process of ballistite involved making flexible sheets, which were cut into flakes in cutting machines, or in pastry cutters, or squirted through gratings to form threads. It was a curious fact that many machines that were originally used in Italy to make bread, pastries, pasta, spaghetti and macaroni, were now employed in the manufacture of smokeless powders!

Italy wasn't the only country that Alfred Nobel was marketing his invention to. In the next post, we will study how he accidentally helped Britain to make their own smokeless powder.

Sunday, February 5, 2017

Smokeless Powders: Further Developments in France

In our last post, we studied some developments in powder technology advancements in France. In today's post we will study some further developments in the field.

In our last post, we studied how the team of Serrau and Vieille had made improvements in the process of measuring chamber pressures. In fact, Vieille invented a modification to the crusher gauge that enabled him to record the explosive strength over time, rather than just the maximum explosive strength. He also studied the effect of other parameters such as grain sizes and shapes and how they affected the speed of the explosion and the pressure curves generated over time. This enabled him to prove that the theory originally suggested in 1839 by General Guillaume Piobert, was indeed valid fact, and that combustion does take place in parallel layers (Piobert's law)

Paul Vieille
Image released under the Creative Commons Attribution-Share Alike 3.0 Unported license.

In the case of classic black powder, the powders are made of a mixture of charcoal, potassium nitrate (saltpeter) and sulfur and made of individual grains. They can be made to varying densities by refining and compressing them, which we studied in several previous posts. However, there are still spaces in between the grains and these interstices cannot be completely got rid of in conventional black powder. Therefore, no black powder really burns according to Piobert's law of parallel layers -- for this to happen, the black powder needs to be a homogeneous mixture without these spaces between the grains.

However, Vieille didn't just study black powder, he also extended his study newer explosives (including gun cotton) as well. Due to his studies, he now understood why gun cotton's fibrous structure caused it to burn much more quickly in a barrel than black powder and why it produced much more force. He understood that if he could somehow reduce the combustion rate of gun cotton, then it could be used as an excellent propellant for firearms as well, and to do this, he would need to change the structure of the gun cotton fibers, so that he could enable it to burn in "parallel layers". His idea was to convert the gun cotton into a "powder", not like black powder which has gaps between the grains, but more like a homogeneous material whose geometry could be modified by the manufacturer to burn at a precise rate in layers. His method was to dissolve the gun cotton in a mixture of alcohol and ether, stabilize it with amyl alcohol and form a colloidal paste. This colloidal paste could then be passed through heavy rollers to make thin sheets of precise thickness, extruded into rods, molded into plates etc. and then dried and cut into flakes of precise shapes suitable for the ballistic requirements of any particular firearm or artillery piece. All this development took place between 1882 and 1884 and the first practical results came out in 1884.

A sample of Poudre B. Click on the image to enlarge.
Image released under the Creative Commons Attribution-Share Alike 3.0 Unported license by snipersnoop

The first version of this new propellant was called "Poudre V". The word "Poudre" means "powder" in French and the letter "V" at the end stood for the name of its inventor, Paul Vieille. However, the French military were concerned that the Germans might find out details about this new invention and therefore, they arbitrarily changed its name to "Poudre B" so that the inventor's name would no longer be in it. Some claim that the name stood for "Poudre Blanche" (i.e. white powder), to distinguish it from black powder (note that Poudre B is not white colored either, it is actually a dark green and gray color), but the real reason for renaming it was to confuse German spies. The French military quickly adopted this powder and they also developed a new rifle for this, the 8 mm. Lebel rifle, in 1886. This was the first military rifle to use smokeless ammunition.

The Lebel rifle was a game-changer on the battlefield. First, it had longer range and a flatter trajectory than other rifles. Since the ammunition produces much less smoke, a soldier could stay hidden from the enemy, but locate them by observing the smoke from their black powder rifles. As the new propellant was three times more powerful than black powder, the cartridges weighed less for the same performance, which meant the soldier could carry more of them. The Lebel could also fire at the faster rate of 43 rounds a minute, compared to 26 rounds for the black powder M84 rifle of the German army. This is one reason why Otto von Bismarck opposed invading France in the winter of 1888 when his war minister Alfred von Waldersee wanted to go to war.

Other foreign powers learned that the French possessed a new propellant by 1886 after the Lebel rifle was accepted into military service. German spies were able to obtain a sample, but could not identify its components or manufacturing process. In 1890, the British managed to obtain some small tablets of Poudre B and picric acid and identified the compounds that form the basis of it. Quickly, the knowledge of its composition spread to other countries as well and they began to manufacture their own smokeless powders as well.

It must be mentioned that Poudre B still had some stability issues, especially when stored for long periods of time, due to the improper removal of acid during their manufacturing process. This caused two French warships, the Iena and the Liberte, to blow up in 1907 and 1911. Meanwhile, the process of manufacturing Poudre B had made improvements and newer versions (such as Poudre BF and Poudre BN3F) were invented by the early 1900s, which were much safer than Poudre B. In fact, the French used a variant called "Poudre BPF1" until the 1960s or so.