Alexander John Forsyth and the invention of percussion ignition

Alexander John Forsysth
Presbyterian minister and inventor Alexander John Forsysth.

The north of the British Isles is a rough country. Wet or cold, often both at the same time. And always windy. The natives tell that there are also good times. But why then do they distillate uisge beatha (the “water if life”), eat sheep's pluck and cut peat? Besides, the Scots are religious and their priests are quite inventive. Alexander John Forsyth proved that these abilities do not only refer to the dear God. Born on December 28, 1769, in Belhelvie, Aberdeenshire, the son of a Presbyterian minister, he studied at Kings College in Old Aberdeen and took his late father's place in 1791. Since the church in the islands was (and is) dependent on donations, hunting for the Sunday roast was sometimes necessary – and that led back to the weather.

Why was Forsyth looking for a new gun powder and a new gun lock?

Forsyth was annoyed at his rifle's flintlock fowling piece, which was common at the time. Not only did he have to keep the powder dry, but he also had to keep the wind from blowing it off the priming pan. To do that, he had to wrap it around. By the time he had unpacked this batch, many a future roast had disappeared. And then there were the grouse! Forsyth found that the clever fowl took cover as soon as the priming powder flashed in the pan. Now, as vicar of his small Scottish country parish, he had plenty of free time – and good manual skills. He set up a shed in the garden, soon known as "Forsyth's smithy”. There he tinkered with both mechanical and chemical stuff. His first goal was to develop a detonating powder that was insensitive to moisture, and, since he was already at it, a gun lock that was resistant to weather – goal two.
Fulminate of mercury as a primary explosive was already known, but it had disadvantages because it was very sensitive to impact and shock. Experiments with the mercury fulminate work under laboratory conditions, but in practice it decays easily and is highly toxic. So it was a matter of adding something to stabilize it. Forsyth tried charcoal and graphite. He finally mixed a detonating powder that could be transported without problems and ignited perfectly even in damp conditions: problem one was solved. The flintlock remained. He wanted to keep its hammer. After all, it reliably indicated whether the gun was cocked. The firing pan was the troublemaker – but how else to get the ignition flame into the barrel?

Forsyth's first version: the scent bottle

the falling hammer strikes the firing pin.
How it works: the falling hammer strikes the firing pin. This ignites the priming mixture inside the "bottle". From there, the ignition flame goes to the propellant powder.

Forsyth extended the priming hole to the outside. He attached a hollow screw-threaded plug and, pivoting on it, a container that held his primer. Because the box looked like a smelling bottle, experts call the distinctive lock fitted in this way a "scent bottle lock". A spring-loaded rod (the firing pin) sat at the top of the bottle. The blow of the hammer pushed this down onto the priming composition. On average, and depending on the consistency, the amount in the container was enough for five to six ignitions. It was filled through a hole (later sealed by means of cork or ivory plates). This part is also intended as a relief in case the priming composition should ever ignite completely. At the top, a nut that can be loosened with a fork screwdriver closes the container. The horizontal screw-threaded plug was set into the side of the barrel and had two micro-touch holes at right angles to each other. The vertical hole was slightly larger at the top to form a round chamber (pan). In this chamber, the actual ignition was by percussion. Therefore, this chamber was often lined with platinum to protect against corrosion, as collectors know from the vents of high-quality flintlock and percussion firearms. From the chamber, the priming flame gets through the small vertical touch-hole, then passes at right angles through the plug onto the powder charge in the barrel.

A hollow threaded plug extends horizontally from the bottle with the primer and firing pin
A hollow threaded plug extends horizontally from the bottle with the primer and firing pin: it connects the priming element to the barrel and directs the ignition flame into it.

The gun was loaded as usual from the muzzle. Now the shooter turned the bottle by about 180 degrees – corresponding cut-outs precisely limited its path. When the firing pin was at the bottom, some priming powder trickled out of the container into the ignition chamber until it was full. Now turning the bottle back, the firing pin was up, the gun was ready. It could be transported safely in this way. You had to cock the hammer to fire. When shooting, it hit the firing pin, which ignited the priming charge. This resulted in minor traces of gunshot residue on the outside of the firing pin. Because of the high precision of the part, these had to be wiped off immediately to prevent jamming. For this purpose, there was a rectangular recess in the bottle on the rotating surface. In it sat a greased piece of leather or cork. This was used to lubricate the plug regularly. This type of lock was constantly improved. Initially, the plug was screwed through the lock plate into the barrel. Also, the bottle could only be removed after loosening screws, which made disassembly very difficult. Later, the plug was screwed directly into the barrel, the lock plate had a corresponding recess and the bottle could also be removed easily via a spring catch. And instead of one, there were later two recesses for lubricating.

Forsyth's second version: the sliding lock

This version is called sliding because the priming mixture container can run back and forth on a rail on the lock. When the hammer is cocked, a connecting rod pulls the container back. Ignition powder trickles into a round hole that serves as the ignition chamber. The hammer strikes off and ignites the priming charge. It has a special shape for this purpose. The actual firing pin is screwed into the hammer. It, too, is an expandable part. While the hammer is striking off, it pushes the priming powder container out of the danger zone via the rod.

On His Majesty's service

Behind the hammer is a typical English slide safety.
Behind the hammer is a typical English slide safety. In front of the bottle, a stop limits the rotational movement.

Forsyth had influential relatives with good connections to the government. In February 1806 they brought the matter to the attention of Francis Rawdon-Hastings, the Earl of Moira – the master-general of the Ordnance, the man responsible for British war material. The nobleman asked Forsyth to make further improvements in the Tower so that it could be used for war purposes. This began immediately in strict secrecy. Forsyth received an initial payment of 100 pounds. Further development took longer than anticipated, and the clergyman had to ask for leave from his church and provide a substitute. These expenses were met by the War Office. As a fee, Forsyth agreed on the equivalent of the gunpowder saved in two years by introducing his lock to the army. Lord Moira forbade him to patent his invention while working at the Tower. Moira received the first manufactured double-barreled gun for private use. At the same time, work began on a firing lock for cannons. For reasons of secrecy, Forsyth moved his workplace to a rented workshop outside the Tower. There he worked with his assistant Joseph Vicars.

At the bottom of the bottle there is a filling and unloading port. 
At the bottom of the bottle there is a filling and unloading port. It is closed by an ivory plate: another detail of this noble pistol. Note the fine engravings and the excellent fits.

In April 1807, a new master-general of the Ordnance arrived. He quickly had the work stopped. It's possible that he didn't see the benefits of Forsyth's work, but he did see the problems it posed. If the scent bottle system was to function reliably, the parts had to be manufactured with the utmost precision, including thread fits that had to be ground by hand. And replacing burned-out small parts such as the firing pin and spring was not something that the rough motor hand skills of untrained soldiers could have managed in the field. The matter had cost the government just under 604 pounds, or about 119,000 euros in today's value. Since the lock was not adopted, Forsyth saw no money. So he went other ways.

Alexander John Forsyth – The entrepreneur

In 1807, Forsyth was granted patent No. 3032, the drawing for which was made by a friend named James Watt – right, the one of the steam engine. The drawing states the composition of Forsyth's ignition powder: 3 parts potassium chlorate, 0.5 part sulfur and 0.5 part charcoal. To market his invention, he and his financially strong cousin James Brougham formed the Forsyth Patent Gun Company in June 1808. Here, Forsyth and his employees – among them James Purdey, who later became famous for his shotguns – installed the new locks. At first, lock type one, i.e. the scent bottle, could be found on all long guns, but only rarely on pistols. From about 1813 to about 1828, the beginning of the percussion cap era, Forsyth used his second type of lock – in which the hammer was coupled with the ignition element – especially for pistols. 4500 locks of all types were made, each lock numbered. Probably not quite that many complete guns were made, because Forsyth also supplied the locks to convert old firearms. The company had an excellent reputation from the beginning and belonged to the crème de la crème of London gunsmiths. Their guns were expensive, but also excellent. And so the company existed until September 29, 1852, the end of which Forsyth did not live to see. On June 11, 1843, he died at the age of 73 while eating a breakfast ice cream. At about the time of his death, the government granted him financial recognition of 1000 pounds for his tinkering. Money that was distributed posthumously among his relatives. They arranged for Forsyth's burial in Belhelvie Cemetery, near his manse home – the grave still exists, but the Forsyth forge in the garden has disappeared. At least, bronze plaques in the Tower of London and the University of Aberdeen commemorate the inventive man of God.


But even such honors do not hide the fact that Forsyth's path led to a dead end. His two systems were too elaborate and too delicate. And already at about the time of his experiments in the Tower, Jean Samuel Pauli in Paris invented the centerfire breech-loading gun. But Forsyth's work laid the groundwork elsewhere: between 1814 and 1822, men like gunsmiths Joseph Manton, William Smith, and landscape painter Joshua Shaw began to fit locks with cylindrical nipples ("pistons") and to develop metal caps for them that could be ignited by a tap. And these primers were initially equipped with the priming compound that Forsyth had developed.

Notes on the purchase of Forsyth firearms

A Forsyth pistol
A Forsyth pistol with bottle scent lock. Browned damascus steel barrel, color case hardened, engraved, walnut stock with hand-cut checkering: all showing stunning workmanship and preservation.

Because of their technical importance, Forsyth's firearms are sought after and expensive. In the May auction at Hermann Historica, for example, a perfect and rare pistol with a scent bottle lock fetched 12,000 euros, while a loose lock 2800 euros, both plus a premium. A British collector removed some of the then already 180-year-old priming powder from the box, filled the container and fired several times. The gun worked perfectly. As punishment, he was allowed to clean, because the mixture is not non-corrosive. Around 1900, the British realized that American collectors were spending a lot of money on what was regarded in the United Kingdom as nothing more than "old junk”. Soon, new Forsyth rifles were made with the help of real locks, and the locks were also copied. However, neither of them was of the same outstanding quality as the originals. Therefore, watch out: Forsyth stamped all locks with "Forsyth & Co Patent" on the lock plate. On the scent bottle variants, "Patent" is additionally written in a crescent shape at the bottom of the powder container, with an "F" above it. The plug screwed into the barrel must also be checked. The original is always slightly conical towards the barrel. With the sliding lock, it also says "Forsyth & Co. Patent" on the lock plate, but only rarely "Forsyth Patent" on the powder container. Rule of thumb for collectors: if the lock appears to be imprecisely manufactured, forget about it.

Text: Stephan Rudloff and Matthias S. Recktenwald


Perhaps there will be another Forsyth gun in Hermann Historica's next May auction. The auction will be held from May 26 to June 2, 2021. The "Firearms from five centuries" auction on May 28, 2021 should certainly be of particular interest to you.

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