Standing Well Back
Technology Development

Inventing Detonators

I’m intrigued by the chain of historical inventions that led to the modern detonator.

Detonators for explosive charges evolved from firearm trigger mechanisms and I see these as an invention continuum, with one leading to another. Alongside these mechanical inventions, chemical discovery runs as a parallel track, particularly the discovery or primary explosives and high explosives, which detonate by shock (gunpowder being a low explosive which explodes by deflagration)

Initially, I guess the first “initiators” were simply burning fuzes which transmitted a flame to gunpowder. However there is some early mention of a some victim operated mechanisms perhaps using friction devices or steel and flint levers.   See Chinese IEDs here.  

To help undertsand the chain of scientific, chemical, physical and mechanical inventions that took us down this path the folloing rough time line might be useful:

Pre 1400 – Burning fuzes of various types, igniting gunpowder by burning.

Early to mid Mid 1400s – Invention of the matchlock mechanism to initiate firearms. Note that this was definitely a European invention – the Portuguese took matchlocks and introduced them to China and Japan.  (The story of how the Japanese obtained and reverse engineered the matchlock will be the subject of a future post) .

About 1500 – Invention of the wheel-lock, possibly by Leonardo Da Vinci, which introduces a new mechanical action to apply a burning fuze to a specific point.

1540 – The snaplock was invented, using a flint initiator. This was a precursor to the more sophisticated flintlock

1558 – The snaphaunce was developed which incorporated a mechanism for keeping the gunpowder covered until the flint fell, when the cover is opened automatically.  The cover is called the frizzen.

1588, a time initiated system used by Giambelli to explode the “Hoop”, with a timing mechanism causing ((I’m guessing with a snaplock or snaphance) to initiate the charge.

1602  Gold fulminate (the first primary/high explosive) discovered by John Tholde of Hesse.

1610 – The first flintlock initiation system developed The flintlock mechanism is an evolution of the snaphaunce whereby the frizzen is not only a cover for the pan of gunpowder, but also the steel face on which the flint strikes to cause sparks.

1659 Robert Hooke and Thomas Willis discover the primary explosive characteristic of Gold hydrazide

1745  Dr Watson of the Royal Society showed that an electrical spark from a Leyden jar could initiate a small blackpowder charge.

1750  Benjamin Franklin initiates gunpowder with an electrical spark and makes small paper tubes of  powder with two wires inserted and a spark gap created.

1788  Silver fulminate was first made by French chemist Berthollet.

1776 – American revolutionaries used adapted firearm mechanism to make contact mines consisting of “kegs” of gunpowder which were floated down rivers.  The kegs have fastened to the lid a wooden arm which when it touched a target ship connected to an iron pin, engaging a flintlock device from an adapted firearm, causing the main charge to explode.  Note the similarities in principle to much later IED initiators here.  I’ll post some images of these “kegs’ in future posts.

1777 – Italian scientist Alesandro Volta, describes how he had fired pistols, muskets and a ”mine subacquee” (underwater mine) electrically – it appears he used a hot wire to initiate a glass bulb full of a flammable gas.

1782 – Another Italian scientist, Cavallo, described detonation of a charge of gunpowder, electrically, using an incandescent wire embedded in the powder

1795 – Cavallo uses another method, using gunpowder mixed with steel filings, with two electrical probes embedded in it.

1799 – Fulminate of mercury, a primary explosive later used in detonators was first prepared by Charles Howard. Interesting reports on his experiments are here and I think its very significant indeed that Howard actually tested electrical initiation of mercury fulminate. I note also that Howard refers to French scientists electrically initiating some form of potassium chloride based explosive in the late 1700s.  Howard’s description of the experiments he conducted with mercury fulminate are fascinating – clearly he hoped he had invented an alternative to gunpowder, but initiating mercury fulminate within a gun caused some catastrophic damage to his equipment!  There is a great description of how Howard measured the volume of gas produced from a specific quantity of the explosive.

1812 – The Russian military scientist Pavel Schilling developed an electrically initiated IED, as a mine.  My apologies, in earlier posts I credited this to others later in the 19th Century, and I have only recently discovered Schilling’s  (and Volta’s, and Howard’s) technologies.  Schilling gradually improved the associated technologies, insulating wire with tarred hemp and copper tubing, and devising a carbon arc initiator.

Also in 1812 – Prussian scientist Sommerring improved the insulation of electrical wire, using rubber and varnish, allowing further capabilities to be developed in initiating explosives.

1820 – American scientist Robert Hare, worked on electrical initiation of flammable gases. Hare also developed a “plunger” type galvanic machine for producing electrical charges for this purpose.

1822 – Hare used  a hotwire embedded in a pyrotechnic mixture to initiate a blackpowder charge.  In the 1830s Hare also produced a tin tube container packed with powder and with an ignition wire for rock blasting but foresaw the military importance of command initiated explosive charges.

1829 – A young Samuel Colt initiated an under water charge electrically perhaps using a tarred copper wire.

1831 – The Bickford burning fuze was invented, taking away the guess work about time delays for burning fuses.

1837  Colonel (later General) Pasley of the Royal Engineers developed chemical then an electrical initiation mechanism to explode gunpowder charges under water. Pasley’s work appears to have been prompted by reading a  newspaper report of an “ordnance accident”, in Russia, when Tsar Nicholas I narrowly escaped death when viewing a demonstration of electrically initiated gunpowder charges used to blow up a bridge, presumably developed by Schilling. Pasley read the article and then sought the advice of English scientist Charles Wheatstone to consider how he might use the same concept.  Pasley’s contributions to military engineering are huge, and his explosive related inventions are very significant if only a part of that broader work.  I have yet to find details of Pasley’s chemical fuzes, but his electrical initiation mechanisms used electrically heated platinum wire, with the electricity provided by early galvanic cells. Pasley solved the problem of insulating the wires so they could be used under water, by coating wire with gutta percha. The platinum wire (or foil) provided enough heat to initiate the gunpowder it was embedded in.  However some reports state that the electrical system caused a detonation by a “galvanic spark” so the actual mechanism is still a little unclear.   I’m very intrigued by the chemical fuzes and how they worked, given the nature of the underwater tasks that Pasley developed the explosives for. I think it likely that there would have been some form of command pull to initiate the chemical reaction once the divers were clear and safe.  Chemically the reaction may have been similar to Nobel’s (later? ) designs.

1830s  –  Immanuel Nobel developed chemical initiation mechanisms to initiate gunpowder. The mechanisms used a glass vial containing suplhuric acid, which when broken (usually by an enemy) caused the acid to fall by gravity onto potassium chlorate, which ignited and caused surrounding gunpowder to initiate. These were confusingly called “Jacobi” fuzes after the Russian scientist for whom Nobel worked.  Jacobi led the Russian “armed services committee for underwater experiments” between 1839 and 1856. It is clear that Jacobi’s secrecy prevented international publication of the scientific achievements he made in electrical initiation. Jacobi’s work  from 1839 seems to have been prompted by both Schilling and Pasley.  What is significant is a reference I have found to Jacobi developing “mercury connecting devices” which probably mean some form of mercury electrical switch to initiate contact mines in the 1850s.

1830s, Mercury fulminate was used in copper caps used as firearm initiators taking the place of flint, and making the process of initiating a firearm much less dependent on flint and the weather.

1839 – Other British Royal Engineer salvage operations in Bermuda and in Bengal on the Hoogly river used electrically initiated charges.  I have a great piece of reseacrh to blog about with regard to the Hoogly river operation.

1840s – Samuel Colt conducted extensive work on highly complex electrical initiation systems for sea and river mines.

1848 – Werner von Siemens developed electrically initiated sea mines.

1863 – Alfred Nobel (Immanuel Nobel’s son) published his patent for a practical detonator to initiate nitro-glycerine.  Note that this was four years before his patent for dynamite.  In modern parlance this was a non electric blasting cap, itself initiated with burning fuse.   The detonator consisted of a small blackpowder charge, a wooden plug and a small quantity of nitroglycerine held within a metal cylinder. The black powder is initiated by a burning fuze, which pushes the wooden plug down the cylinder, which then strikes the niroglycerine with kinetic energy.

1865 –  Nobel refined his detonator design significantly, with a small metal tube containing mercury fulminate

1868. H. Julius Smith produces a detonator that uses a spark gap and mercury fulminate.

1875 The electrical detonator using a hot filament was developed independently by Gardiner and Smith

1760-1770

Explosion kills 3000 people, and another 4000

Around about 1751, Benjamin Franklin became the first person to initiate explosives with electricity.  Franklin, as usual, was well ahead of other scientists around the world.  While one aspect of this research leads us to modern electrical initiation of explosives and munitions another leads us towards the hazards of lightning when associated with stored munitions, and Franklin became expert at lightning conductors for munition stores.

For the past few years I’ve been mentally filing interesting accidental explosions from history and I’m now being encouraged to gather my notes together, and indeed relay some of the intriguing aspects to these stories. Shortly you’ll see a new page on this blog dedicated to such events.

Here’s a great example:

In August 1769 lightning struck the tower of the Church of San Nazaro on Brescia, Italy.  In the vaults of the church over 200,000 pounds of explosive was stored. The resulting explosion killed 3000 people and destroyed a large part of the city.

For many centuries gunpowder was stored in churches – there seems to have been a belief that the church bells prevented lightning. Unfortunately I guess the opposite is true – the tall steeples and towers on a church actually encourage lightning strikes.  During thunder storms teams of men rang the bells in church towers in efforts to prevent thunderstorms.  During the period 1753 to 1786 lightning killed 103 French bell ringers. A triumph of belief over evidence surely.

Interestingly Franklin was extremely active in advising European governments after the Brescia event on the principles of lightning protection for munitions stores. At one stage there was a dispute over the best shaped lightning rods , with Franklin a proponent of sharp pointed rods on top of buildings and an Englishman, Benjamin Wilson urging the use of ball shaped terminals below the roof line. The argument became political, and George III decided he didn’t want American advice…. And Franklin’s conductors were replaced on several British munitions stores.  One of them in Sumatra subsequently disappeared with a bang during a  thunderstorm.

As late as 1856 gunpowder stored in a church in Rhodes was hit by lightning and it exploded killing , allegedly, 4000 people.

Command IED

Early history of command wire electrically initiated IEDs

In some of my previous blogs I wrote about the first command wire IEDs occurring in the US Civil War, then had to correct myself as I found earlier examples in the Crimean war and then again earlier incidences by both Immanuel Nobel and Samuel Colt.

Well, I keep finding other perhaps earlier references as I dig into this and follow this “historical alley” and it’s really quite interesting and clearly things go back further in time than I had appreciated.  Here’s some extracts from what I’ve been digging up.

It starts with some further exploration into the efforts of Samuel Colt, the American industrialist and arms inventor. Separate from his efforts developing small arms, Colt for many years attempted to get the US government interested in a system for defending the US coastline which he referred to as his “Submarine Battery” which were essentially water-borne command initiated sea mines.  I attempted to try and find the inspiration for Colt’s efforts and the science on which he based his submarine munition technology.

I have in earlier blogs discussed the parallel work of Immanuel Nobel (father of Alfred Nobel) who developed command initiated sea mines for the Russian Navy at about the same time. It would appear that another 19th century military industrialist, this time the German Werner von Siemens was also developing very similar technologies perhaps a few years later in 1848, compared to Colt and Nobel who worked on their versions in the early part of the same decade. What is unclear is if these three entrepreneurial military technology developers were aware of each other’s developments.  Siemens’s devices were used to protect Kiel from Danish naval attacks in 1848.

But pertinent to the subject of electrical initiation of IEDs is a letter written by Benjamin Franklin in 1751 to Mr Peter Collinson of the Royal Academy in England which states

I have not hear’d, that any of your European Electricians have hitherto been able to fire gunpowder by the Electric Flame. We do it here in this Manner.

A small Cartridge is filled with Dry powder, hard rammed, so as to bruise some of the Grains. Two pointed Wires are then thrust In, one at Each End, the points approaching each other in the Middle of the Cartridge, till within the distance of  half an Inch: Then the Cartridge being placed in the Circle (circuit), when the Four Jars (galvanic cells) are discharged the electric Flame leaping from the point of one Wire to the point of the other, within the Cartridge, among the powder, fires It, and the explosion of the powder is at the same Instant with the crack of the Discharge

I wonder if we can call this the first electrically initiated IED? Albeit manufactured with pure science in mind rather than as a weapon.

Inspired directly by Franklin, the Italian Allessandro Volta wrote to a colleague in 1777 describing how he had fired muskets, pistols and an under-water mine by means of his electrical piles. I suspect this was the first electrically initiated IED actually intended as a weapon.

Volta’s Italian compatriot, working on a telegraph, Tiberius Cavallo then took a step further in 1782 in the following manner

The attempts recently made to convey intelligence from one place to another at a great distance, with the utmost quickness, have induced me to publish the following experiments, which I made some years ago. The object for which those experiments were performed, was to fire gun-powder, or other combustible matter, from a great distance, by means of electricity. At first I made a circuit with a very long brass wire, the two ends of which returned to the same place, whilst the middle of the wire stood at a great distance. In this middle an interruption was made, in which a cartridge of gunpowder mixed with steel filings was placed. Then, by applying a charged Leyden phial to the two extremities of the wire, (viz. by touching one wire with the knob of the phial, whilst the other was connected with the outside coating) the cartridge was fired. In this manner I could fire gunpowder from the distance of three hundred feet and upwards.

I think this may effectively be the first command wire initiated IED.

The next issue to be dealt with was waterproofing electrical cable and a variety of attempts were made using a range of substances including india rubber, varnish and tarred hemp. The Russians appear on the scene. Baron Schilling Von Canstadt was a Russian diplomat in Bavaria who took great interest in scientific developments. On his return to St Petersburg in 1812 and driven by war with France, Schilling Von Canstadt developed electrically initiated charges that could be fired across a river, the cable running through the water, with a carbon arc initiator. These were demonstrated in 1812 but do not appear to have been adopted by the Russian Army. Later after the Russians entered Paris after Napoleon’s defeat he undertook a number of similar experiments crossing the Seine.   Here’s a description of him demonstrating a command wire IED to Tsar Alexander I

Once Baron Schilling had the honor to present a wire to the Emperor in his tent. He begged his Majesty to touch it with another wire, whilst looking through the door of the tent in the direction of a very far distant mine. A cloud of smoke rose from this exploding mine at the moment the Emperor, with his hands, made the contact. This caused great surprise, and provoked expressions of satisfaction and applause.

His successor, Tsar Nicholas I was fortunate to escape serious injury in 1837 when an electrically initiated charge was used on a demonstration to destroy a bridge but the demonstration went wrong and the charge detonated prematurely or with larger effect than expected.

The next on the scene were the British. Colonel Pasley of the Royal Engineers was inspired by a newspaper report of the accident in Russia and working with the electrical scientist Wheatstone developed insulated cables and platinum filament exploding detonators around 1839.

Also in the 1830s, American scientist Robert Hare developed “galvanic techniques” for quarry blasting.

Enough for now – some time in the future I’ll return to Colt’s submarine battery, but will state here that as a 15 year old boy in 1829 it appears he had his first success in initiating an explosive charge under water.

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