You can contact me at rogercdavies(atsquiggle)  If you have a comment and the system won't let you post it, ping me using the @ for (atsquiggle)

This blog has evolved into a review of historical and modern explosive devices, and responses to them. Links are drawn between historical activity and similar activity in the world today. Mostly I focus on what are now called IEDs but I have a loose personal definition of that and wilingly stray into discussions of more traditional munitions, the science and technology behind them, tactical employment and EOD responses. Sometimes it's just about interesting people in one form or another. Comment is welcome and encouraged but I do monitor it and reserve the right to delete inappropriate stuff. Guest posts are always welcome. Avoid any stuff that makes the enemy's job easier for them.

A note on moral perspectives. Throughout this blog there are descriptions of all sorts of people using IEDs, explosives, or suffering the consequences. Some of the people using IEDs are thought of as heroes by some and terrorists by others. One person's good guy fighting for a cause is another person's evil demon.  It's complicated, and history adds another series of filters too. All of us too live in a narrative made up around however we were brought up, what we were taught and what we learned along the way, rightly or wrongly. So if you sense moral ambivalence, one way or the other, well, I'm guilty and I'm not perfect.  By and large though, I have unapologetic sympathy for those dealing with the devices, whether they be soldiers, cops, or whatever, even those who are part of Nazi or other nasty regimes. That's the cool thing about EOD techs - we don't really care who the enemy is.


Entries in 1830-1840 (5)


Augmented reality and explosive initiation - an historical mystery

There is much focus today on "augmented reality” technology and a fair proportion of this is in the defence world. Systems like the Google Glass project and a number of others can be used or adapted to add visible data and tactical information and analysis to a soldier, overlaying that data on what he is seeing. Very hi-tec. So I was surprised when during some research I came across the details of a genuine Augmented Reality technology being used for a defence fire control system in the 1860s over a 150 years ago.

During the 1860's a room-sized camera obscura was used to conduct military research in Belgium. The system was set up to project a "live view" of the River Scheldt in which an electrically initiated underwater mine had been placed. That view was projected onto a large table. The operator of the camera obscura marked the position of the submerged mine on the viewing table, in effect as a data overlay with the image. An enemy ship passing over the mine could therefore be seen and as it approached and when in the optimal position, the mine could be exploded by remote control. The experiment was repeated in Venice in 1866 by Austrian engineers who then held the city, with more elaborate steps to pinpoint the location of the mine, and in this case a series of mines.  As a small boat laid each mine, the operator recorded that position and marked it on the image table.  The boat then did a full circle, I’m guessing 20ft around each mine position, and the operator recorded that circle on the viewing table, in effect becoming a specific kill zone, for each individualy activated mine, presumably numbered,  overlaid on the live image.  This ingenious arrangement was never tested in action.
Doing some more digging on this subject I have found oblique references to the connection with Samuel Colt the American inventor. Colt did indeed develop systems for initiating observed river mines in the 1830s, and this poor diagram, dated 1836 labeled "Submarine Batary first thorts 1836”, drawn by Colt, seems to indicate a reflecting lens which might project an image onto some form of viewing screen. To me that looks like a version of a camera obscura.
This second diragam, an overhead diagram, might be interpreted as a viewing position with a lens in the building at the very top, which projected a view of the scene over a set of terminals for initiation.
This third diagram, again by Colt begins to make sense, perhaps. Note the large lens in the upper right, I think reflecting the camera obscura image onto the actual reflective control panel.  Thus the image is projected onto the swiches. I think….
Colt was incredibly secretive about his inventions, but I think there is a very good possibility Colt had invented something similar to (and possibly more sophisticated than) the 1866 Austrian camera obscura system, but 30 years earlier, or at least had the concept in his head. Due to Colt’s obsessive secrecy I can't be quite sure.  It is possible that as well as protecting the commercial rights to the system with this secrecy, Colt was also very aware that the observation towers housing the “camera” had to be placed on prominent, well visible, high ground - making them potential targets for the dastardly British fleets which his systems were designed to combat. There were plenty of good reasons to keep the observation system secret.  So it is intruiging to wonder how a system, somewhat similar ended up on the River Schelde some years later.
It would be interesting to replicate Colt’s augmented reality fire control system of 1836, wouldn't it? 



Parisian Infernal Machines from about the time of Les Miserables

I’ve posted articles before about IED attacks on Napoleon Bonaparte in 1800 and on Emperor Napoleon III, in 1858, both attacks on their carriages as they went to the opera, along predictable routes in Paris.  

There was however another famous “terrorist” attack between these dates on the French King Louis-Philippe, on 28 July 1835, but on his way to a parade in Paris, and not with an IED - here's the story and the device used to attack him.

The attack occurred on the Boulevard de Temple in Paris. It was mounted by a Corsican terrorist/criminal/rebel, Giuseppe Mario Fieschi.  The device that he built with two accomplices from the Société des Droits de l'Homme is interesting. Reports at the time called the device a “machine infernale” which is the phrase often used to describe IEDs of the time. But this was no IED.  An image of the actual device, now in a french museum is shown below.  It consists of 25 gun barrels mounted on a wooden frame with the 25 barrels pointing slightly downward . The “machine’ was placed at the open window overlooking the route to be taken by the King and fellow dignitaries as they went to inspect a parade of troops.

The barrels were over charged with powder and it is thought up to three musket balls per barrel. As a result there were a number of cases of the breech exploding during the attack - I think you can see this on barrels 2, 14 and 20, numbered from the left.  One of these caused injury to Fieschi as he initiated the device.  I’m not sure of the exact initiation technique, probably Fieschi using a naked flame and swiping across the fire holes at the rear of each barrel. The injured Fieshci was arrested as he fled the scene, his wounds tended, and then after his trial his wounded head was removed from his body by the infamous guillotine.

In terms of target effect, the King was not killed but only slightly wounded. However the 75 musket balls caused carnage and 18 people were killed including Marshall Mortier.  Reports of the time make much of the dastardly deed and the ingenious machine (note that there were seven other plots against the king discovered that year alone - however it was not perhaps such an innovative attack as it might first appear. There are many references to multi barrel firearms going back to the 14th Century.  Around 1500 Leonardo da Vinci had designed similar systems for use in battle, and they were used on a number of occasions in the 17th century. They are referred to as an “orgue” - or organ, given the similarity to the multi-barrel and an organ. 

Leonardo Da Vinci's designs for multi barrel weapons


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


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.


Electrically Initiated Command Wire Devices – the first?

In an earlier post I suggested that the first electrical command wire initiated device appeared in the American Civil War. This was incorrect, as I believe the truth is that such things were first developed by the Russians in the 1830s as electrically initiated sea mines  and later used in the Crimean war by the Russians  .  A “forgotten theatre” of that war was a series of naval engagement in the Baltic as the British and its allies blockaded Russian ports. The Russians protected their ports with ingenious improvised sea mines and a number of these were electrically initiated.

These first "galvanic" initiated mines were developed by Engineer-General Karl Shilder, who was a senior engineer in the Russian Navy – and he had a chance encounter with Alfred Nobel’s father, Immanuel Nobel in the late 1830s.  Immanuel Nobel had developed the concept of a rubber backpack containing explosives for use by the military as a contact initiated explosive mine. He failed to gain interest from the Swedish military so took his ideas to the Russians.  Shilder was on a committee set up by the Tsar to investigate electrically initiated mines. Nobel suggested his contact mine as an alternative and subsequently the idea was presented and demonstrated to the Tsar who rewarded Nobel with 3000 Roubles.  Nobel set up a facility to develop the concepts further and succeeded in a trial in 1842 to blow up and sink a three-masted ship – gaining a further substantial financial prize from the Russian government.

When the Crimean war began Nobel’s mines and other command-initiated devices were used extensively on land and sea, and in particular to protect the Russian naval port of Kronsdtadt on an island in the approaches to St Petersburg.  A British operation to recover and exploit this new foreign technology was mounted and Russian mines was recovered and carefully tested.   Other British attempts to exploit the Russian technology were less successful – a number of senior British naval officers, including the commander, Admiral Dundas were badly wounded when examining recovered Russian devices.  Here’s a diagram of a Russian contact mine, a description of some early naval EOD actions, technical device exploitation and a fascinating account of the stupidity of senior officers, twice in one day – all in one:

They are made cone-shaped of strong zinc, about two feet deep, and fifteen inches wide at top. The bottom holds the powder, about eight pounds; the top is full of air, to keep it up; a strong tube (B B B) goes through the top, and reaches the powder; a small tube about the size of a lead pencil is hung in the centre of the large one (D D) - it pivots on its centre; and fixed in the bottom of the large tube, in the little chamber of priming-powder (C), is a small glass tube (+), sticking up into the bottom of the small tube. You will see that if anything pushes the upper end of the small tube on one side, as I have tried to show in figure 2, as it is pivoted in the centre, it must break off the glass tube, which is filled with some ignitible stuff, which fires the priming-powder (C), and of course explodes the machine. Now the two thin tubes of iron on the top (A A) slide to and fro, out are kept away from the tubes by slight springs. On being touched by a ship's side, or even pressed with a finger, they shove the small tube aside, as in figure 2, and explode the machine. How any were hauled into boats without exploding seems marvellous; but some lost their tubes when canted up to be hauled in; others had been put down with caps on the tops, which prevent their going off. These ought to have been removed; but the parties putting them down had been so afraid of them, they had preferred leaving them safe for us to risking removing the caps themselves. I don't know what the Grand Duke will say if he knows this! Admiral Seymour and Hall got one up, and hauled it over the bows of the gig. How the little slides were not touched is wonderful. It was then passed aft; and the master of the fleet joining them, they, thinking it was damaged with wet, got discussing the way to set it off. Stokes touched the slide, shoved the tube a little on one side, but evidently not enough to break the glass tube. They then took it to Admiral Dundas, and again they all played with it; and Admiral Seymour took it to his ship, and on the poop had the officers round it examining it. Hall, being in the act of hoisting a second one, was on the quarter-deck. Some of the officers remarked on the danger of its going off, and Admiral Seymour said, 'Oh no; this is the way it would go off,' and shoved the slide in with his finger, as he had seen Stokes do it. It instantly exploded, knocking down every one round it. As Hall looked round he saw the captain of marines, a son of Sir John Louis, carried down the ladder, with every bit of clothes burnt off him and covered with blood. He then heard, 'The admiral is killed.' The latter was lying insensible, his face covered with blood; but he soon recovered, though very seriously injured in one eye and the head. The poor captain of marines had pieces of the machine in his legs, besides the burns. Pierce, the flag-lieutenant, much hurt, a piece of iron going through the peak of his cap, and knocking it into the mizzen-top, but not touching his head; a young volunteer also. The signalman holding it up at the time not very much hurt, though burnt; and one lieutenant and the chaplain, though next to Admiral Seymour and close to it, only had their hair singed, and were not hurt at all. Two or three men also slightly wounded. It is a wonderful escape, for pieces of it flew down the main hatchway; and we know that the Russians getting one into a boat exploded it, and killed seventeen men. Admiral Seymour is much less hurt than was first supposed, as he is able to sit up to-day; but concussion of the brain is what they fear. He can see a glimmer of light with the eye, so it is hoped he will recover the sight. The marine officer's is the most dangerous case, but it is hoped he is doing well also.

The extraordinary thing is that the same evening Admiral Dundas and Pelham were examining a tube; so Caldwell went and got an empty machine (that had been cut open) to put the the tube in, to examine how it explodes. While they were close round. it, the admiral shoved the slide, and the tube exploded, shooting up in the middle of them, and hurting the admiral's eyes so much that they were looking inflamed and bloodshot yesterday morning when he was explaining all this to me. 

Moral of the story - don't let senior officers fiddle with recovered devices.  In future blog posts - How the US Army studied the Russian experience of contact and command wire initiated devices and did or didn't employ them in the American Civil War - and the strange story of another US-Russia connection regarding command wire IEDs.