back to article Mirror mirror on sea wall, spot those airships, make Kaiser bawl

Mention the development of air raid early warning systems in the UK and thoughts will most likely jump to the Chain Home radar network of the 1930s. But a system was put in place twenty years earlier to give advance warning of raids by German Zeppelins. These were giant, cigar-shaped, hydrogen-filled airships that unleashed …

  1. Spiracle


    These were giant, cigar-shaped, helium-filled airships that unleashed the first aerial bombing campaign to hit Britain and the civilian population.

    Wasn't it all hydrogen until the US frees up their supply in the 30's?

    As an aside my grandmother (b. 1914) used to tell me that her first memory was of a Zeppelin caught in searchlights over Margate.

    1. Allan George Dyer

      Re: Helium?

      My father (b. 1915) had a similar memory of a Zeppelin over Portsmouth.

      1. Anonymous Coward
        Anonymous Coward

        Re: Helium?

        One of my grandfathers, born 1905, was taken to see the Zeppelin that came down at Cuffley in 1916. He recalled bodies of the crew still scattered on the ground and the large crowd of sightseers taking souvenirs from the wreckage.

        I just Googled, and it was apparently the first Zeppelin to be shot down. Apparently there's a memorial to the pilot who shot it down - I'll have to see if I can find it.

        1. Anonymous Coward
          Anonymous Coward

          Re: Helium?

          He's buried at West Brompton Cemetery and a memorial in his home town.

    2. Anonymous Coward
      Anonymous Coward

      Re: Helium?

      My grandmother saw the Cuffley Zeppelin come down. One thing to note is how few of them were totally destroyed by hydrogen fires. Hydrogen rises, Zeppelin falls.

    3. Anonymous Coward
      Anonymous Coward

      Re: Helium?

      It’s a mistake in the article. Every German airship was inflated with hydrogen, although Hindenburg was originally designed to fly with helium.

  2. Ebbe Kristensen

    Not helium

    Germany did not have the capability to produce helium in the amounts required for airshps so they used hydrogen instead. See also the wikipedia article on Zeppelin airships

  3. Aladdin Sane

    Now I want to watch Zeppelin.

  4. Anonymous Coward
    Anonymous Coward

    Looks like it was a sound idea. I do enjoy these articles.

    1. Adam 1

      I hear what you did there

    2. james swiers

      a sound idea indeed

  5. John Sager


    Do you really need precision to 4 significant figures on your unit conversions - e.g 5.8m (19.02 ft)? Why not just 19 ft? Similarly for driving distances. 2, or possibly 2.5 sig figs (to the nearest 0.5) is perfectly adequate and it reads better. You need lots of precision on the GPS coords, as you have, but that's the only place it's important in this article.

    1. Gene Cash Silver badge

      Re: Precision

      Actually, I was hoping for a banana in the picture for scale... or failing that, Dabbsy.

      1. Alistair Dabbs

        Re: Precision

        I'll meet you half way and lend you a banana.

        1. Ragarath

          Re: Precision

          Because this is El Reg and we would harass them if they got the conversion wrong, which he did anyway as it is 19.03 to 2 significant figures.

          1. Anonymous Coward
            Anonymous Coward

            Re: Precision - which he did anyway as it is 19.03 to 2 significant figures.

            While we're down this rabbit hole let me point out that 19.03 has four significant figures, not two.

            1. Ragarath

              Re: Precision - which he did anyway as it is 19.03 to 2 significant figures.

              Gosh darnit you got me. I meant to change it to two decimal places but missed the edit timer. Have a thumbs up.

    2. Adam 1

      Re: Precision

      I have a bigger problem than the rounding. Metres? Feet? I mean, what is wrong with saying about 41 linguini?

  6. GlenP Silver badge


    I was in Fulwell a couple of weeks ago and would have gone to see the site there if I'd known.

    Our family are well aware of the Zeppelin raids and in particular the one on Sunderland on 1st April 1916. My grandmother was born prematurely the next day and according to the doctor wouldn't have survived to full term.

  7. Dodgy Geezer Silver badge

    It was....

    ..the 'can do' attitude of those days that always impressed me.

    Individuals had an idea, built their own prototypes, went to a government office and pushed for official acceptance, and then put the whole thing together, in a very short time-frame. Look at the kid's adventure books and comics of the period - they will often have stories of absent-minded inventors of evil geniuses inventing amazing machines with staggering powers. On their own....

    Nowadays, for everyone with a new idea, there are 50 or more by-law drafters. Health and Safety officers, chemical storage and usage regulators, diversity directives, health initiatives, energy saving administrators, town planning, zoning and development co-ordinators, EU guidances, regimented codes of practice for handling and labelling everything, governance and compliance executives, accountants and tax inspectors, environmental legislators with a host of activists to support them, work hours directives, employment contract and pension codifications, child protection policies, data protection registers.....

    1. Anonymous Coward
      Anonymous Coward

      Re: It was....

      You left out "big corporations waiting to steal your ideas"

    2. Herring`

      Re: It was....

      There is something about the corporate/large organisation environment that kills creativity and innovation. Probably because actual innovation looks a lot like "dicking about with something that might never work". In fact, that's exactly what innovation is.

    3. Prst. V.Jeltz Silver badge

      Re: It was....

      "Individuals had an idea, built their own prototypes, went to a government office and pushed for official acceptance" and "dicking about with something that might never work"

      Thats a big part of that film* about the birth of radar with Eddie Izzard (Article tie-in!)

      Imagine dicking about with something that might never work , during a war where lives are lost everyday that could have been saved , had you got your idea working yet ....

      Thats pressure!

      *and , no doubt , reality.

      1. Dodgy Geezer Silver badge

        Re: It was....

        Barnes Wallace had the theory for the bouncing bomb sorted, but needed official agreement to actually create one (together with all the support systems like the storage and handling tools, the dropping system and the aiming system). He was given 3 months to do all this. And aircrew training and mission planning had to be ready in that time as well.

        He wouldn't have got the Hazardous Materials (Waste Disposal) Plan accepted by then if he were doing it today...

        1. AMBxx Silver badge

          Re: It was....

          Don't forget, the technology they were working with then was at a totall different scale to today's. You're not going to create an Intel CPU on your kitchen table. Must have been a great time to own a shed though.

          1. Anonymous Coward
            Anonymous Coward

            Re: It was....

            Someone did make a microchip in their garage earlier this year: Advanced tools and information to use them are easier to come by than ever (though that guy is way out there at the top of the achievement curve). I don't think there's ever been a better time to own a shed.

        2. juice

          Re: It was....

          As the old saying goes, the prospect of being hung (or at least: invaded by a foreign army) does tend to concentrate the mind [*]. Though even then, the Dambusters book makes it clear that Barnes did still have to jump through a lot of hoops to get the bouncing bomb (and later, the tallboys and grandslams) into production.

          As to the "one man invention": technology was considerably simpler and often relied on "brute force", though ironically, today's technology can often deliver far more of a bang for a much smaller buck - and with much greater reliability, to boot. E.g. compare a 1920s race car to a modern road car - both can do the same speed, but the modern car will be far more reliable, easier to drive and probably significantly more fuel efficient, to boot. It's also significantly more complex, and you're far less likely to be able to fix things with a bit of percussive maintenance.

          Even then, and with all due respect for the people who came up with the initial idea, don't underestimate how much of their inventions relied on past discoveries and/or other people's work. For instance, Barnes' grandslams would have been useless without a new steel alloy which could stand up to the forces when ten tonnes of bombs at terminal velocity attempts to drill through a few dozen feet of concrete!

          [*] And the same is true in most industries and scenarios. Code needs to go live tomorrow? Customer billing run failed? JFDI and sort out the paperwork later.

        3. CrackedNoggin Bronze badge

          Re: It was....

          Certainly in second half of the 20th century there were many cases of large scale industrial poisoning throughout the Western world which led to regulations regarding industrial waste. Most of those poisoning were not the result of "innovation" or "inventors" however, they were just the result of deliberately cutting corners to save money.

      2. CentralCoasty
        Black Helicopters

        Re: It was....

        Was talking to someone this week who whilst having a research background is actually an accountant for a government R&D division. His biggest problem is that the items with the biggest returns are normally those that are going to cost a huge amount and/or have a very small chance of success.

        Naturally governments dont like paying R&D to fail as it makes for difficulties come election time.

        Hence the majority of the R&D tends to be on more "safe" ideas where there is a higher chance of a payback.

        I can imagine the situation back in the 40's with the Dambusters. There was limited resources, limited funding - and they wanted to try something new - the bean-counters would have simply gone....

        20 x new bouncing bombs + all new tooling etc to make them (and will they work) vs 1500 existing type bombs (which we know work).

        1. Anonymous Coward
          Anonymous Coward

          Re: It was....

          20 x new bouncing bombs + all new tooling etc to make them (and will they work) vs 1500 existing type bombs (which we know work).

          There was a Arthur C. Clarke short story, can't think it was called now (sorry).

          Earth star fleet want to conquer aliens - both have similar capabilities. A charismatic scientist persuades the government to invest in his super-duper technology - which doesn't work, causes problems and has setbacks. Meanwhile, the aliens with their tried and tested technology successfully conquer the earth.

          Not saying that CentralCoasty is right and that the beancounters get their way, but I often think of that story when some manager has some grand masterplan!

          1. Prst. V.Jeltz Silver badge

            Re: It was....

            "when some manager has some grand masterplan!" it wont be Alien beating technical innovation , i guess it might be productivity enhancing in theory , but most likley that will be down to whipping the slaves harder , rather than anything innovative like storing the giant stones nearer to the pyramid build.

            Most often though it'll just be reverting to the previous masterplan before the current masterplan , which will involve a lot of people swapping desks and renaming the open plan office which is currently named "Centre of Excellence #1" to " Innovation Station #1"

        2. Anonymous Coward
          Anonymous Coward

          Re: It was....

          "20 x new bouncing bombs + all new tooling etc to make them (and will they work) vs 1500 existing type bombs (which we know work)."

          The problem with that was that the existing type bombing didn't work, the RAF knew that but Harris was concealing it even from his own head of service. After the war it was revealed that in terms of actual military effectiveness per £, Mosquitos were nearly 6 times as effective as Lancasters - and Mosquitos nearly didn't happen.

          The Lancaster bankrupted Britain; you could say it was one of the factors in why Germany is now #1 country in Europe.

          1. juice

            Re: It was....

            From what I've read, "Bomber" Harris does seem to have been both resistant to change and overly obsessed with the theory that "strategic bombing" of industrial and political targets (read: cities filled with civilians) would bring Germany to it's knees, despite the fact that Germany had tried the exact same technique on the UK with very limited success.

            "The Lancaster bankrupted Britain; you could say it was one of the factors in why Germany is now #1 country in Europe."

            Really? I found some numbers ( which are a bit odd ("5000 tons of aluminium" per plane sounds a tad dodgy, for starters!), but assuming the headline figures are accurate, it cost approx. £42,000 to buy a Lancaster and £13,000 to send it out for a sortie. Or approx. £1.9 million and £580,000 in 2018 prices.

            Wikipedia then states that approx.7400 Lancs were built, and flew 156,000 sorties.

            Using some basic beer-mat calculations, and assuming that a "sortie" is equivalent to one plane, the manufacturing costs were approx. £15,000 million and the overall running costs work out at about 90,500 million - or around 105 US billion in total

            Finally, states that WW2 cost the UK the equivalent of £1,260,500,000,000 in 2005. Which works out at about £1,830,000,000,000 in 2018.


            So, while the Lancaster bombing sorties were expensive, they were only around half a percent of the total UK war cost.

            The above doesn't take into account secondary costs, such as the training and salary costs for the crew and engineers, but I think it's fairly safe to say that if the Lancaster hadn't existed, those people would have been put to work elsewhere in the war effort (i.e. they'd still require training and paying), so it's somewhat moot in this context.

            1. deeredd

              Re: It was....

              Much more instructive to compare the insane costs of V2's, Me262, various stupid tanks etc.

              Just the V2 bunkers in France cost billions of RMs. Never used.

              Yes Lancasters were a waste but at least they did something and besides everyone was bankrupt by the end except the Yanks

    4. eesiginfo
      Big Brother

      Re: It was....

      ... "Nowadays, for everyone with a new idea, there are 50 or more by-law drafters......"

      You forgot to mention Alphabet and the banks, standing by to suppress your innovation.

      We should never forget that 'all innovation steps on the toes of established corporations'.

      They don't like that.

  8. JimC

    Mather/City and Guilds - Tucker/Imperial

    City and Guilds College (Engineering) and the Royal College of Science (eg Physics) were merged in 1907 (also with the Royal School of Mines) into Imperial College, so Messrs Mather and Tucker would be from the same campus, but rather different parts of the organisation - the constituent colleges retained a fair degree of independence.

  9. Phage

    For those interested in the concept, search for sound tubas.

  10. This post has been deleted by its author

  11. Hans Neeson-Bumpsadese Silver badge

    Good article. I remember mentioning the south coast acoustic mirrors in a comment on a GGTB article a few months back - I didn't realise there were some examples closer to my home up in the north east though. Thanks, El Reg

  12. John Brown (no body) Silver badge

    Fulwell 54.929724, -1.393937

    Thanks for that. I had no idea that was there and shall pop over this afternoon for a look. I must have drive past there 1000's of times. I've even been to the Fullwell windmill.

    Oh, and by the way, did you mean northeast "So why was the northwest, hundreds of miles away, chosen as a site for the sound mirror network?" just after the photo of the Redcar mirror?

  13. Anonymous Coward
    Anonymous Coward

    Family memories

    Interesting to note the first few comments here include memories of family members. Clearly Zeppelins must have been a huge psychological hurdle for civilians, as I thought my own family story is not fully explained. My great-grandmother, from the east end of London, kept a postcard of a Zeppelin in flames in her cupboard. As kids, we loved seeing it, but every time we pestered her to show it to us, her eyes welled up. I then discovered that in 1916, she left London with her two daughters, to move to South Africa, making the trip to Cape Town pretty much at the height of the submarine war, so pretty risky with two kids of 12 and 10. The trauma of the Zeppelin's capabilities must have left real fear. These days, when our "smart bombs" do what 500kg of high explosive do in civilian areas, our news sources dismiss these issues as "collateral damage" or other inhuman euphemisms, so not much has changed.

    1. Lt.Kije

      Re: Family memories

      The first time in the history of mankind than a huge machine appears overhead to rain down death with impunity. The impact on the population must be about the same as as a spaceship appearing and doing the same today.

      1. Alumoi Silver badge

        Re: Family memories

        The impact on the population must be about the same as as a spaceship appearing and doing the same today.

        Naah, we all know somebody will fly an old alien fighter up to the mothership and install a virus.

      2. Anonymous Coward
        Anonymous Coward

        Re: Family memories

        The first time in the history of mankind than a huge machine appears overhead to rain down death with impunity. The impact on the population must be about the same as as a spaceship appearing and doing the same today.

        Or they will just watch it on TV and complain about the crappy special effects!

      3. CrackedNoggin Bronze badge

        Re: Family memories

        Machine overhead yes. But the Mongols are documented as catapulting plague infested corpses into a city under siege in 1346. They were also known to launch in pots of boiling tar and other unpleasant things.

  14. This post has been deleted by its author

  15. Anonymous Coward
    Anonymous Coward

    Perhaps another jaunt is in order

    There are some more sound mirrors at Abbott's Cliff near Folkstone.

    Anyone know of any others?

  16. Oddbodd

    Schoolboy error

    Middlesbrough, not Middlesborough.

  17. Stevie


    A new military technique, one based on sound?

    Then what we have here are the world's first Weirding Modules.

  18. Dave 15


    Seems the Germans were still using this in ww2.

    Given the supposedly wonderful anti radar abilities of todays ships and aircraft could there be a use for it again. Now obviously an aircraft at mach 1+ is coming faster than its sound waves but I believe they often cruise slower... by using sound detection to force them to go fast they will run out of fuel quicker and have to return home (in the case of that useless American junk we have bought probably sometime before it reaches the end of the airfield).

  19. ridley


    I cannot help wondering if you could make a better use of a drone than to fly one in front of these mirrors and see if they work and if so how well.

  20. Phage

    Open day on the South Coast ones coming up

  21. LeahroyNake

    Sound is still useful

    Counter Bombardment and Counter Mortar Battery Equipment. Is still in use today to pinpoint enemy mortar fire locations.

    No doubt based on these concrete structures but using modern microphones and computers.

    Nice link here for modern adaptations...

    Very nice article, next to BOHF these keep me coming back.

    1. Destroy All Monsters Silver badge

      Re: Sound is still useful

      Solzhenitsyn wrote about his service in the Soviet Army as operator on an acoustic direction & ranging in an Arty brigade: "At the Jeliabuga hamlet" (Zelâbugskie vyselki) in Deux récits de guerre. I must be about 60km from Orel, it's not the Yeliabuga in Tatarstan ... I didn't find it on Google Maps. Next to Setoukha and Blagodatnoïé. Didn't find those either.

      He's talking about a "Fenyuchkine Computer" that corrects for wind speed, temperature & hygrometrics. No idea what that is. Something for the Computer Museum to clarify.

  22. John Smith 19 Gold badge

    I can't help feeling there's the germ of a Charles Stross story here....

    The one in the South being real acoustic Zeppelin detectors.

    The ones up North serving a more occult purpose......

  23. Anonymous Coward
    Anonymous Coward

    And as a follow on (as well as mentioning this technology and how it was superseded) Most Secret War by R.V. Jones is a very informative read.

  24. earl grey

    Thank you

    Very interesting article.

  25. Destroy All Monsters Silver badge


    That concrete sound mirror looks like a cargo-cult version of a phased array radar.

    But while we popularly imagine the conflict as confined to the trenches of Flanders

    ...not forgetting about the trenches and deep manoeuvering on the Eastern Front or the senseless slaughter on the italian front in the imperialist freakshow.

  26. GrumpyKiwi

    South East post-war detectors

    Pretty sure I read that these were positioned there because the only likely Post-WW1 enemy the RAF could think of was ... France.

    The stiff upper lips of the newly formed RAF were 100% that morale of the Froggie civilians would collapse from bombing long before our sterling British civilians. But just to be sure, plans were made to deploy the army in working class parts of SE cities.

  27. TDog

    Tucker Microphones

    I spent quite a lot of time about 5 years ago researching this technology as it is a fascinating pre digital computer process. The 'microphones' were actually pressure transducers and an arc of about 6 of these would be placed behind the observation post and connected to it by wires.

    When the observer heard a sound of interest he would press a button. This started a cine camera running that would record the 6 galvanometers attached to the transducers. These would kick when the pressure wave hit the transducers and this was recorded on film. The film was automatically developed and printed (in 1916 / 17!) and the time delays were recorded.

    An analogue computer consisting of a board with pins in the positions of the transducers and string attached to each pin was used by simply choosing a length of string proportional to the sound delays - where all the six strings intersected was where the sound had originated. As the observer started the process when he heard the sound of the shell exploding the sounds that hit the transducers when recording was the sound of the guns firing.

    This was how the silent pre-registration of the suppressive artillery barrage at the battle of Cambrai was planned; it prevented over 80% of the German batteries from performing their defensive roles in 1917.

    By mid 1917 the system was so effective that it was being used to calibrate individual guns for barrel wear to allow corrections to be made.

    Fascinating to me.

    1. GrumpyKiwi

      Re: Tucker Microphones

      A +1 and a "thank you" for the explanation.

    2. Goobertee

      Re: Tucker Microphones

      Wow. Just wow. I read the modern stuff and, for better or worse, understand a lot of it because of what I did for 40 years. But I read articles like this and some other technologies from the last century and before, sitting there thinking they could not have done all of that back then--but they did.

      Thank you, TDog, for sharing.

    3. TDog

      Re: Tucker Microphones

      One other tad of information - the microphones were basically kilner jars - chosen because of the large opening at the top with the platinum wire inside. The large opening and volume made them relatively insensitive to high frequency changes but the low frequency pulses of air caused sufficient displacement to cool the transducers.

      It took me ages to find that out - I kept looking for information on microphones...

      1. John Smith 19 Gold badge

        the microphones were basically kilner jars

        This is very impressive.

        How do you do signal processing before people did signal processing?

        This is how.

        Quite staggering in an era where people would be thinking "FFT," or lower level analogue filter banks.

      2. Uffish

        Re: Tucker Microphones

        Many years ago one of our teachers, he of the two tin legs, described the spaced microphone system. He said the hot wire sensors were mounted on Helmholtz resonators, whether made of kilner jars or not, he didn't say. He also said that the time of arrival to distance plotting was done with horse tail hairs. It is really good to have this more complete information after 60 years.

  28. deadlockvictim

    Zeppelin museum

    The Zeppelin museum in Friedrichshafen on the shores of Lake Constance is also well worth a visit. They have parts of the Zeppelin that exploded in the U.S. (Oh, the humanity!) and it gives an idea of how massive they were.

    The German engineers wanted to use helium but a U.S. embargo put an end to that. Furthermore, although the Zeppelin company was the epitome of luxury at the time, they never made much money. They were also opposed to Mr. Hitler's regime and reluctantly agreed to have swastikas painted onto the Zeppelins in order to ensure the survival of the company.

  29. trsanford

    Many reference works available to a child in 1950 (like me) carried detailed accounts of pre-WWII weaponry. I remember seeing pictures of a good many exponential horns, often mounted on wheels, for use as acoustic detectors and direction finders. Your article is the first mention I've ever seen of paraboloidal reflectors used for that purpose.

    I do hope someone is documenting all this stuff thoroughly, before it vanishes and is completely forgotten.

  30. Unicornpiss


    It sounds (no pun intended) like Tucker actually invented the first MAF or "mass air flow" sensor, used commonly in automotive applications to determine the amount of air being consumed by an engine, and adjust the fuel/air ratio accordingly, although his application of it was obviously different.

    I wonder if you could replicate his efforts in filtering low-frequency sound by using a spare MAF from a vehicle, if so inclined..

    1. TDog

      Re: Tucker..

      I suspect it may be slightly more difficult to provide the 60 medium and heavy artillery pieces per mile of front...

      I rather think I played with early MAF sensors (were they the same things as 'Fleisch' sensors (spelling from memory) which utilised the same principle as a heated grid through which the air passed and measuring the delta resistance?

      I was young then, and at the IAM Farnborough.

  31. Anonymous Coward

    Naval gazing

    I am not sure about this but I suspect a lot of the reason for Zeppelin attacks on the north was naval: if you can attack Sunderland, especially if you can do so with less warning than it takes a dreadnought to raise steam (which was hours) then you can't keep the Grand Fleet -- or even a significant detachment of it -- that far south without risk of loss. This helps to ensure is that they end up in Scapa Flow with some down at Rosyth, making the North Sea safer for the High Seas Fleet (which in turn could then raid the same ports, as they did). The Germans desperately wanted to avoid a full-scale fleet action, which they assumed they would lose, which would be very bad for them. I don't think anyone expected Jutland to be so inconclusive, although if we had been coming from further south and thus met the HSF earlier in the day it probably would not have been.

    A mad alternative theory for these mirrirs might be that they were intended to listen for ships (I'm sure this is wrong: they were obviously built to listen for Something Nameless rising from the North Sea.)

  32. CrackedNoggin Bronze badge

    AFAIK sound is still the only way to detect submarines underwater. Also

    "A humpback whale singing in the Caribbean, for example, can be heard by a fellow whale off the west coast of Ireland more than 4,000 miles away. Eighty-foot-long fin whales — second only in size to the blue whale — can make low-frequency moaning sounds beyond the range of human hearing that also travel thousands of miles." [ ]

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