Ramananda Sengupta explains how 'crap cannons' can be an effective mob-control weapon.
Imagine a sonic weapon that could make everyone within a 100-metre radius involuntarily evacuate their bowels.
Now imagine the impact that would have on a frenzied mob storming an embassy or a police station; or a crowd of stone-throwers in Kashmir.
It has been variously described as a 'crap cannon' or 'brown note'. It has also been debunked as an urban myth.
But sound, however, can be and has been used often as a weapon. And no, we are not talking about the loud bass at rave parties which has been known to induce heart attacks or collapse the lungs of those standing too close to the speakers.
We are not even talking about Heavy Metal, used to good effect in places like Guantanamo to soften prisoners unused to such sounds before interrogation.
More recently, Long Range Acoustic Devices, or LRADs, have been used effectively against pirates off the coast of Somalia.
Then there's infrasound, which can scare the living daylights out of most of us, literally.
'Sound can be deployed to produce discomfort, express a threat, or create an ambience of fear or dread to produce a bad vibe,' says the introduction to Sonic Warfare: Sound, Affect, and the Ecology of Fear, by Steve Goodman, lecturer in music culture at the University of East London.
'Sonic weapons of this sort include the 'psychoacoustic correction' aimed at Panama strongman Manuel Noriega by the United States army and at the Branch Davidians in Waco by the Federal Bureau of Investigation; sonic booms (or 'sound bombs') over the Gaza Strip, and high frequency rat repellents used against teenagers in malls,' Goodman adds.
Ghost in the Machine, (not to be confused with Arthur Koestler's book, or the album by The Police) is a fascinating paper published in the Journal of the Society for Psychical Research back in 1998, by Vic Tandy and Tony R Lawrence of Coventry University.
Tandy had a personal experience with this 'ghost' while working in his lab, which produced life support and intensive care equipment. Workers there would often feel uneasy, and report sensing a 'presence' out of the corner of their eye, which would disappear the moment you looked directly at it.
According to the paper, 'As time went on, VT (Tandy) noticed one or two other odd events. There was a feeling of depression, occasionally a cold shiver, and on one occasion a colleague sitting at the desk turned to say something to VT, thinking he was by his side. The colleague was surprised when VT was found to be at the other end of the room. There was a growing level of discomfort but the workers were all busy and paid it little attention.'
'VT was working on his own one night after everyone else had left. As he sat at the desk writing, he began to feel increasingly uncomfortable. He was sweating but cold and the feeling of depression was noticeable. The cats were moving around and the groans and creaks from what was now a deserted factory were "spooky," but there was also something else. It was as though something was in the room with VT.'
'There was no way into the lab without walking past the desk where VT was working. He looked around and even checked the gas bottles to be sure there was not a leak into the room. There were oxygen and carbon dioxide bottles and occasionally the staff would work with anaesthetic agents, all of which could cause all sorts of problems if handled inappropriately. All of these checked out fine so VT went to get a cup of coffee and returned to the desk.'
'As he was writing, he became aware that he was being watched, and a figure slowly emerged to his left. It was indistinct and on the periphery of his vision but it moved as VT would expect a person to. The apparition was grey and made no sound. The hair was standing up on VT's neck and there was a distinct chill in the room. As VT recalls, "It would not be unreasonable to suggest I was terrified".'
'VT was unable to see any detail and finally built up the courage to turn and face the thing. As he turned the apparition faded and disappeared. There was absolutely no evidence to support what he had seen so he decided he must be cracking up and went home...'
The next morning, Tandy arrived early to work to fix a foil blade he needed for a fencing match he had entered. Locking the rapier in a vice, he went to find a bit of oil. When he returned a few minutes later, he was startled to find the blade 'frantically vibrating up and down.'
A little experiment revealed that the vibration was caused by ultrasound emitted by an exhaust fan, which had turned into a 'low frequency standing wave.' The moment the fan was stopped, the blade stopped vibrating. And the atmosphere in the lab became measurably lighter.
Infrasound, says the Skeptic's Dictionary, refers to extreme bass waves or vibrations, those with a frequency below the audibility range of the human ear (20 Hz to 22 kHz).
Even though these waves can't be heard by us, they can be felt and have been shown to produce a range of effects in some people including anxiety, extreme sorrow, and chills.
And sounds between 7 and 19 Hz could induce fear, dread or panic. But what about the apparitions?
A study by the National Aeronautics and Space Administration on infrasound asserts that the higher end of that spectrum (closer to 19Hz) can resonate with the average human eyeball, leading to 'smeared' vision, where the eye vibrates just enough to register static objects -- like the frame of VT's spectacles, or even a speck of dust -- as large, moving shapes.
This study helped VT crack the haunting of a nearby abbey, which had spooked several people. The culprit: Infrasound again, caused not by a mechanical device, but naturally due to wind in the corridors and tunnels of the abbey.
So sound can be used to scare people shitless.
Why not use it instead of, or alongside, the pellet guns which apparently blind protestors and stone throwers in Kashmir?
Before writing this column, I discussed it with a friend who works for a government defence lab. While expounding the possibilities of an 'oily foam' which when sprayed on protestors prevents them from walking or running without slipping and falling on their butts, he was extremely sceptical over whether sound could indeed cause people to soil their pants.
However, he said, with a thoughtful gleam in his eye, "certain gases certainly can."
Investing in the adult diaper industry suddenly makes sound business sense.