This is one of those devices that one comes across
casually and forgets only to stumble over it again decades later.
In the 1950s & '60s, Professor Vladimir Gavreau of France's
Electro-Acoustical Laboratory in Marseille noticed that low-frequency
vibrations in his laboratory's new ventilation system made people even
sicker than those horrible paintings of puppies with huge eyes and he
concluded that ultra-low frequency sound waves of about 10 Hz were
just the ticket for creating a sonic death ray.
With typical Gallic logic, Gavreau constructed an
apparatus consisting of a high-pressure air hose hooked up to a sort
of whistle that apparently had a rather dramatic effect. Said
Luckily, we were able to turn it off quickly.
All of us were sick for hours. Everything in us was vibrating:
stomach, heart, lungs. All the people in the other laboratories were
sick too. They were very angry with us.
When accounts of this machine leaked into the
popular press, it was through a handful of sensational articles that
described how the French were building a sonic death ray cannon that
consisted of a framework of compressed-air whistles eighteen feet
across that could kill stone dead any human being at a range of five
miles and crack open battle tanks like walnuts. When nothing
like this ever turned up on the army parade grounds, it was put down
to the prototype being too dangerous to operate and that all records
had been sealed by the French government for no readily apparent
reason; never to be seen again except on obscure conspiracy web pages.
It was quite a neat story and when I first saw the alleged canon
sonique on a magazine cover back in the '70s the
photographer had angled the camera so that the thing looked huge.
It looked like it was mounted on the back of a gigantic lorry and was
ready to roll into battle--or away, given that this was a French
weapon. Whether or not it worked, it was impressive. Then
I recently ran across the above photo of Prof. Gavreau and his brain
child and it turns out that his infernal machine was about the size of
a tea tray.