The Japanese War Tuba
Just kidding, it's actually an acoustic locator used by the Japanese military in WWII. It's a device they used to "hear" the distant engine noise of oncoming airplanes. Acoustic locators like this were used from mid-World War I through the early days of World War II, until the invention of radar made them obsolete.
More neat pics at the [a href="vny!://www.dself.dsl.pipex.com/MUSEUM/COMMS/ear/ear.htm"]Acoustic Radar[/a]
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