This tuba-like device was actually the Japanese military's acoustic locator - a device with which one can "hear" distant engine noise of oncoming airplanes.
Acoustic locators like this (and others) were used from mid-World War I through the early days of World War II, until the invention of radar made them obsolete.
Japanese War Tuba [wiki] | More neat pics at: Acoustic Radar
Newest 1 Comment
Great photo - and the link to "Acoustic Radar" was quite informative as well. Thx.
Abusive comment hidden. (Show it anyway.)