I saw this thing floating around on the archived "mystery sirens" topic, and I don't think anyone ever figured out what this thing was.
However, *I figured out what this thing was, and while I have shared it around on Facebook and Discord, I have yet to post it here, so I'm gonna do that.
The "Mystery Siren" that was located in Cameron, Missouri is what is known as the Sterling "Super Quad" siren. It was a variant of the Model "M" that utilized a 12 horsepower electric motor to drive a set of 4, 14" Mod. M impellers.
They started making these in around 1922, and while I do not know when they stopped making them, the siren was produced at least up until 1925. Very few Super Quads were ever sold, due to them being extremely expensive for their time (todays equivalent of ten thousand dollars).