Jamming with a 150 year-old Helmholtz siren (and other vintage sirens)

Bram writes to direct me towards this wonderful, strange and geeky clip of a Helmholtz Double Siren in action - it's a little wood and brass gadget powered by compressed air, which was used by Hermann von Helmholtz in the 1860s while he was researching is interesting-sounding book 'On the Sensations of Tone as a Physiological Basis for the Theory of Music' It comes across half way between Goodiepal and this guy.
Incidentally, there's quite a thriving community of people who collect and restore vintage police/fire sirens - There's Siren Man (warning, some pages play sound files), who sells police sirens for up to $750, and here's a great feature about the scene by Michael Lamm: "I felt as though I could reach out and touch the sound, or lean on it or even sit on it, maybe even pick it up with a shovel or swim in it."

Finally, here's the genius of Bill Bailey on Foreign Police Sirens.