The 1819 siren makes sound via rapid air puffs from a rotating disk

Evidence

The siren, developed in 1819, is credited to the French physicist Baron Charles Cagniard de la Tour (1779–1859). A siren is a wonderfully straightforward device, an almost self-explanatory way of making sound. The idea is to cause puffs of air to be emitted in rapid succession. This is done with a hose containing compressed air, stopped by a rotating disk with holes that rotate into place in front of the hose to release a puff of air (figure 7.18). — Eric J. Heller, Why You Hear What You Hear- An…, 581

Categorization

• DEFINE: Explains the siren’s mechanism: a perforated rotating disk chops compressed air into rapid pulses.
• XREF: Mechanical sound-sourcing mechanisms connect to chapters on percussion and wind-driven sound sources.