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How did the ancient hydraulis use water pressure to operate its pipes?
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wind instrument
The Japanese end-blown flute, or shakuhachi.
The hydraulis was the earliest known mechanical pipe organ, invented in the 3rd century BCE to provide a steady wind supply for its pipes.1
The instrument utilized a conical wind reservoir placed inside a tall outer container that was half-filled with water. Air was pumped into the reservoir to supply the wind chest, which sat atop the reservoir and held the pipes. The water served as a pressure-regulating mechanism: when the air pressure within the cone dropped, the water level inside the cone rose, compressing the air and restoring the necessary pressure to ensure the pipes sounded evenly.1
By maintaining this consistent air pressure, the hydraulis was able to produce a loud and penetrating sound suitable for outdoor public entertainment.1