Lip whistling stumped nineteenth-century acousticians as a causal puzzle

Evidence

The cause of sound in a lip whistle is one of the most perplexing problems in acoustics. Savart says it is the result of alternate rarefactions by the hot breath, and subsequent compressions by atmospheric pressure. This explanation, however, with all due deference to so honored a name, cannot be admitted, inasmuch as the sound can be imitated mechanically without the aid of hot vapor. The whistling through cracks and keyholes seems to be an analogous phenomenon. — Eric J. Heller, Why You Hear What You Hear- An…, 1318

Categorization

• QUESTION: Historical note worth chasing: how was lip-whistle sound generation eventually explained via vortex/flue mechanisms?
• CANDY: A quotable 19th-century acoustics mystery; Savart’s hot-breath theory is delightfully wrong yet argued with deference.