About Charles Cagniard de la Tour
Baron Charles Cagniard de la Tour was a French engineer and physicist. Charles Cagniard was born in Paris, and after attending the École Polytechnique became one of the ingénieurs géographiques. He examined the mechanism of voice-production, invented a blowing machine and contributed to quantitative acoustics by inventing an improved siren. He also studied yeast. In 1822, he discovered the critical point of a substance in his gun barrel experiments. He invented the improved siren, which was named after him, around 1819 and he used it for ascertaining the number of vibrations corresponding to a sound of any particular pitch.
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