Acoustics: a carbon microphone invented by D.E. Hughes. Wood engraving by Baud after Broux.

    • Broux.
    Reference:
    47038i
    Catalogue details

    Licence: Public Domain Mark

    Credit: Acoustics: a carbon microphone invented by D.E. Hughes. Wood engraving by Baud after Broux. Wellcome Collection. Source: Wellcome Collection.

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