Deafness practically illustrated / [James Yearsley].

  • James Yearsley
Date:
[1849]
Catalogue details

Licence: Public Domain Mark

Credit: Deafness practically illustrated / [James Yearsley]. Source: Wellcome Collection.

    184/200 page 172
    CHAPTER Ix. EAR TRUMPETS. To many among the deaf, an ear trumpet will be inva- luable. It is a mechanical contrivance analogous to the spectacles worn by persons whose sight is too long, too short, or which is become enfeebled by age; but from an unworthy prejudice, or from its drawing upon the wearer so much observation, the description of ear trumpet by which alone assistance can be derived is rarely made use of. Advantage has been taken of this prejudice, and inventions the most absurd have been proposed to obviate the objection. But it may be set down as an axiom, that the value of an ear trumpet consists in its power of collecting, concentrating, and directing to the outer passage of the ear, a greater quantity of sound than could reach it without such aid. The inutility of small instruments must therefore be evident. To give a minute description of the endless variety of instruments proposed for the use of the deaf would be a waste of time, more especially as the great majo- rity of them are utterly useless and inefficient. Ear trumpets of the most varied forms have been con- structed, some straight, some bent, some coiled, others conical or parabolical, almost all capable of collecting sound and directing it to the ear; but, unfortunately, this is not the only requirement. Comiers speaks of an
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