An essay on visual glasses, (vulgarly called spectacles) wherein it is shewn ... that the common structure of those glasses is ... very prejudicial to the eyes; the nature of vision in the eye explained, and glasses of a new construction proposed / [Benjamin Martin].

  • Martin, Benjamin, 1705-1782.
Date:
1757
Catalogue details

Licence: Public Domain Mark

Credit: An essay on visual glasses, (vulgarly called spectacles) wherein it is shewn ... that the common structure of those glasses is ... very prejudicial to the eyes; the nature of vision in the eye explained, and glasses of a new construction proposed / [Benjamin Martin]. Source: Wellcome Collection.

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    This Invention being of fo great a Con¬ cernment to Mankind in general, will certainly command their Attention to every Propofal for its Improvement; though it muft be confefled there has fcarcely any thing been done fince they were firft made that delerves to be fo efteemed; perhaps no optic Inftrument has been fo little considered or altered fince the firft Conftrudtion, as Spectacles. The Maker or Seller is not to be charged with this Negledt y but the Optician (I mean a Perfon fkilled in the The Theory of Optics) who, though he has eondefcended often to treat of the Subjedl, has never yet pointed out the beft Method of con- ftrudting them for Ufe, nor even fo much as taken notice of that very Form and Difpofition of Glades in this Inftrument, which the Science of Optics points out, and makes neceftary to their Perfection. Among others, I myfelf have over-looked the Nature of this Inftrument, till it fell into my Way to be more nearly interefted in the Ufe of it. I before looked on it only as an ufeful Dedudtion from this Science, to others y but my own Eyes now beginning to require their Afiiftance, I began more particularly to confider them, and efpecially how and in what Manner they might be applied to the beft Ad¬ vantage for the Eyes, as I well knew the Man¬ ner in which Light affedfeed that noble Organ. I had not long reftedted on the Subjeft,when I eafily perceived the Errors of the common Form;