Annals of medical history . a letter to George Wheatly, datedPassy, May 23, 1785, Benjamin Franklindescribes and illustrates a pair of bifocalglasses which he had had made for his useby Doliond, the famous optician of why this useful invention of Franklinswas allowed to lapse into obscurity formany generations after its discovery, isnot known. One would think that a prac-tical optician such as Doliond would havegrasped its value, and that its usefulness. through which a man sees clearest and best atthe distance proper for reading, is not the bestfor greater distances. I therefore h
Annals of medical history . a letter to George Wheatly, datedPassy, May 23, 1785, Benjamin Franklindescribes and illustrates a pair of bifocalglasses which he had had made for his useby Doliond, the famous optician of why this useful invention of Franklinswas allowed to lapse into obscurity formany generations after its discovery, isnot known. One would think that a prac-tical optician such as Doliond would havegrasped its value, and that its usefulness. through which a man sees clearest and best atthe distance proper for reading, is not the bestfor greater distances. I therefore had formerlytwo pair of spectacles, which I shifted occasion-ally, as in travelling I sometimes read and oftenwanted to regard the prospects. Finding thischange troublesome, and not always sufficientlyready, I had the glasses cut, and half of eachkind associated in the same circle, thus . .By this means, as I wear my spectacles con-stantly, I have only to move my eyes up ordown as I want to see distinctly far or near, the. so easily demonstrated, would have intro-duced it at once into popular , following his invariable custom,did not patent his idea, so that there wasno restriction on Dollc^nd or any otheroptician who wished to make such lenses. By Mr. Dolionds saying that my doublespectacles can only serve particular, I doubt hehas not been rightly informed of their con-struction. I imagine it will be found prettygenerally true that the same convexity of glass proper glasses being always ready. This Ifind more particularly convenient since mybeing in France, the glasses that serve me bestat table to see what I eat, not being the best tosee the faces of those on the other side of thetable who speak to me; and when ones cars arenot well accustomed to the sounds of a language,a sight of the movements in the features of himthat speaks helps to explain; so that I understandFrench better by the help of my spectacles.—The ^Works oj Benjamin Franklin, Philadelphia, 1852
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Keywords: ., bookauthorp, bookcentury1900, bookdecade1910, booksubjectmedicine
