In a concession to advancing age Franklin had taken to using two sets of eyeglasses, one for close work, the other to see things at a distance. This was never convenient, but Franklin found it particularly irksome in traveling, when he would shift his gaze from a book or paper he was reading to a distant object he wished to observe. After considering the matter for some time, he directed his optician to take one pair of each of his spectacles and cut the lenses in half horizontally. Two each of these half-lenses were then fitted together in a single set of wire frames, with the farsighted
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