1 gen 1752 anni - Eyeglasses and Flexible Catheter

Descrizione:

The earliest known document mentioning concave lenses being used for correcting myopia was a letter from the Duke of Milan to his ambassador in Florence ordering three dozen eyeglasses, including "a dozen that are suitable for near vision, that is for the elderly." (nytimes)

Benjamin Franklin invented the flexible catheter, made of hinged metal segments, for his brother John, who suffered from bladder stones. Previously, catheters had been hard tubes, jammed into the bladder through the urethra (nytimes).