10 jun 1752 año - Invention of Bifocals
Descripción:
In 1752, Benjamin Franklin invented bifocals. Bifocals are glasses with transitional lenses that allow people who are both farsighted and nearsighted to maintain their vision with one pair of glasses, and while they have been upgraded, they are still used today.
Añadido al timeline:
fecha:
10 jun 1752 año
Ahora mismo
~ 273 years ago
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