10 giug 1752 anni - Invention of Bifocals
Descrizione:
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.Aggiunto al nastro di tempo:
Data:
10 giug 1752 anni
Adesso
~ 273 years ago