Q:

When did Benjamin Franklin invent bifocals?

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Quick Answer

Benjamin Franklin invented bifocals in 1784. As announced in a letter to a friend, he called the new invention "double spectacles." The glasses allowed a person to see far or near, depending on what part of the lens they were looking through.

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Full Answer

Although Franklin is credited with the invention, historians are unsure if he truly created them or if he had them built by someone else. Franklin ordered specialty eyeglasses while in France on a diplomatic mission in 1779, and he paid a large sum of 18 francs for them, leading some historians to believe these were the bifocals in his letter. Franklin suffered from an eye condition called presbyopia, which makes it difficult for the eye to focus on images up close. Eye doctors prescribe bifocal lenses to patients with this eye condition.

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    Who invented bifocals?

    A:

    Benjamin Franklin invented bifocals. In a letter to his friend George Whatley in 1784, Franklin dubbed the bifocals "double spectacles." They are made by combining convex and concave lenses so that both nearsighted and farsighted vision can be corrected by the same glasses.

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    When did Benjamin Franklin invent the lightning rod?

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    Benjamin Franklin invented the lightning rod in 1749 while conducting experiments with electricity. Since Franklin’s invention, lightning rods have been mounted on elevated buildings and other tall structures to prevent fire damage and electrocution.

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    What are some of Benjamin Franklin's inventions?

    A:

    Some of Benjamin Franklin's inventions include the lightning rod, bifocal eyeglasses, the glass armonica and the Franklin stove. Benjamin Franklin is also credited with creating the odometer and the first political cartoon in American history.

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    How did Benjamin Franklin change the world?

    A:

    Benjamin Franklin changed the world by helping write the Declaration of Independence and U.S. Constitution, negotiating the end of the Revolutionary War with the Treaty of Paris and becoming the first ambassador of the United States to France. He also had notable achievements as a publisher, author, scientist and inventor.

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