Information about benjamin franklin bifocals images

American statesman, author, and inventor Benjamin Franklin was a man with so many skills and disciplines he seemed to touch almost every aspect of early American life. Known for his innovations and experiments including the Franklin stove, the lightning rod, bifocals and daylight savings time, Franklin often comes to mind in June for his most famous experiment. On June 10, 1752 he flew a kite with a key attached to it during a storm to prove that lightning and electricity were the same.

Sometimes overlooked in the multiplicity of his talents are Franklin’s contributions to the history of medicine. In 1751, Franklin and Thomas Bond, an American physician and surgeon, established Pennsylvania Hospital, the first hospital in what was to become the United States of America. In 1752, Franklin invented the first flexible urinary catheter—for his brother, who suffered from kidney stones. Though his device was a modification of a European catheter, Franklin’s catheter remains the first of its type created in America.

Franklin’s vision deteriorated as he grew older. He was both myopic (near-sighted) and hyperopic (far-sighted). An avid reader, he grew tired of switching between two pairs of glasses—one that helped him see close up and another that improved his distance vision. In 1785, he had the lenses from his two sets of glasses cut in two horizontally and mounted back into spectacle frames, with the lens for close work at the bottom and the lens for distance at the top—the first bifocals.

The Benjamin Franklin portrait and thousands of other images from the Library’s collection can be found in the Images from the History of Medicine database

A man of many talents, Benjamin Franklin was not one to back down from a challenge – even if that challenge was defying age. As he grew older, Franklin’s vision, which had never exactly been amazing, began to deteriorate to the point where his glasses no longer helped. Needing, now, to carry around two pairs of glasses, Franklin quickly became annoyed and set his mind to solving the problem. The result… Benjamin Franklin invented the bifocals. 

Benjamin Franklin the Scientist

The bifocals, or double spectacles as he called them, weren’t Franklin’s first foray into optics. For decades, Franklin had been interested in telescopes. Having made a name for himself as one of America’s more scientific thinkers, Franklin opened correspondence with leading opticians in the colonies and England.

For the better part of three decades Franklin played the role of middleman between opticians on either side of the Atlantic. As several of letters show, Franklin helped communicate the advances each of these men made with each other. Whether it was the shape or materials used in making lenses, or the hardware needed to make telescopes more useful, Franklin was all up in it.

In January, 1764, James Bowdoin, a leading astronomer, wrote to Franklin from Boston for his help improving a telescope. In this correspondence, Bowdoin asked Franklin to send his latest ideas on telescopes to John Canton, a leading English physicist of the day.

“I here enclose, open for your perusal, a Letter to Mr. Canton on the Subject I spoke to you about, Bowdoin wrote. “If any thing should occur to you to improve the Telescope further than what is noticed in said Letter, I shall take it as a favor you would mention it to Mr. Canton; and that you’d be so good as to let my letter accompany your own.”

Along with the letter, Bowdoin included an image of the telescope he wanted Franklin’s help in improving:

But, from Bowdoin’s letter, we can also see Franklin

In a letter dated May 23, 1785, Benjamin Franklin reveals his design for what would later be called bifocal glasses. The Pennsylvania inventor, printer, author, diplomat and American Founding Father had grown tired of alternating between two different pairs of glasses to help his near or far vision. So he came up with an idea to, quite literally, split the difference. Franklin is widely credited as the inventor of bifocals.

In the letter to his friend George Whatley, a London merchant and pamphleteer, Franklin includes a sketch of his new invention, saying that he found the bifocals particularly useful while dining in France. With them, he wrote, he could see both the food he was eating and the facial expressions of people seated across the table, which helped him better interpret their words—crucial for a diplomat navigating a foreign country.

“I therefore had formerly two pair of spectacles, which I shifted occasionally, as in travelling I sometimes read, and often wanted to regard the prospects,” Franklin wrote. “Finding this change troublesome…I had the glasses cut, and half of each kind associated in the same circle. By this means, as I wear my spectacles constantly, I have only to move my eyes up or down, as I want to see distinctly far or near, the proper glasses being always ready. ”

The bifocal sketch came the year after Franklin made a special request to his optician: Slice in half the lenses of his reading glasses and long-distance glasses, then combine them together with the distance lenses on top and reading glasses on the bottom. Franklin called the glasses style “double spectacles,” later known as bifocals.

Like with his other inventions—including the lightning rod, swim fins and urinary catheter—Franklin had little interest in making money. He wanted his bifocal breakthrough to help other members of the community struggling with vision deterio

Eyeglasses with two distinct optical powers

For the bifocal tensor, see Fundamental matrix (computer vision).

Bifocals are eyeglasses with two distinct optical powers correcting vision at both long and short distances. Bifocals are commonly prescribed to people with presbyopia who also require a correction for myopia, hyperopia, and/or astigmatism.

History

Benjamin Franklin is generally credited with the invention of bifocals. He decided to saw his lenses in half so he could read the lips of speakers of French at court, the only way he could understand them. Historians have produced some evidence to suggest that others may have come before him in the invention; however, a correspondence between George Whatley and John Fenno, editor of the Gazette of the United States, suggested that Franklin had indeed invented bifocals, and perhaps 50 years earlier than had been originally thought. On the contrary, the College of Optometrists concluded:

Unless further evidence emerges all we can say for certain is that Franklin was one of the first people to wear split bifocals and this act of wearing them caused his name to be associated with the type from an early date. This no doubt contributed greatly to their popularisation. The evidence implies, however, that when he sought to order lenses of this type the London opticians were already familiar with them. Other members of Franklin's circle of British friends may have worn them even earlier, from the 1760s, but it is at best uncertain (and arguably improbable?) that split bifocal lenses had a famous gentleman inventor. Since many inventions are developed independently by more than one person, it is possible that the invention of bifocals may have been such a case.

John Isaac Hawkins, the inventor of trifocal lenses, coined the term bifocals in 1824 and credited Benjamin Franklin.

In 1955, Irving Rips of Younger Optics crea