A Look Back Through Benjamin Franklin's Lenses

In honor of the United States’ 250th anniversary, let's take a look at one of the most widely used inventions by one of our founding fathers, the bifocals. Benjamin Franklin invented bifocals or “Double Spectacles,” as he called them, in 1785, detailing his construction of them in a letter to his friend, George Whatley. While not the most action-packed and shocking invention of his, (haha,) It’s believed that the roots of the precursor of his innovations, the eyeglasses, can be traced all the way back to the invention of reading stones by 9th century Andalusi polymath and inventor, Abbas ibn Firnas, and the popularization of the concept of vision correction in the “Book of Optics” by Ibn al-Heitam. 

These stones were small quartz, beryl, or glass stones placed on a surface for magnification. In the 12th century, the use of reading stones became widespread once Ibn al-Heitam’s piece was translated into Latin and made accessible to European monks. Evidence that the concept of spectacles being held in front of the face became prevalent sometime during the end of the 13th century in Florence, Italy. These spectacles consisted of quartz lenses housed in horn or oak and were held up to the face rather than worn. During the 15th and 16th centuries, eyeglasses transitioned to being made primarily from metal and toted around by “spectacle peddlers.” 

In his letter to Whatley, Franklin details his disdain for the need to switch between two different glasses when reading and going about his daily life, calling the concept of having two pairs of glasses “troublesome and not always sufficiently ready.” Franklin’s “Double Spectacles” proved especially useful for this purpose, and also, notably, during his time at the dinner table! Franklin, at the time of his writing, was operating out of Passy, France. Franklin spoke French, but was far from fluent, leaning more towards nonverbal communication in his foreign affairs, the bifocals enabling him to gauge expressions from French collaborators across the table from him, whilst simultaneously being able to look down at the table and see his food.

Franklin did not patent his concept of bifocals, as he was famously against the concept of patenting his inventions, but a myriad of other patents have emerged over the years, innovating different facets of their production and design. Sorry, Ben, hopefully there are no hard feelings between us. Happy Fourth of July!

"Benjamin Franklin" c. 1785 Franklin's Letter and sketch to George Whatley