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Ten things you ought to know about old Ben.

1. He petitioned Congress to abolish slavery. In February 1790, Franklin wrote to the legislature, “Mankind are all formed by the same Almighty Being, alike objects of his care,and equally designed for the enjoyment of happiness.” He argued that Congress had a duty to establish “the blessings of liberty…to all people living in the United States…without distinction of color.” Specifically citing enslaved Africans, Franklin urged that Congress grant “liberty to those unhappy men who alone in this land of freedom are degraded into perpetual bondage.” Congress balked and members from southern states harshly denounced Franklin, declaring slavery a God-given system.

The Philadelphian decried
what John C. Calhoun later labeled the “peculiar institution,” embodied in a 1780 slave sale in Charleston, South Carolina. (Rue Des Archives/Granger, NYC)

2. He invented bifocal spectacles. Writing in August 1784 to his friend George Whately, Franklin expressed great personal pleasure in the “invention of Double Spectacles, which, serving for distant objects as well as near ones, make my eyes as useful to me as ever they were.” Whately asked for more information. “The same convexity of glass through which a man sees clearest and best at the distance proper for reading is not the best for greater distances,” Franklin replied. “I therefore had formerly two pair of spectacles, which I shifted occasionally, as in traveling I sometimes read, and often wanted to regard the prospects. Finding this change troublesome, and not always sufficiently ready, I had the glasses cut and half of each kind associate 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 wanted to see distinctly far or near, the proper glasses being always ready.”

3. He made it easy to grab books. Franklin, a bibliophile, assembled one of the largest personal libraries in the colonies. To accommodate his books, he had to install shelves he could not reach. A born adapter, Franklin reconfigured a chair, adding hinged steps a user could swing into place and ascend as if on a ladder. Franklin sat in the chair while presiding over American Philosophical Society meetings in his library, leading acquaintances to call the piece of furniture “the president’s chair.” Another of Franklin’s book-related creations was the “long arm,” a board fitted with a cable that controlled two “fingers” at one end. A tug on the line caused the wooden appendages to close like a thumb and forefinger. Now largely absent from libraries, this device, in metallic form, sees use as a highway cleanup tool.

4. He grasped germ theory. Franklin was among the first to suggest that colds and flu spread not by cold air, as was thought at the time, but through “contagion” unrelated to temperature. “Traveling in our severe winters, I have often suffered cold sometimes to the extremity only short of freezing but this did not make me catch cold,” he wrote Philadelphia physician Benjamin Rush in 1773. “People often catch cold from one another when shut up together in close rooms, coaches, etc., and when sitting near and conversing so as to breathe in each other’s transpiration.” To avoid colds, he recommended getting as much fresh air as possible. All his life, Franklin ventilated his residences, especially his bedroom, even in winter. And at every opportunity he shed his clothes.

5. He described symptoms of lead poisoning. Franklin observed that roofers, plumbers, and other artisans working with the pliant metal often experienced joint paint, stiffness, and paralysis, as well as severe intestinal problems. Friends reported that the same symptoms appeared in drinkers of rum distilled using coils made of pewter, which has a high lead content. As a contemporary epidemiologist might have, Franklin diagnosed lead poisoning: “It affects among tradesmen those that use lead, however different their trades, as glazers, type-founders, plumbers, potters, white-lead makers and painters.” He urged caution in handling the substance and equipping stills with tin coils.

Franklin playing his armonicat. (From the Historical and Interpretive Collections of The Franklin Institute, Philadelphia, PA.)

6. He invented a musical instrument. At a 1761 concert in England, Franklin heard music made using only wineglasses holding different amounts of water. Within months he had fashioned what he called an “armonica”—37 glass bowls arranged by size on a spindle rigged with a foot pedal and spun by a flywheel. Once the armonica got going, simply touching the spinning rims with a wet finger produced notes. Writing to an Italian friend, Franklin described his instrument as “peculiarly adapted to Italian music, especially that of the soft and plaintive kind.” Europeans especially enjoyed the armonica. Mozart and Beethoven wrote music for the device; Marie Antoinette took armonica lessons.

7. He was a vegetarian—for a while. As a printer’s apprentice, the young Franklin read a book on vegetarianism’s benefits, and embraced the diet for health reasons—and to save money. Co-workers spent mealtimes in restaurants. Franklin read while eating biscuits and raisins, and felt better for it. “I made the greater progress from that greater clearness of head and quicker apprehension which usually attend temperance in eating and drinking,” he wrote. He drifted back into the carnivore ranks on a long sail. When the vessel’s crew caught and cooked a meal of cod, Franklin at first declined an invitation, but the aroma of fried fish proved too compelling. “I balanced some time between principle and inclination until I recollected that when the fish were opened, I saw smaller fish taken out of their stomachs,” he wrote. “‘Thus,’ thought I, ‘if you eat one another, I don’t see why we may not eat you.’  So I dined upon cod very heartily and have since continued to feast as other people, returning only now and then occasionally to a vegetable diet.”

8. He developed the fireplace insert. An open fireplace always has been a great way to heat cold air and send it up a chimney. Franklin made the fireplace more efficient by designing a wood-burning stove that enclosed the firebox. The device he called the “Pennsylvania fireplace,” and which quickly became known as the “Franklin stove,” needed less wood to make more heat and cut down on smoke and drafts. Thomas Jefferson bought one. Pennsylvania Deputy Governor George Thomas liked the device so much he said its inventor should patent it. Franklin declined: “As we enjoy great advantages from the invention of others, we should be glad of an opportunity to serve others by any invention of ours, and this we should do freely and generously.” 

9. He promoted exercise. In an era when life expectancy was 35 to 40 years, Franklin lived to 84, thanks to an exercise regimen emphasizing intensity. He realized a workout

A fanciful 19th century print imagines George Washington jumping rope to stay healthy in mimicry of Franklin. (The Granger Collection, New York)

needed to produce cleansing sweat that carries away toxins and recognized the importance of raising the heart rate. Walking a mile up and down stairs produced five times more body heat than walking a mile on the level, he noted. He calculated that when swinging weights that resembled today’s popular kettle bells his pulse rate went from 60 to 100 beats per minute.

10. He directed saboteurs and advocated reviving the use of an obsolete weapon. As the colonies were preparing to fight England, Franklin, as head of Pennsylvania’s defense committee, presided over development of secret underwater barriers for denying enemy warships use of the Delaware River. He fine-tuned gunpowder manufacturing and championed use in combat of the outdated but still deadly bow and arrow. “A man may shoot as truly with a bow as with a common musket,” Franklin wrote to General Charles Lee. “He can discharge four arrows in the same time of charging and discharging one bullet…A flight of arrows, seen coming upon them, terrifies and disturbs the enemies’ attention to their business…An arrow striking any part of a man puts him outside of combat till it is extracted.”