Margaret E. Knight was only 12 years old. Yet, like many children in 1850, she was already working in a cotton mill in Manchester, New Hampshire, spending her days in hot, dusty, crowded rooms filled with constant clatter from the looms. These machines ran fast, and when something failed, it often did so violently and sometimes tragically.
One day, as a loom wove cloth, a steel-tipped shuttle — the small carrier that held the thread — suddenly shot from the frame and struck a worker. Margaret saw the blood and pain and watched the panic that followed.
Most children would have walked away from the experience with a poignant memory of fear. Perhaps Margaret did as well. But she took something else away from the incident. She wanted to solve the problem that had taken place.
Margaret had always liked building things. Her sleds were admired by people in the neighborhood, and she often devised small tools and household improvements. So after the accident, she began working out a way to keep the shuttle from leaving the loom. Soon she devised a guard that prevented the shuttle from flying loose even if the threads snapped or the mechanism slipped. The change was simple enough to be fitted to existing looms.
The mill adopted her solution. Others followed, and injuries were reduced. She never patented the invention. But she had discovered that her love of building could solve others’ problems. A career unfolded.
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Margaret would build many contraptions throughout her long life. But the one that has impacted the world most and longest began in 1868, when she was working at a paper bag factory in Springfield, Massachusetts. The bags being manufactured were simple, folded pouches, glued along the sides with no flat bottom. When opened, they formed a loose sack that would not stand upright on a counter. These were the common bags of the day and a nuisance to grocery shopkeepers and shoppers alike.
Shopping at the time differed from what later generations would know. Customers did not browse aisles or select goods from shelves. Instead, they stood at the counter and placed their orders with the shopkeeper. Behind the owner were barrels and bins filled with flour, sugar, rice, coffee beans, and sometimes small hardware items, among other products. Nearly everything was sold loose, measured to order. Each product ordered would be placed in its own bag.
The existing bags made this difficult. Because they would not stand on their own, the clerk had to hold the mouth open with one hand while pouring with the other, all while watching the scale to see when the pointer reached balance. The paper shifted, folded inward, or tipped. If the bag collapsed, the contents spilled across the counter, and the weighing had to begin again. Clerks developed their own small tricks, including propping bags against jars or wedging them between their bodies and the scale. But these were workarounds, not solutions. The process worked, but it was slow and awkward.
Flat-bottomed bags that could stand upright and hold goods securely did exist. But they had to be folded by hand, which took time and skill, and no two looked quite the same. No machine could produce one reliably — the mechanics were too complex, the folds too precise.
Margaret believed a machine could, and set out to design one. She began designing a mechanism that would cut, fold, and glue paper into a bag with a square bottom, automatically forming the creases and tucked corners. In her boardinghouse, she constructed a wooden working model, adjusting gears and movements until the sequence operated correctly. When it performed reliably, she arranged for an iron version to be built at a machine shop.
That’s when Charles Annan walked into the story.
Annan worked at the machine shop and saw her design. He understood immediately what it could do, what it was worth. He had applied for a patent on a suspiciously similar machine.
Margaret contested the claim. The dispute became a patent interference case in the early 1870s. She was a woman with no formal education, no legal training, no powerful connections. And that’s how Annan presented it. His argument was that a woman could not have engineered a machine of such complexity. Therefore, he must have invented it.
Margaret arrived in court with her sketches, notes, and wooden model. Witnesses testified they had seen her developing the machine for months. She explained its mechanisms in detail, describing how each component functioned and why it was necessary.
The court ruled in her favor. Margaret E. Knight received U.S. Patent No. 116,842 for the flat-bottomed paper bag machine in 1871. She helped establish the Eastern Paper Bag Company, and the design went into mass production. The form she created became the standard paper bag used across the United States and eventually in much of the world.
She did not stop there.
Over her lifetime, she received at least twenty-seven patents, though some records suggest there were more. She designed machines for cutting shoe soles, improvements to rotary engines and automobile motors, window frames and sashes, dress shields, numbering mechanisms, sleeve valves. Most were modest improvements, the kind that rarely draw attention but make daily work easier, safer, and more efficient.
Margaret never married and lived modestly, investing much of her earnings back into experimentation and new designs. When she passed away in 1914, she had about $275 (about $9k today) to her name.
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Sources:
- Abrams, Michael. “Margaret Knight.” The American Society of Mechanical Engineers, https://www.asme.org/topics-resources/content/margaret-knight
- PETROSKI, HENRY. “The Evolution of the Grocery Bag.” The American Scholar, vol. 72, no. 4, 2003, pp. 99–111. JSTOR, http://www.jstor.org/stable/41221195. Accessed 20 Feb. 2026.
- Smith, Ryan P. “Meet the Female Inventor Behind Mass-Market Paper Bags.” Smithsonian Magazine, https://www.smithsonianmag.com/smithsonian-institution/meet-female-inventor-behind-mass-market-paper-bags-180968469/
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