Margaret Knight, Inventor of the Paper Grocery Bag (and 87 other Inventions)

In her time, she was called "the most famous woman inventor,” but today, chances are, you’ve never even heard of Margaret Eloise Knight. It’s unfortunate, because If you do any grocery shopping, you have her to thank for making it so much easier. Her invention created a product that is as unassuming as it is ubiquitous.

A self-taught engineer, Margaret Knight invented the machine to produce flat-bottomed paper bags, and then founded the Eastern Paper Bag Company in 1870, creating paper bags for groceries very similar to the ones used today.

During her lifetime, as a woman-inventor during the late 19th and early 20th Centuries, she overcame a surprising amount of adversity to achieve both her goals and the recognition she deserved—at a time when few women held intellectual property. Here is her story…

Early Years and Early Inventions

Margaret E. Knight was born in York, Maine on February 14, 1838 to Hannah Teal and James Knight. After her father died, “Mattie,” as her parents nicknamed her, moved to Manchester, New Hampshire and was raised by her widowed mother.

Any formal education she had was limited to secondary school but like many people during the industrial era, she left school with her siblings to work at a riverside cotton mill in Manchester to support her widowed mother.

In an unregulated, dangerous factory setting, the preteen toiled for paltry wages from before dawn until after dusk.

That did not stop her from creating a clever device at a young age. As a little girl, Knight preferred to play with woodworking tools instead of dolls, stating that “the only things [she] wanted were a jack knife, a gimlet, and pieces of wood.” Her friends were amused and even slightly horrified, her deep interest in tools—but she was also famous for her kites, and her sleds were the envy of the boys in town.

At the age of 12, Knight witnessed an accident at the mill where a worker was stabbed by a steel-tipped shuttle that shot out of a mechanical loom (manipulated by workers to unite the perpendicular weft and warp threads in their weaves) at high velocity with the slightest employee error. It was one of the leading causes of grievous injury at the mill.

The mechanically minded Knight set out to fix this. Within weeks, she invented a safety device for the loom that was later adopted by other Manchester mills. While the exact nature of it is unknown, it may have been either a device to stop the loom when the shuttle thread broke or a guard to physically block a flying shuttle.

She then decided to create a device that restrained shuttles from falling out of the looms by turning off the entire machine when something went wrong. It was of the first innovations to touch a range of industries.

At the time, she had no notion of patenting her idea.

It was well known that Knight had not received credit for her work as a young teenager when she was still working at the cotton mill and that she was not allowed to patent her very own design.

Health problems precluded Knight from continuing to work at the cotton mill. In her teens and early 20s she held several jobs, ranging from home repairs, upholstery, to daguerreotype and ambrotype photography.

The Flat-Bottomed Paper Bag

As the years went by and she generated more and more such concepts, Knight came to see the moneymaking potential in her creativity.

As an adult after the civil war, she went to work at the Columbia Burlap Bag Company located in Springfield, Massachusetts. There, she noticed that the envelope-shaped bags were narrow, weak, and, lacked a sturdy base to facilitate packing. She recognized that flat square-bottomed shaped bags were more practical and sturdy—and yet, at the time, they were considered artisanal items, and were not at all easy to come by in common life.

The more useful and sturdy flat-bottomed paper bags needed to be made by hand. Her idea was to mechanize the process of flat-bottom bag making.

Knight developed a proposal for mechanizing the production of flat-bottomed paper bags, that were poorly made by an existing device.

In 1868, Knight studied the existing bag-making machine to figure out how a machine might be altered to accomplish the task. She eventually put together a wooden model she could use to test her plan. She saw that it worked but knew that to apply for a patent, she needed a working model made of iron. She took the project to a machine shop in Boston and explained what she wanted them to build.

Once complete, she applied for her patent.

The Patent Fight

This was considered a bold move for a woman in the 19th century, a time when a vanishingly small percentage of patents were held by women (even allowing for those women who filed under male aliases or with sex-neutral initials).

Soon, she discovered that one of her machine shop coworkers, Charles Annan, had stolen her design and patented the device himself.

In response, Knight filed an unprecedented patent interference lawsuit against Annon. In response to his bigoted argument that no woman could be capable of designing such a machine, Knight presented her original, meticulously detailed hand-drawn blueprints, and even presented diary entries that proved how long she had worked on this machine. Annan, who had no such evidence to offer himself, was quickly found to be a fraud.

She fought for months, spending hundreds of dollars to secure what rightfully hers. Finally, in 1871, she was awarded the patent at the age of 32.

Knight was not the first person to come up with the idea of a flat-bottomed bag. They were already in general use in England, having been produced by hand since at least the 1840s, and improvements to hand-production techniques occurred during the 1850s: for example, a patent was awarded to James Baldwin of Birmingham in 1853 for semi-mechanized apparatus to use in the making of flat-bottomed paper bags.

Knight acquired two more patents later on as she made improvements to her “industrial origami” bag-making device that allowed the machine to work more efficiently and allow mass production of paper, fly-bottomed bags—vastly increasing the speed, quality, and consistency of their production.

Knight’s idea promised to democratize the user-friendly bags, ushering out the cumbersome paper cones in which groceries were formerly carried and ushering in a new era of shopping and transport convenience.

Knight successfully patented many of her very inventions, however it wasn't done with ease or without obstacles.

Democratizing the Paper Bag

She founded the Eastern Paper Bag Company in Hartford, Connecticut. with a Massachusetts business partner, and received royalties.

There, Knight encountered some resistance to her as a woman, but as she proved her complete understanding of manufacturing and the machinery, she won the workers’s respect.

Legacy of Leadership, Perseverance and Innovation

Even though she overcame many barriers in the life of women in the 1800's and was deemed 'successful', she was never able to profit from her inventions due to her gender. Another reason Knight was dismissed so often was because she wasn't a wealthy or highly educated woman.

She is quoted as saying,

“I’m only sorry I couldn’t have had as good a chance as a boy,”

yet she was able to overcome many of the challenges and limits facing women inventors during her lifetime.

Knight never married, and lived until the age of 76 in Framingham, Massachusetts. She never stopped coming up with new ways to solve problems. She rented space on High Street in Boston where she could run her experiments. She spent many long hours there.

Though she was in her sixties when automobiles were coming into their own, she was fascinated by them. She patented a series of improvements to the rotary engine. between 1902 and 1915. Her gasoline-powered engine was known as the Knight Silent Motor. She also developed “non-skiddable” tires.

Most of her patents had to do with various ways to improve manufacturing. One was a machine for boring holes, another was for a numbering machine, lid removing pliers, a numbering machine, a window frame and sash, patented in 1894.

In the mid-1890s she also dedicated herself to creating a better machine for making shoes.

The implications of Knight’s eventful life were addressed in widely read ink as early as 1913 (one year before her death), when the New York Times, in what was then a refreshingly progressive move, ran a lengthy feature on “Women Who Are Inventors,” with Knight as the headliner. Explicitly rebutting the lingering notion that women weren’t wired for innovation (“The time has come now. . . when men must look to their laurels, for the modern field is full of women inventors.”), the author of the article called special attention to Knight (“who at the age of seventy is working twenty hours a day on her eighty-ninth invention”).

Knight was described as “woman Edison” in an obituary when she died on October 12, 1914.

Though she managed to live more comfortably in middle and old age than in childhood, Knight was never rich by any means. She died alone with her achievements, and a mere $300 to her name.

A plaque recognizing her as the "first woman awarded a U.S. patent" and holder of 87 U.S. patents hangs on the Curry Cottage at 287 Hollis St in Framingham. (However, Knight was not actually the first: either Mary Kies or Hannah Slater also have that honor).

Knight was inducted into the National Inventors Hall of Fame in 2006. A scaled-down but fully functional patent model of her original bag-making machine is in the Smithsonian Museum in Washington, D.C.

No doubt many female inventors of the early 1900s—and later—were inspired by Knight’s courageous example to better the world around them. But, as a post-script to this narrative, it’s also worth noting that even in contemporary America, where women have full property rights and hold many more positions of power in government than in the 1800s, fewer than 10 percent of “primary inventor” patent awardees are female—an unquestionable result of longstanding discouraging norms.

So today, when you’re at the grocery store and you choose paper over plastic, that’s a good time to thank Margaret Knight.