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 nickna...

On This Day, April 9, 1940, the patent for the first shopping cart is granted to its inventor Sylvan Goldman, the owner of a Humpty Dumpty Grocery store in Oklahoma City. It was essentially a folding chair with wheels and baskets attached. The carts were initially a flop, as shoppers were reluctant to use them--men found them effeminate and women thought them too much like a baby carriage - so he hired models to shop with them.

Eventually, folding carts became very popular and Goldman became a multimillionaire by collecting a royalty on every folding design shopping cart in the United States.

By any measure, Goldman was an innovator. In addition to his invention of the shopping cart, early in his career as a grocer he developed many of the advertising and marketing techniques now commonly used by supermarkets.

He once said his idea for the shopping cart came from watching women carrying baskets. ''They had a tendency to stop shopping when the baskets became too full or too heavy,'...