Only 20% of patents granted in the United States belong to women. But behind the invention of some revolutionary technologies that we use today are these female inventors, who in most cases went unnoticed in a world in which it was mostly men who achieved visibility. We rediscover their stories and vindicate their creations, without which our lives would be very different.
New Yorker Amanda Jones (1835-1914) developed the Jones process to preserve food in 1872. She devised a method of vacuum canning that was improved with successive patents, until fruits, vegetables or meats could be stored for much longer than usual. Her ideas ranged from sterilization before packaging to dehydration of the products, while always keeping the food in an environment devoid of atmosphere, which prevented the proliferation of microorganisms that degrade food.
Before becoming an inventor, Jones wrote poems and stories that she published in six books. In an attempt to change her life, she founded the Chicago-based Women’s Canning and Preserving Company. As a great defender of women’s rights, all the shareholders of her company were female, as were all the employees. But her business venture eventually failed and she had to emigrate to Kansas with two of her sisters. There she continued working on perfecting her inventions until her death due to flu.
American Mary Anderson (1862–1954) was a versatile woman who dedicated herself to real estate development and viticulture, although she will be remembered for being the inventor of the windshield wiper. The inspiration arrived one snowy day during a streetcar ride through New York City. The entrepreneur noticed that the driver had to get out every so often to clean off the windshield. On her way back to her native Alabama, she decided to create a device that would clean it automatically, and ended up manufacturing one with the help of a local company.
In 1903 Anderson got her first patent, which was for 17 years, for a machine that cleaned the front window of the car and could be controlled from inside the vehicle using a lever: in essence it was already a device similar to modern windshield wipers. Two years later, in 1905, she tried to sell her invention to a Canadian firm, which refused to buy it. In 1922, when Anderson’s patent had already expired, Cadillacs became the first cars to adopt the windshield wiper as standard equipment.
Melitta coffee machines are named after Melitta Bentz (1873–1950), the German woman who developed the drip brew paper coffee filter in 1908. As a good housewife, Bentz observed that the strainers of the time did not filter the coffee very well and left grounds in the drink. Determined to find an alternative, she experimented with different types of filters until she tried blotting paper —which she obtained from the exercise book of one of her children— on a perforated plate. In this way she managed to make coffee without impurities that was very successful, which encouraged her to set up a business based on her invention.
After a halt in the production of her filters during the First World War, by 1929 the demand for her product had reached 100,000 units. With the outbreak of the Second World War, manufacturing stopped again, before resuming in 1948. At the time of Bentz’s death, her company was worth almost five million German marks (just over $9 million today).
The first woman to be awarded a Ph.D. in Physics from the University of Cambridge, American Katharine Burr Blodgett (1898–1979), obtained eight patents throughout her life, the most prominent of which was anti-reflective glass, which she developed while working at General Electric. Normal glass reflects a significant portion of light, but Blodgett discovered that by using very thin layers of a type of liquid soap as a coating, 99% of the light would pass through. She patented her method in 1938 under the name of Film Structure and Method of Preparation, which for a long time was the only way to achieve transparent glass. Her invention is currently used in eyeglasses, cameras, telescopes, windshields, computers and television screens.
Before her invention, at the age of just 21 and with the First World War in full swing, she defended her thesis on the chemical structure of gas masks. Blodgett determined that carbon molecules could absorb almost all the poisonous gases of the chemical weapons of the moment, which helped to improve the masks during the Second World War. Her work saved many lives.
While working for the DuPont chemical company, American Stephanie Kwolek (1923–2014) discovered Kevlar (poly-paraphenylene terephthalamide, by its scientific name), a yellow fibre five times stronger than steel. Kwolek was looking for hard, lightweight materials for the manufacture of tires, so the first use of this fibre was to make wheels. Today it has more than 200 applications, the main one being the production of bulletproof vests for security forces around the world. It can also be found in underwater cables, helmets, aerospace products and automobile brakes.
Kevlar was not the only material that Kwolek worked with; throughout her life she obtained 17 patents. Her work earned her the Lavoisier Medal and entry into the National Inventors Hall of Fame, being the fourth woman to do so. After forty years at DuPont, Kwolek retired in 1986 but continued working to bring science closer to young people, especially girls.
American typist Bette Nesmith Graham (1924-1980) invented the first correction fluid in 1956, which at the beginning she called Mistake Out. She sought to effectively eliminate the mistakes she herself made at her workplace, where electric typewriters had begun to be used. So she developed a type of white tempera paint that covered them up, and on which she could type over. She mixed the first batch of the liquid in her own kitchen, and then distributed it to her co-workers in bottles displayed with the name of the product.
Two years later, in 1958, Graham founded the Mistake Out Company and continued to work from home in the evenings and at weekends to generate the product. Shortly thereafter, she shortened the name of her invention to Liquid Paper and offered it to IBM, which declined the offer to acquire it. Finally, in 1979, the Gillette Corporation bought Graham’s invention for almost $50 million (almost $190 million today). These days, 25 million bottles of Liquid Paper are manufactured each year.