Built by Black Hands:
The Inventors America Erased

Thomas Jennings was a free Black tailor in New York City who, in 1821, became the first African American to receive a United States patent — for a dry-cleaning process he called "dry scouring." At the time, most Black people in America were legally property, barred from owning anything, including their inventions. Jennings was a rare exception: a free man in New York operating a successful tailoring business.

The patent law of the time excluded enslaved people from filing patents because they couldn't enter into legal contracts — the government explicitly acknowledged the contradiction and allowed it to stand for nearly 40 more years. Jennings used the income from his dry-scouring business to purchase the freedom of his wife and children from slavery. His daughter, Elizabeth Jennings Graham, would later be at the center of a landmark civil rights case in 1854 — she was forcibly removed from a New York City streetcar, sued the transit company, and won, establishing the desegregation of New York public transit a full century before Rosa Parks.

Norbert Rillieux was a free Creole man born in New Orleans, educated as an engineer in Paris, and responsible for one of the most economically significant industrial inventions of the 19th century — the multiple-effect evaporator, which revolutionized sugar refining. Before Rillieux's invention, refining sugar was an extremely dangerous and inefficient process that required enslaved workers to ladle boiling cane juice between open kettles. His vacuum-evaporation system replaced this with a closed, steam-heated process that was simultaneously safer, faster, and 80% cheaper.

The invention was adopted across Louisiana sugar plantations, then Cuba, Mexico, and Europe. Charles A. Brown, the Smithsonian's chief food technologist, later called it "the greatest invention in the history of American chemical engineering." Yet Rillieux returned to France in 1854, driven out by Louisiana's tightening Black Code laws that restricted the movement of free people of color. He spent his later decades in Paris, where he published Egyptological research and died in relative obscurity.

Elijah McCoy was born in Canada to parents who had escaped slavery via the Underground Railroad. He trained as a mechanical engineer in Scotland, returned to the United States after the Civil War, and could find only one job: oiling locomotive engines by hand for the Michigan Central Railroad. It was beneath his qualification. He used the time to solve the problem himself.

Steam locomotives of the 1870s had to stop completely every few miles so workers could manually lubricate the moving parts. McCoy invented an automatic lubricating cup that distributed oil continuously while the engine ran. The device worked so well that rail companies across the country adopted it — and competitors began making imitation devices that didn't work as reliably. Railroad engineers started specifically requesting McCoy's version, reportedly asking for "the real McCoy." The phrase entered the language. Elijah McCoy's name did not make it into standard history books for another hundred years.

Jan Ernst Matzeliger emigrated from Suriname to Massachusetts and found work in a shoe factory in Lynn — at the time the shoe capital of the world. The most difficult part of shoemaking was "lasting": attaching the leather upper to the sole by hand. Skilled lasters earned high wages and were considered irreplaceable. Matzeliger, working alone in his boarding room with almost no resources, spent five years building a machine that could last a shoe automatically. Patent examiners sent an agent to his workshop in disbelief. The agent confirmed it worked.

His 1883 patent transformed the American shoe industry. Production doubled, then tripled. Shoe prices dropped by half, putting shoes within reach of working-class Americans for the first time. The company that bought his patent — United Shoe Machinery Company — became one of the largest corporations in the United States. Matzeliger received $15,000 in shares. He died of tuberculosis in 1889 at age 37, having never collected the full value of his invention.

Granville Woods was a self-taught engineer who became one of the most prolific inventors in American history — holding over 60 patents in electrical engineering, railway systems, and telecommunications. His most important invention, the "Induction Telegraph" (1887), allowed moving trains to communicate with stations and with each other using electromagnetic induction. Before this invention, train conductors had no way to know if another train was on the same track ahead of them. The Induction Telegraph directly reduced rail collisions.

Thomas Edison challenged Woods in court twice, claiming prior invention. Woods won both cases. Edison then offered to bring Woods into the Edison Company as a partner; Woods declined. He sold patents individually to General Electric, Westinghouse, and the American Bell Telephone Company — each time receiving a fraction of what the patents earned those companies. He invented the third rail system used by electric railways and subways, a version of which still powers the New York City subway. He died in 1910 in New York City, penniless.

Lewis Howard Latimer was born to parents who had escaped slavery from Virginia. He taught himself drafting by sneaking looks at books in the Boston law office where he worked as an office boy. By the time he was an adult, he was among the finest draftsmen in the country — he drafted the patent drawings for Alexander Graham Bell's telephone application in 1876. But his most significant contribution came in electrical engineering.

Thomas Edison's original light bulb used a carbonized paper filament that burned out within hours. Latimer invented a carbon filament made from a cotton thread process that lasted significantly longer, patented in 1882. Without a practical filament, electric lighting was a laboratory curiosity, not a commercial product. Latimer's invention made the light bulb viable for widespread use. He supervised the installation of electric light systems in New York, Philadelphia, Montreal, and London, and later joined Edison's company — where he was the only Black member of the elite "Edison Pioneers."

Sarah Boone was born into slavery in Craven County, North Carolina. She was freed after the Civil War, moved to New Haven, Connecticut, and became a dressmaker. In 1892, she became one of the first Black women to hold a United States patent — for an improved design of the ironing board.

Before Boone's innovation, ironing boards were flat, wide planks that made it difficult to iron the curved sleeves and the narrow bodies of women's dresses without wrinkling them further. Boone's design narrowed and curved the board to follow the shape of a sleeve, and made it reversible so both sides of a garment could be pressed smoothly. The adjustable, narrowed ironing board that every home in America uses today descends directly from Sarah Boone's 1892 patent. Her name is not on it.

Garrett Morgan was a self-taught inventor who solved two of the most deadly problems of his era: gas exposure and traffic collisions. In 1914, he patented the "safety hood" — a device that filtered toxic fumes so that a wearer could breathe in smoke-filled spaces. In 1916, an explosion trapped 32 workers deep inside a tunnel under Lake Erie in Cleveland. Morgan put on his own device and personally led rescue teams into the tunnel, saving all 32 workers. The story made national news — until newspapers discovered he was Black. Several papers rewrote the story to credit white rescuers.

Morgan sold the safety hood patent to the U.S. Army, which used it as the basis for gas masks in World War I. He then invented a three-position traffic signal in 1923 — adding an intermediate "warning" position between stop and go — the foundational design of every traffic light in the world. He sold that patent to General Electric for $40,000. The modern traffic light generates hundreds of billions of dollars in economic activity. Morgan received $40,000 and eventually went blind.

Sarah Breedlove — known as Madam C.J. Walker — was born in 1867 on a Louisiana cotton plantation to parents who had just been freed. Both parents died when she was seven. She was married at 14, widowed at 20, and a laundress in St. Louis earning $1.50 a day. By 1919, she was the first self-made female millionaire in American history — of any race.

Walker developed a line of hair care products specifically for Black women, using a heated metal comb she designed and a proprietary formula she developed after suffering from scalp disease caused by harsh chemicals. She built a distribution network of 40,000 Black women sales agents across the United States — creating an economic infrastructure during Jim Crow that gave Black women an income independent of white employers. Her Indianapolis headquarters employed hundreds. She lobbied President Woodrow Wilson personally to make lynching a federal crime. He refused. She donated to the NAACP anyway.

Charles Drew was a physician and medical researcher who developed the first large-scale blood bank and the techniques for processing and preserving blood plasma that are still in use today. As the United States entered World War II, Drew was appointed director of the first major American Red Cross blood bank — the "Blood for Britain" project — which collected plasma for Allied troops. He then designed and ran the U.S. Army and Navy blood bank programs.

In 1941, the American Red Cross ordered that blood donations from Black and white donors be labeled and stored separately, so that white soldiers would not receive blood from Black donors. Drew — the man who invented the blood bank — resigned in protest. The science was clear: there is no racial difference in blood. The policy was pure Jim Crow, applied to battlefield medicine. The policy remained in effect until 1950. Drew died in 1950 in a car accident in North Carolina; some accounts suggest he was refused treatment at a white hospital, though this is disputed.

Alice Ball was 23 years old when she developed the first effective treatment for leprosy (Hansen's disease) — an injectable extract of chaulmoogra oil that, for the first time, allowed patients to be released from isolation hospitals and live normal lives. She was the first Black person and the first woman to earn a Master's degree from the University of Hawaii. She died in 1916 at age 24.

The University of Hawaii's president Arthur Dean then published her research under his own name, calling it the "Dean Method." Dean used the treatment for years without crediting Ball. It was not until 1922 that a colleague, Dr. Harry Hollmann, published a paper acknowledging that Ball had developed the technique. The University of Hawaii did not officially honor her until 2000 — 84 years after her death. The state of Hawaii declared February 29 "Alice Ball Day" in 2000.

Percy Julian was one of the most important chemists of the 20th century. A grandson of Alabama slaves, he became the first Black person to earn a Ph.D. in chemistry from the University of Vienna in 1931. He synthesized physostigmine from the calabar bean — ending the threat of blindness from glaucoma for millions of people. He then synthesized progesterone and testosterone from soy sterols, which eventually led to the development of synthetic cortisone. Before Julian's process, cortisone cost $200 per drop. His synthesis from soybean oil made it affordable for mass use, transforming treatment for arthritis and immune disorders.

In 1950, Percy Julian moved his family into a house in Oak Park, Illinois — a white suburb of Chicago. Two weeks later, his home was bombed. The following year, someone attempted to burn it down while his children slept inside. No one was ever arrested. He held 130 patents, was named one of the greatest chemists in American history by the American Chemical Society, and spent a significant portion of his life defending his family from violent white neighbors.

Katherine Johnson was a mathematician who joined NASA's predecessor, NACA, in 1953 — assigned to the pool of Black women "computers" who performed calculations by hand. She quickly distinguished herself as exceptional. When NASA began using electronic computers in the early 1960s, astronaut John Glenn insisted that Johnson personally verify the computer's orbital calculations before he would board Friendship 7. If she said the numbers were right, he would fly.

Johnson calculated the trajectory for the first American crewed spaceflight (Alan Shepard, 1961), John Glenn's orbital mission (1962), the Apollo 11 Moon landing (1969), and the emergency return trajectory for Apollo 13 (1970). She worked at NASA for 33 years and was critical to the success of every major American space mission of the 20th century. Her work was classified for decades. She was not publicly credited by NASA until the 2015 release of the book (and subsequent film) Hidden Figures. She received the Presidential Medal of Freedom in 2015. She was 97 years old.

Lonnie Johnson earned a degree in mechanical engineering from Tuskegee University, worked as a nuclear engineer in the U.S. Air Force, and then joined NASA's Jet Propulsion Laboratory, where he worked on the Galileo mission to Jupiter and the Mars Observer project. In his home laboratory in 1982, while experimenting with an environmentally friendly heat pump that used water instead of freon, he accidentally shot a stream of water across his bathroom and thought: that would make a great water gun.

The Super Soaker became one of the best-selling toys in American history, generating over $1 billion in sales. Johnson licensed it to Hasbro — and then spent years in litigation after Hasbro underpaid his royalties. A jury awarded him $73 million in 2013. He used the proceeds to fund Johnson Research and Development, which is working on a next-generation battery (the Johnson Thermo-Electrochemical Converter) that could potentially triple the energy density of current lithium-ion batteries.

Mark Dean co-invented the ISA bus — the Industry Standard Architecture system that allowed peripheral devices like printers, monitors, and keyboards to communicate with a computer's processor. Without the ISA bus, there is no personal computer as we know it. He holds three of the nine original patents on the IBM PC. He also led the team that developed the first 1 gigahertz computer chip in 1999, breaking a milestone that had been considered years away.

Dean became the first Black IBM Fellow — the company's highest technical honor — in 1996. He later became a computer science professor at the University of Tennessee. He noted in a 2011 essay that he had moved on from personal computers to tablets: "When I helped design the PC, I didn't think I'd live long enough to witness its decline." His name is almost never included in popular histories of the personal computer revolution.

Patricia Bath grew up in Harlem and was mentored as a teenager by the same Percy Julian mentioned in this thread. She became an ophthalmologist and, in 1981, co-founded the American Institute for the Prevention of Blindness — based on the principle that "eyesight is a basic human right." She observed that Black Americans suffered far higher rates of blindness than white Americans — not from any biological cause, but from lack of access to eye care. She spent her career closing that gap.

In 1988, she patented the Laserphaco Probe — a device using laser technology to remove cataracts more precisely and with less trauma than the mechanical tools then in use. The invention allowed patients who had been blind for over 30 years to have their sight restored. Bath was the first Black female physician to receive a medical patent in the United States. Her device is used in surgeries worldwide.

James West grew up in Virginia and was warned by his family not to pursue science — it wasn't considered a viable career for a Black man. He ignored the advice, attended Temple University, and joined Bell Laboratories in 1957. In 1964, he and colleague Gerhard Sessler co-invented the foil electret microphone — a small, lightweight, inexpensive condenser microphone that could be mass-produced for almost nothing.

The foil electret microphone is now in virtually every device in the world that records or transmits sound. It is in your smartphone, your laptop, your baby monitor, your hearing aid, your car's hands-free system, and your smoke detector. 90% of the more than one billion microphones manufactured each year use West's design. West holds over 250 patents and is a member of the National Inventors Hall of Fame. He continues to work on acoustic technology at Johns Hopkins University.

Shirley Ann Jackson became the first Black woman to earn a doctorate from MIT in 1973 — at a time when she was one of fewer than twenty Black students at the institution, and the only Black woman in the physics program. She conducted research in theoretical physics at Bell Laboratories that contributed directly to the development of the touch-tone telephone, portable fax machines, caller ID, call waiting, solar cells, and fiber optic cables.

Jackson's research on the properties of electrons at surfaces and interfaces — semiconductor physics — laid the groundwork for the telecommunications infrastructure of the modern world. She later became chair of the U.S. Nuclear Regulatory Commission under President Clinton and is currently president of Rensselaer Polytechnic Institute. Bill Clinton described her as "perhaps the ultimate role model for women in science." Her name is rarely included in standard accounts of the telecommunications revolution.

Jerry Lawson was a self-taught engineer who joined Fairchild Semiconductor in the 1970s as one of the only Black engineers in Silicon Valley. Before Lawson, video game consoles were fixed-hardware machines — you bought the console, and the games were hardwired in. You couldn't change them. Lawson designed the Fairchild Channel F in 1976: the first home video game console with a removable, interchangeable cartridge. Each cartridge was a self-contained program the machine could read and run.

Atari, Nintendo, Sega, and every other console maker that followed adopted the cartridge architecture. The $200+ billion video game industry runs on the concept that Lawson invented. He was the chief hardware engineer at Fairchild and received no royalties from the cartridge format he created. He left the company and founded his own game studio — one of the first Black-owned video game companies in America. He died in 2011. Google honored him with a Doodle in 2022.

Marian Croak holds over 200 patents and is the engineer most responsible for Voice over Internet Protocol (VoIP) — the technology that allows voice and video calls to travel over the internet rather than traditional phone lines. Working at AT&T Bell Labs, she developed the technical foundations for transmitting voice data in digital packets, solving the latency and quality problems that had made early internet voice calls unreliable.

Every call you make on Zoom, FaceTime, WhatsApp, Google Meet, or Skype runs on the architecture that Marian Croak built. The shift from circuit-switched to packet-switched voice communication is one of the most consequential changes in the history of human communication — it moved billions of phone calls from physical infrastructure to software, collapsing the cost to near zero. Croak currently leads responsible AI development at Google. She was inducted into the National Inventors Hall of Fame in 2022 — one of the few inventors in this thread to be recognized while still alive.