George Washington signed the first patent law on April 10, 1790. Patents protect inventors. People who own a patent for an invention are the only ones who can make, use or sell that invention. Patents keep other people from stealing an inventor's ideas. They allow inventors to make a living from the things they create.

To get a patent, an invention must be new and do something useful. It can improve an already existing invention. Patents can be granted for machines, products and devices. Chemicals, food, drugs and the methods to make these things can also be patented.

In the past, not every inventor could ask for a patent. Before the Civil War, which lasted from 1861 to 1865, slavery was legal in the United States. Enslaved African-Americans were treated as property and couldn't apply for patents. This didn't stop them from creating new inventions, though. In 1721, Onesimus made a remedy for a terrible disease called smallpox. Papan, another enslaved person who lived in the 1700s, discovered a treatment for skin diseases. It worked so well that Virginia lawmakers freed him so that he could practice medicine.

There were many African-Americans, slave and free, who created and made inventions. Most of their stories have been lost to history. Three African-American inventors we know about are Benjamin Banneker, James Forten and George Peake. They all lived in the 1700s and they were all born free.

Benjamin Banneker

Benjamin Banneker was born in 1731. He taught himself math and became a mathematician. When he was 21, Banneker was shown a pocket watch. He was so fascinated by the watch that its owner lent it to him. Banneker studied watches and decided to build his own. A year later, he invented a clock out of wood that struck a gong every hour and kept time down to the second. Banneker's wooden clock kept time for more than 40 years.

In 1792, Banneker completed the first "Banneker's Almanac." Almanacs were books that told exactly when the sun came up in the morning and set at night. They also included other information, for example about eclipses and the moon. "Banneker's Almanac" was used by many people during the 1700s and 1800s.

Banneker gave a copy of his almanac to founding father Thomas Jefferson. He asked Jefferson to give black men and women equal rights and to fight against prejudice. But slavery did not end until 59 years after Banneker's death.

James Forten

James Forten, who lived from 1766 to 1842, was born in Philadelphia, Pennsylvania. He served in the U.S. Navy during the Revolutionary War. Captured by the British, Forten was offered his freedom if he agreed to live in England. Forten refused and said he never would become a traitor.

After the war, Forten became a sailmaker and created a device to handle ship sails. He patented his invention and became a wealthy man. Forten used his money to stand up for women's rights and end slavery.

George Peake

George Peake was born in 1722 and died in 1827. He also fought in the Revolutionary War. He was the first African-American in the town that eventually became Cleveland, Ohio.

Peake invented a hand mill for grinding corn. Compared to older methods, Peake's invention was easier to use and ground the corn more smoothly. Although Peake didn't patent his invention, a newspaper later gave him credit for it.