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Benjamin Bradley was born a slave in Maryland, around 1830, but became an engineer and inventor. Although it was against the law to teach a slave how to read or write, Bradley learned literacy from his enslaver's children. Bradley was also good at mathematics, and showed a natural talent for making things. As a teenager, Bradley was put to work at an office where he built a working steam engine from pieces of scrap metal. Others were so impressed with Bradley's mechanical skills that he was given a job as an assistant in the science department at the United States Naval Academy in Annapolis, Maryland where he set up and helped conduct experiments. Professors at the Naval Academy were very impressed with Bradley, saying he was smart, a quick learner, and did not make mistakes. Bradley was paid in full for his work, but the money he had made went to his enslaver, who allowed Bradley to keep five dollars a month for himself. Bradley had not forgotten his work with steam engines. He saved the money he earned, and sold his original model engine to a student at the Academy. Bradley then used his savings to develop and build an engine large enough to run the first steam-powered warship. Because he was a slave, Bradley was not allowed to get a patent for the engine he developed. He was, however, able to sell the engine and keep the money, which he used to buy his freedom. He lived the rest of his life as a free man. Benjamin Bradley's name appears in few books, perhaps because he was not able to get a patent for his work. Just as there was disagreement over the issue of slavery, there was also disagreement over whether a slave should be allowed to hold a patent. Some people said anyone who came up with an original idea should be allowed to patent it. It should not matter whether that person was free or a slave. Others said that, because he, a slave, was his or her master's property, anything that a slave produced, including ideas, belonged to the master. In 1857, however, a slave owner named Oscar Stewart applied for a patent on something one of his slaves had invented. Stewart argued that he owned all the results of his slave's labor, whether that work had been manual. Despite the laws, the Patent Office agreed. The patent was granted, giving Stewart credit for the invention. The slave who actually came up with the idea (a cotton-processing device) is mentioned in the patent only as "Ned." Because of the decision in the Stewart case, the patent law was changed to say that a slave could not hold a patent. When the Confederate States broke away from the United States in 1861, the Confederate government surprised many people by once again allowing slaves to hold patents. After the Civil War, however, the patent law was changed again, specifying that all people throughout the United States had the right to patent their own inventions. Benjamin Bradley's cause of death was unknown. ==References== * * * 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Benjamin Bradley (inventor)」の詳細全文を読む スポンサード リンク
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