What did Nikola Tesla do for the light bulb?
Tesla invented an alternating current power system
For the next two years, Edison’s DC electric generation spread the incandescent light to a growing number of cities across the country.
What did the black man invent?
The street letter drop mailbox with a hinged door that closed to protect the mail was invented by Philip B. Downing. Downing, an African-American inventor, patented his new device on October 27,1891 (US Patent # 462,096). The gas mask was invented by Garrett Morgan, an African-American inventor.
Why was Tesla lab burned?
“This is the last remaining Tesla laboratory anywhere in the world,” she said. … As with his previous Colorado Springs lab, assets were sold to pay down his debts. In 1917, the U.S. government blew up the tower, fearing that German spies were using it in World War I. The metal was sold for scrap, according to Alcorn.