When it comes to late 19th- and early 20th-century technological innovations, no individual had a greater impact than Thomas Alva Edison, the Wizard of Menlo Park. For example, Edison invented the world’s first machine to record and reproduce sound in 1877. He called his invention a phonograph. In 1878, he patented the device and made about 500 machines before turning his attention to the light bulb. That work would lead to the formation of a...Continue Reading