The key to Edison's fortunes was telegraphy. With knowledge gained from years of working as a telegraph operator, he learned the basics of electricity. This allowed him to make his early fortune with the stock ticker, the first electricity-based broadcast system. Edison patented the sound recording and reproducing phonograph in 1878. Edison was also granted a patent for the motion picture camera or "Kinetograph". He did the electromechanical design, while his employee W.K.L. Dickson, a photographer, worked on the photographic and optical development. Much of the credit for the invention belongs to Dickson.[48] In 1891, Thomas Edison built a Kinetoscope, or peep-hole viewer. This device was installed in penny arcades, where people could watch short, simple films. The kinetograph and kinetoscope were both first publicly exhibited May 20, 1891.
