'(<a href="http://www.j-archive.com/media/2006-11-06_J_28.jpg" target="_blank">Sarah of the Clue Crew indicates another drawing on the monitor.</a>) Edison writes: "A is a cylinder, having a helical indenting groove" in the 1877 patent application for this device'
a phonograph
EDISON'S PATENTS: Edison writes: A is a cylinder, having a helical indenting groove in the 1877 patent application for this device
Edison writes: "A is a cylinder, having a helical indenting groove" in the 1877 patent application for this device
Edison writes: "A is a cylinder, having a helical indenting groove" in the 1877 patent application for this device
EDISON'S PATENTS
a phonograph
EDISON'S PATENTS