9781422277669

Thomas Edison became very adept at sending messages on the Morse key, as this transmitter was called.

Words to Understand

duplex— a telegraph circuit that can transmit two messages at once. electromagnet— iron or steel magnetized by an electric current passing through a coil of wire surrounding it. filibuster— unnecessarily long speech delivered to hold up business in an assembly. Morse code— dot-and-dash system of representing the letters of the alphabet. Devised for telegraphists by U.S. inventor Samuel Morse (1791–1872). patent— the exclusive right to make, use, or sell an invention for a given number of years. telegraph— device for sending messages to a distant point by making and breaking an electric circuit in a connecting wire.