A system of conveying intelligence to a distance by means of signals produced by aid of the electric current. The two stations, which may be several thousand miles apart, are connected by a wire along which the electricity flows. The electric current, produced by a galvanic battery, passes along the wire with immense velocity, and is capable of acting upon an electro-magnet at great distances. In the common Morse system the sender uses a small instrument, by tapping which with his finger he can break off tbe current at will. When this is done quickly the receiving instrument gives a quick sound, or makes a dot on paper. When slowly, there is a longer sound, or a dash on paper. These dots and dashes are variously combined to represent the letters of the alphabet. These are now caught by the ear, paper not being used. Telegraph lines are usually carried through the air on wooden poles, galvanized iron being used. Telegraphs also pass under the oceans, their wires being surrounded by insulating material , the whole being called a cable. Telegraphing without wires has recently been invented.

GROVE'S CELL.

GROVE'S CELL.