The telegraph manual: a complete history and description of the semaphoric, electric and magnetic telegraphs of Europe, Asia, Africa, and America, ancient and modern.

742 UTILITY OF ELECTRIC TIME-BALLS.
the hour is sent from the observatory to different parts of the
country.
Correct longitudes have been taken simultaneously at Cambridge, Edinburg, and Brussels, by electric wires, communicating each with the other, and enabling the operators to communicate, as though assembled together. Greenwich, Brussels,
and Paris observatories are placed in connection, through the
submarine cabies running across the channel, from Dover to
Calais, and to Ostend.
elson's Monument and Time-Ball.