Sir Francis Ronalds's Telegraph

In 1816 Francis Ronalds invention of an electrostatic telegraph was built in his back garden. The IET Archives holds an extensive collection of Ronalds's papers and his rare book library.

Portriat of Sir Francis Ronalds


In 1816 Francis Ronalds, then living at Upper Mall, Hammersmith, built in his back garden two frames to accommodate eight miles of wire for his new invention of  an electrostatic telegraph based on synchronously revolving discs. For the past three or four years, encouraged by the octogenarian Swiss meteorologist, Jean Andre De Luc, Ronalds had been enthusiastically experimenting with electrostatic clockwork devices.  

After sending messages along his wires on the frame, he developed another version in which the wires were enclosed in glass tubes buried in the ground.  At each end of the line a clockwork mechanism turned synchronously revolving discs with letters on them.  A frictional electricity machine kept the wire continuously charged, while at each end two pith balls hung from the wire on silk threads, and since they were similarly charged from the wire they stayed apart.  

When someone desired to send a message he earthed the wire at his end at the moment when the dial indicated the desired letter. At the receiving end the pith balls would fall together when earthed and the recipient noted the letter showing on his dial at that moment.  The system was slow and depended on the two dials staying in step, but Ronalds demonstrated that it would work over 150 metres of wire.


A drawing of Sir Francis Ronalds's Garden Telegraph

With communications between London and Portsmouth in mind, Ronalds wrote to offer his invention to the Admiralty.   John Barrow, Secretary to the Admiralty, replied that "Telegraphs of any kind are now wholly unnecessary; and no other than the one now in use will be adopted."  (The one in use was a semaphore system.) Only a year after the end of the Napoleonic Wars, the Admiralty saw no need for improved communications, even though the semaphore was usable only in daylight and good weather.

In a small pamphlet published in 1823 Ronalds described his invention and listed some of its possible uses, "Why should not government govern at Portsmouth almost as promptly as in Downing Street?  Why should our defaulters escape by default of our foggy climate?  Let us have Electrical Conversazione offices communicating with each other all over the kingdom if we can."  Ronalds lived long enough to see his prophecies come to fruition and to receive belated official recognition: in 1870, three years before he died, he was knighted for his "early and remarkable labours in telegraphic investigations."