Monday, June 17, 2013

Sir Francis Ronalds

Sir Francis Ronalds was way ahead of Faraday. He had an intuitive grasp of induction that was decades ahead of his peers.  In 1823, Ronalds wrote "...the probability that the electrical induction which would take place in a wire enclosed in glass tubes of many miles in length might amount to the retention of a charge or at least might destroy the suddenness of the discharge."  He was the first to find that electrical signals were retarded when passing through an insulated wire, or run underground.

His name was still being invoked by engineers half a century later. He was possibly the first man of science to write about induction with any level of understanding. He knew that an electrical signal passed down a wire did not do so instantly, and that it was induction that slowed it's passage. In that same era Charles Wheatstone calculated the velocity of transmitted electrical signals. He was wrong. Wheatstone had not yet learned that the diameter of the wire effected the speed of the signal.

In 1816 Francis Ronalds erected two wooden frames to accommodate eight miles of iron wire for an experimental telegraph. This unit operated entirely on what the Journal of the Society of Telegraph Engineers called in 1870 "frictional electricity." Ronalds called it a "perpetual electrophorous."  It was in fact an electrostatic telegraph whose power was generated by synchronous revolving discs. By sending a current up the wire he was able to manipulate dry balls of pith  in a Canton pith ball electrometer. He also had a hot and hooked the ends up to pistols to set them off in perfect sync.

Since this predated Morse code, Ronalds had to improvise his own method of signalling. This was not quite as clever as his telegraph. He charged the wire and then grounded it at lengths indicated by a lettered dial matching a receiving dial at the other end. The dials excluded the letters J, Q, U, W, X and Z. It was inaccurate and slow. However he tested it at distances of up to 500 feet. This is amazing for an era when static electricity, galvanic electricity, dynamic electricity, and voltaic electricity were considered to be at least somewhat separate forces.

Ronalds lived long enough to see much of what he predicted to come true. he was knighted in 1870, three years before he died. While much of his work was original, in one of his pamphlets he gave credit to a number of now obscure figures: Hans Christian Oersted, Carl August Steinheil, Lord Cavendish, Tiberius Cavallo, William Watson and many others.