The Day the Universe Changed - James Burke [139]
Faraday examined every potential conductor. He finally decided that the effect was caused by strain moving along lines of force in space itself and that an electric current was made up of the lines themselves acting in waves. His contemporaries thought little of the idea, since it appeared there was nothing in Newtonian space that would take the strain.
Meanwhile the public romance with science-which-was-technology intensified. Within ten years of Faraday’s discovery, small electric motors were being developed everywhere from the United States to Italy. There was even a crude form of electric locomotion. Principally, however, the public imagination was caught by Samuel Morse and his amazing telegraph. In 1844 a current was generated in Washington to switch on and off a small magnet in Baltimore which attracted and repelled a key. The key clicked, as the current switched on and off, in a code devised by Morse and named after him. The message was, ‘What hath God wrought?’
Operator transmitting by Morse telegraph. The speed of telegraphic communication had a huge impact on government and commerce. Armies came under centralised command, the arm of the law lengthened dramatically, and transactions on the stock market could be completed within hours.
The invention of the telegraph aroused a tumult of publicity. The public began to see science as the source of amazing novelties which would make life more exciting and comfortable for all. In fact the scientists were concerned more with solving the mystery of the electric force which threatened to destroy the very basis of the Newtonian view of nature. Those who agreed with Faraday that the force acted as part of space itself were few. In 1857 a Scotsman called James Clerk Maxwell wrote to Faraday:
You are the first person in whom the idea of bodies acting at a distance by throwing the surrounding medium into a state of constraint has arisen… your lines of force can weave a web across the sky and lead the stars in their courses without any necessary immediate connection with the objects of their attraction.
Maxwell’s initial approach to the mysterious lines of force was either deliberately traditionalist or meant to placate the conservative among his colleagues. In order to study the lines Maxwell conceived of them as tubes of varying diameter with an ‘ideal’liquid inside, carrying the energy, potential and work of the system. This concept would make the force amenable to hydrostatic measurement; the varying diameters would produce different liquid velocities which could represent different strengths of the force.
In an attempt to explain why the lines of force bunched up close to a magnet and then fanned out into space, Maxwell called on Descartes’old theory of vortices. However, whereas Descartes’vortices had spun, Maxwell made his tubes rotate. In order to prevent two adjacent rotating tubes from interacting he was forced to intersperse ‘idling’wheels, each one a molecule in size. The model was cumbersome, but it explained everything. The rotation of the vortices of the medium which filled space produced kinetic energy which was magnetic force. The transmission of the rotation created tangential pressures between one part of the field and another, which was electromagnetic force. The current was the movement of the liquid under the influence of the electromagnetic force. The resistance to all this activity produced heat.
With this model Maxwell solved the mystery of ‘action at a distance’by showing that there was no action happening at a distance.