In Praise of Science and Technology by Carl Sagan

In the middle of the nineteenth century, the largely self-educated British physicist Michael Faraday was visited by his monarch, Queen Victoria. Among Faraday's many celebrated discoveries, some of obvious and immediate practical benefit, were more arcane findings in electricity and magnetism, then little more than laboratory curiosities. In the traditional dialogue between heads of state and heads of laboratories, the Queen asked Faraday of what use such studies were, to which he is said to have replied, "Madam, of what use is a baby?" Faraday had an idea that there might someday be something practical in electricity and magnetism.

In the same period the Scottish physicist James Clerk Maxwell set down four mathematical equations, based on the work of Faraday and his experimental predecessors, relating electrical charges and currents with electric and magnetic fields. The equations exhibited a curious lack of symmetry, and this bothered Maxwell. There was something unaesthetic about the equations as then known, and to improve the symmetry Maxwell proposed that one of the equations should have an additional term, which he called the displacement current. His argument was fundamentally intuitive; there was certainly no experimental evidence for such a current. Maxwell's proposal had astonishing consequences. The corrected Maxwell equations implied the existence of electromagnetic radiation, encompassing gamma rays, X-rays, ultraviolet light, visible light, infrared and radio. They stimulated Einstein to discover Special Relativity. Faraday and Maxwell's laboratory and theoretical work together have led, one century later, to a technical revolution on the planet Earth. Electric lights, telephones, phonographs, radio, television, refrigerated trains making fresh produce available far from the farm, cardiac pacemakers, hydroelectric power plants, automatic fire alarms and sprinkler systems, electric trolleys and subways, and the electronic computer are a few devices in