‘Unification’ shows the underlying connection between electricity and magnetism was discovered by James Clerk Maxwell. His electromagnetism theory describes the behaviour of electric and magnetic fields and how they relate to charges and currents. Maxwell found that the speed of the electromagnetic wave was equal to the speed of light and was the first to understand that a beam of light consists of electric and magnetic oscillations propagating together. This discovery was far-reaching. Though the speed of the waves is fixed, the wavelength can take any value. Many 19th-century phenomena — X-rays that provided pictures of the skeleton, radio waves that transmitted messages, and infrared radiation — were all examples of electromagnetic radiation.