Heaviside was like Sir Isaac Newton in that he worked alone and did not always publish the whole of his experiments. He wrote a lot of ideas in his notebooks, but he did not think these ideas were ready for publication, yet they turned out to be very important. For example, he suggested that there was an atmospheric conducting layer many kilometers above the earth’s surface which could be used for sending long-distance radio-waves around the curvature of the earth. In 1923 it was indeed discovered that there were complex, ionized layers (called the ‘‘ionosphere”). The Kennelly-Heaviside layer was later named after him. By 1950, 25 years after his death, there were more than 50 stations worldwide experimenting with radio communication in the upper atmosphere.