Heaviside, Oliver (1850-1925) was an English mathematical physicist. He correctly suggested that a layer of the upper atmosphere reflects radio waves. That layer is now called the Kennelly-Heaviside layer. Heaviside also helped develop the modern theory of telephone transmission.
Heaviside was born in London on May 18, 1850. As a child he contracted scarlet fever, which left him partially deaf. He was an excellent student, but his family could not afford to pay for his higher education. At age 16, he left school and began two years of self-guided study. The British physicist and inventor Charles Wheatstone was Heaviside’s uncle. In 1868, Wheatstone helped Heaviside secure a job at the new Danish-Norwegian-English Telegraph Company in Denmark.
During the mid-1800’s, the problem of telegraph signal distortions confounded telegraph engineers and scientists. For example, telegraph signals travelling from England to Denmark were significantly faster than those travelling from Denmark to England. Transmission quality also reduced over long periods of travel. These distortions were widely observed but their causes and solutions were largely a mystery. In the 1850s, the British physicist Lord Kelvin attempted to explain such distortions by comparing the movement of electricity to the flow of spreading heat. Kelvin’s theory sufficiently explained signal distortion in longer telegraph cables, but it did not apply to shorter cables.
Heaviside was keenly interested in using mathematics to solve the problem of telegraph signal distortion. In 1872, he published his first paper, on electromotive force , the amount of force needed to carry electricity through a circuit. He left the telegraph company in 1874 to research electromagnetism and telegraph transmission. Heaviside published a number of papers on the subject of telegraphy over the following years. He demonstrated mathematically that if electromotive force is distributed evenly along a telegraph line, then transmission distortion is reduced or removed altogether. The math that Heaviside used to demonstrate this principle became widely known among engineers as the telegrapher’s equations. These equations were key in the development of a transmission line theory.
In 1880, Heaviside received a patent for the invention of the coaxial cable, a type of cable that contains both an inner and an outer conductor. In the late 1880’s, he coined the terms inductance and conductance to describe the properties of an electric circuit. In 1902, Heaviside proposed that there must be a reflective layer of charged particles in the upper atmosphere that allows radio waves to travel long distances. He asserted this bold theory at about the same time as the American engineer Arthur Kennelly. Experiments in the 1920’s confirmed the existence of this atmospheric layer, which is now called the Kennelly-Heaviside layer (see Ionosphere ).
During his life, Heaviside was known as an eccentric. He kept his nails polished pink, and he often went to great lengths to avoid human contact. He signed his letters with the meaningless initials W.O.R.M. after his name, and called himself “the worm.” He died on Feb. 3, 1925. Heaviside’s work played an important role in the development of long-distance communication technology. His transmission line theory led to the eventual development of long-distance telephone lines.
