Radio Terms

Radio Record, Volume II, Issue 51, 5 July 1929, Page 13

Radio Terms

Their Origin Traced ALMOost everybody knows that the unit of electrical capacity by which the size of condensers is measured is known as a farad, writes R. P. Clarkson in the New York "Sun." I told one of my radio classes that this term is derived from the name Faraday, in honour of the great English electrician. One of the bright students immediately jumped to the conclusion that microfarad, by the same process, came from his full name, Michael Faraday ! The prefixes milli and micro are, of course, not peculiar to the electric art. They mean a thousandth and a millionth respectively, wherever you find them, just as kilo as a prefix always means thousand. A kilowatt is a thousand watts and a kilo-cycle is a thousand cycles. . The microfarad is, of course, the millionth part of a farad. Faraday is not the only brilliant scientist whose name has been made im-

mortal in the language of electricity. We have the volt in memory of Volta, the ohm in memory of a great Bavarian, G. S. Ohm, who, in 1826, established the law which bears his name. The ampere is likewise named in honour of Andre Marie Ampere, a great Frenchman. The unit by which we measure our inductance, the henry, perpetuates our own Joseph Henry, of Albany, N.Y., and later the first head of the Smithsonian Institution of Washington, D.C. In the lesser known units are the oersted, from the name of Hans Christian Oersted, a Dane, at one time professor at Copenhagen, and the first to show a relationship between the electrie current and magnetism. Then there is the coulomb, which measures the quantity of electricity and comes from C. S. Coulomb, who first experimentally verified the fact that ‘the forces of attraction and repulsion between two charges vary inversely as. the square of the distance between them, a choice bit of technical information. James Clark Maxwell, the great Scotch mathematician, provided his name in the maxwell or number of magnetic lines of force. Another Englishman, James Prescott Joule, who gave us the laws of conservation of energy and measured the relation between the various forms of energy, has given his name in the joule, which is the electrical unit of work done. And whenever we talk of watts or kilo-watts we are commemorating none other than James Watt, largely remembered for his work on the steam engine. Derived from the Greek. ost of the funny little names, such as electrodes, electrolyte, ion, anion, cathion, anode, cathode, electronic, paramagnetic, and many others came from Michael Faraday with the help of his (Continued on page 25.)

Origin of Radio Terms (Continued from page 13.) close companion, the Rev. W. Whewell, who apparently knew his Greek. The word electric was first used by Dr... William Gilbert, the physician to Queen Elizabeth, in the general sense we use it now, although the Greek word for amber is electron, and relates to the golden, sunlike colour of the stone which: played such an important part in the rise of electricity. The first work to use the word "electricity"? was written by Robert Boyle, and published at Oxford in 1675. Just where magnet comes from is hard to discover. There are many interesting tales, the most repeated being its derivation from a poem written by one Nicander, a couple of centuries B.C. It concerns a shepherd named Magnes, who, in. wandering around, found the ferrule of his staff suddenly adhering to a stone subsequently called after him the Magnes stone, or magnet. This is the first intimation that shepherds were accustomed to have their staves ferruled in the manner. of modern canes, and sounds rather fishy. Fully as interesting as any of our modern terms is the word "rheostat." This is the last survivor of a terminology which at one time was quite common. Hlectric meters, particularly galvanometers, which were about the only metres used, were called rheometres. The whole group of’ rheo words came from the fact that in Greek that word means "flow," and so galvanometres were "flowmetres" and varjiable resistances for keeping the flow steady became rheostats. The Personal Touch. Most of the early terms were derived from names of people, as the list above shows. Much descriptive language came from the same source. An electric battery was a "galvanic" cell, the name coming from poor old: Galvani, who certainly deserves something in his honour, and now we speak of galvanometres to commemorate this — great Italian.