1895 – 1925 Early scientific discoveries and explorations that made radio possible.
1600: William Gilbert. First book about electricity and magnets.
William Gilbert was a pioneer of the experimental method and the first to explain the magnetic compass. In 1600, Gilbert published his great study of magnetism. De Magnete – the first ever book about experimental physics, and arguably the first ever scientific text – opened the era of modern physics and astronomy and started a century marked by the great achievements of Galileo, Kepler, Newton and others. He was also the first person to use the terms "electric force," "magnetic pole," and "electric attraction". Gilbert was also court physician to Queen Elizabeth I of England, and briefly to James VI/I.
An early observation of the relationship between magnetism and electric current.
The Effect of a Thunder Clap on the Compass of a Ship
Philosophical Transactions of the Royal Society, v14 1684 pages 520-521
1732 December 6: Lightning Magnetizes Cutlery
An early observation of the relationship between magnetism and electric current
An Account of an Extraordinary Effect of Lightning in communicating Magnetism
Philosophical Transactions of the Royal Society, v39 1735-36 pages 74-75
1746 January: Pieter van Musschenbroek. Discovery of the Leyden jar (electrical capacitor)
We can classify all electrical technology into either DC (direct current) and AC (alternating current). AC technology is by far more widely used than DC. All AC technology — including electric power systems and radio – depends on capacitance as one of its fundamental components (along with resistance and inductive reactance).
1748-49 February 22 (4 March 1749 N.S.): Lightning Destroys the Polarity of a Mariners Compass
An early observation of the relationship between magnetism and electric current.
A Letter...concerning the Effects of Lightning in destroying the Polarity of a Mariner's Compass; To Which Are Subjoined Some Remarks Thereon
Philosophical Transactions of the Royal Society, v46 1749-50 pages 111-117
1757 November 9: William Mountaine and James Dodson. That great magnet, the Earth
Observations concerning the Magnetic Needle.
(pages 333-334):— We conclude that the magnetic needle "is influenced by various and different magnetic attractions, in all probability occasioned by the heterogeneous compositions in the great magnet, the Earth."
1777 January: William Henly. Comment on the future of electricity
We now (1777) know a lot, but there's still much more to be discovered ... I think we may safely conclude, that electricity, as it is one of the most powerful, is also one of the most important, agents in nature. Many useful discoveries have been made …. compared with the facts still undiscovered …..they bear but a very small proportion.
Philosophical Transactions of the Royal Society v67 Dec 1777, pages 97-98
1781: Luigi Galvani. The electric effect of different metals
Luigi Galvani's work with frogs led to his discovery in 1781 of galvanic or voltaic electricity. An important step in the scientific investigation of electricity. His name is recalled by a word in modern English, galvanized, used to describe someone stirred to sudden, abrupt action.
1785: Charles Augustin de Coulomb. Coulomb's Law of Electrostatic Force
In the 1770s, Charles Augustin de Coulomb invented the torsion balance that can measure small forces such as those produced by electrostatic charges. He developed a clear description of the forces generated between two electrostatic charges that we now know as Coulomb's Law.
1800: Count Alessandro Giuseppe Antonio Anastasio Volta. The first battery to supply electric current.
In 1800, after six years of experimenting, Volta assembled a device that was able to produce a large continuous flow of electricity. Volta's breakthrough invention suddenly made it possible for people to have a reliable and predictable supply of significant electric current. It is no accident that many important electrical discoveries came in the next few decades including telegraph systems. In 1809 Von Soemmering demonstrated a working electric telegraph and in 1835 William Cooke saw the electric telegraph built by Professor Muncke at Heidelberg; on returning to England, Cooke worked with Wheatstone to develop an electric telegraph good enough to be put into regular use in May 1838. All of these telegraph systems, and all commercial telegraph lines throughout the rest of the 1800s and well into the 1900s, were powered by batteries.
1809: Von Soemmering's electric telegraph
A physician, anatomist, anthropologist, paleontologist and inventor, Sommering was one of the most important German anatomists. In 1809 von Soemmering demonstrated the first electric telegraph, able to send messages over a distance at a rate of about two letters a minute. This was a genuine electric telegraph that could deliver messages reliably over a distance that was limited only by the length of wire available.
1820: Hans Christian Oersted. Observation of magnetic effect of an electric current
Before 1820, the only magnetism known was that of iron magnets and of lodestones (natural magnets). He demonstrated the connection between electricity and magnetism. We now use the words “electromagnetic” and “electromagnetism” to refer to the combined effects of magnetism and electricity.
The Electromagnetic Revolution: Oersted's discovery
A Ridiculously Brief History of Electricity and Magnetism
1825: William Sturgeon. First electromagnet
In 1825 he demonstrated his invention, the first electromagnet – capable of lifting twenty times its own weight,
displaying its strength by lifting nine pounds [4kg] with a seven-ounce [200g] horseshoe-shaped bar of iron wrapped with about eighteen turns of wire, connected to a one-cell (low voltage) battery.
1826: Andre Marie Ampere. Mathematical analysis of magnetic effect of electric current
Ampere is generally credited as one of the main discoverers of electromagnetism. The SI unit of measurement of electric current, the ampere, is named after him. Ampere is best known for his demonstration that electric currents produce magnetic fields, and his subsequent investigation into the relationship between these two phenomena.
1827: Georg Simon Ohm. Publication of Ohm's Law
What is now known as Ohm's Law first appears in a book printed in Berlin in 1827: Die galvanische Kette, mathematisch bearbeitet (The Galvanic Circuit Investigated Mathematically). He discovered that, in a particular material arranged in a particular form – an iron wire, or a copper bar, or a lead cylinder, etc. – the electric current in the circuit is directly proportional to the number of cells in the battery. This is what is now known as Ohm's Law, one of the most fundamental principles of electricity.
1831: Michael Faraday. Discovery of electromagnetic induction
In 1831, Michael Faraday began his great series of experiments in which he discovered electromagnetic induction, the ability of a changing magnetic field to produce a voltage in a nearby conductor. The important term is "changing". Any time a conductor (wire loop) is in the influence of a magnetic field that varies in strength, an electric current is set up in the conductor. It is this effect, that we now call "electromagnetic induction," that is the basis of present-day generation of electric power, the transmission of information using the electromagnetic spectrum (radio, television, radar, microwave, etc.) and many other useful applications of electricity.
1829-1832 Faraday and Henry
Michael Faraday in England, and Joseph Henry in New Jersey, were experimenting at the same time, 1829-1832, with electric circuits and the associated magnetic effects. Both were working without knowing that the other was doing similar work. Henry's experiments that revealed electromagnetic induction were done mostly in August 1830, a few months before Faraday, but Faraday published first and thus is given primary credit for this discovery.
1831: Joseph Henry. Discovery of electromagnetic self-inductance
In 1830, Joseph Henry began experimenting with insulated wires wound an iron core, and succeeded in making powerful electromagnets. These magnets were powered by an electric current from a battery made according to Volta's design. In 1830-1831, he deduced the property known as self-inductance, the inertial characteristic of an electric circuit.
1864: James Clerk Maxwell. Mathematical prediction of electromagnetic waves
In 1864, Scottish mathematician James Clerk Maxwell described electromagnetism – the relationship between electricity and magnetism – in four classic equations. Collectively known as Maxwell's equations, they describe the interrelationship between electric fields, magnetic fields, electric charge, and electric current. Some of the solutions to these equations indicated that there were such things as electric waves. At the time, in the 1860s and 1870s, the notion of electric waves seemed incomprehensible, but their existence was proved experimentally in 1888 by Heinrich Hertz, and in the mid-1890s practical applications began to appear through work by Popov, Marconi, Fessenden, Poulsen and others.
1884: Temistocle Calzecchi Onesti.
Onesti made the so-called "filings tube" that, many years later, was given the name "coherer", a glass tube filled with metal filings which acts as an insulator when placed in a circuit with a low-voltage battery. This serves as a way to detect the presence of electromagnetic radiation. These studies by Onesti predate by nearly six years those of Edouard Branly in France and Oliver Lodge in England, although they are largely credited with the discovery.
The Possibility of Wireless Becomes Reality
1884 October 11: Communication between Ships at Sea. Telegraphing across the ocean without a cable
At the meeting of the American Association for the Advancement of Science, Professor A. Graham Bell, the inventor of the telephone, read a paper giving a possible method of communication between ships at sea by use of a dynamo and his telephone system. Professor Trowbridge also offered a method.
1888: Heinrich Hertz. Proof of the existence of electromagnetic radiation (radio waves)
In the decade 1880-1890, the most important advance in electrical physics was that which originated with the research of Heinrich Rudolf Hertz, an experimental realization of a suggestion made by G.F. Fitzgerald in 1883 as a method of producing electric waves in space. He discovered the progressive propagation of electromagnetic action through space, and measured the length and speed of these electromagnetic waves. He also showed that like light waves they were reflected and refracted. Hertz also noted that electrical conductors reflect the waves and that they can be focused by concave reflectors. He found that non-conductors allow most of the waves to pass through. These waves, originally called Hertzian waves but now known as radio waves, conclusively confirmed Maxwell's prediction of the existence of electromagnetic waves, both in the form of light and radio waves. Today, the term "hertz" (short form "Hz") is used as the unit of frequency for an electromagnetic oscillation or wave.
1890: Edouard Branly. Invents a way to detect electromagnetic waves
The first practical instrument for detecting Hertzian waves. The instant an electric discharge – a spark or an arc – occurred in the vicinity the coherer's metallic filings became conductive, and then if it was tapped lightly its conductivity vanished and it became an insulator. When connected in a low-voltage circuit, in its ordinary state a coherer had a resistance of millions of ohms, but this dropped dramatically to hundreds of ohms when electromagnetic waves were produced in the vicinity. The coherer was a very useful device in the early days of experimentation with electromagnetic waves. It was widely used from the early 1890s until about 1910, when what we now call vacuum tube rectifiers became available.
Branley's invention was a big step forward in the development of the science and technology of electromagnetic radiation. Today we all are immersed continuously in a wash of electromagnetic radiation. We are surrounded by electromagnetic radiation coming from all directions, yet – without suitable instruments – we are wholly unaware of it because humans do not have the sensory ability to detect this radiation. Today we have an amazing variety of cheap everyday devices that are able to detect the presence of electromagnetic radiation, from ordinary radio receivers, mobile phones to GPS receivers, etc. Before Branley's invention of the coherer, the only way to detect the existence of electromagnetic radiation was the primitive arrangement used by Heinrich Hertz. But whenever we are temporarily without one of these devices, we are unaware of the sea of electromagnetic radiation that exists from the surface of the Earth upward through the atmosphere and outward millions of kilometres into space.
1891: Fred Trouton suggests rotating alternator for wireless transmitter
Trouton noted that if an electrical alternator could somehow be run fast enough, it would generate electromagnetic radiation. This approach was later explored by Fessenden and Alexanderson.
1895 May 7: Alexander Stepanovich Popov. Early radio receiver
In the early 1890s, Alexander Popov was working in Russia on a way to detect thunderstorms by using atmospheric radio waves to detect the occurrence of distant lightning strokes. Anyone who has listened to an AM radio receiver while a thunderstorm is active, can understand how a radio receiver works as a lightning detector. In 1894 he built an apparatus that could register electrical disturbances due to lightning, and then suggested that it could be used for receiving man-made signals. It contained a coherer. Without question, this was a primitive radio receiver. In 1896, he demonstrated the transmission of radio wave signals between different parts of the University of St. Petersburg.
1895: Marconi's early wireless experiments in Switzerland
In February 2003 it was acknowledged Marconi's early wireless experiments in Salvan, Switzerland, were a "Historical Milestone". Recalling that Salvan had been the theatre of a major event in the history of electrical engineering and of mankind. Through his intelligence and doggedness of purpose, Marconi, father of wireless communications, provided an example of creativity and inventiveness to younger generations.
1896 June 2: British Patent number 12039
Guglielmo Marconi is awarded British Patent number 12039, the world's first patent for a system of telegraphy using Hertzian waves (radio).
1897 January 29: Bose lectures on electromagnetic radiation
In this 1897 lecture, Bose demonstrated his devices for the generation and detection of radio waves. More than five hundred people including Oliver Lodge, James John Thomson and Lord Kelvin had assembled to hear Bose. The lecture was not only praised but it was considered valuable enough for publication in the Transactions of the Royal Society. The University of London conferred on him the D.Sc. degree for his work on electric waves.
The date of Bose's "Friday Evening Discourse" has been reported in some sources as Friday 19th January 1897, or as Friday 19th July 1897. The problem is, in the year 1897, January 19th was a Tuesday, and July 19th was a Monday. However, the 1897 calendar shows January 29th as a Friday.
Jagadish Chandra Bose
1897: Braun Invents the Cathode Ray Tube Oscillograph
Braun’s invention the first cathode ray tube (CRT) is an essential tool for working with radio waves. Beginning in the 1920s and to the present day, millions of CRT devices have been manufactured and sold, for oscilloscopes, television receivers, computer monitors, hospital electronic and monitoring devices, etc. In 1909, Braun was awarded the Nobel Prize jointly with Guglielmo Marconi. Braun had produced four improvements in wireless circuitry that were recognized by the committee awarding the Nobel Prize; it was also noted that Braun's replacement for the Marconi spark-gap circuit was not simply an improvement but an important new advance.
In December 1914, Braun travelled to New York to testify in a patent suit involving the large German wireless telegraph station at Sayville, Long Island, New York – after the two German submarine (underwater) telegraph cables had been cut in August 1914 (see below), the Sayville wireless station was the most important remaining communications link between Germany and the United States at a time of heightened international tension – against legal (patent) attacks by the British controlled Marconi Corporation. When the United States entered World War One, in April 1917, Braun was interned as an enemy alien and died before the war ended.
1897 July 20: The Wireless Telegraph and Signal Company
In 1897, with the help of wealthy relatives, Marconi founded the Wireless Telegraph and Signal Company, with Colonel Jameson Davis, a cousin, as the first Managing Director. The company was registered (incorporated) on 20 July 1897. On 24 March 1900, the name was changed to Marconi Wireless Telegraph Company Limited.
1898 July 20: Kingstown Regatta Reported by Wireless
One of the biggest scoops in Irish newspaper history involved the Kingstown Regatta in the summer of 1898. The results of the yacht races were not especially interesting, but the technology used to transmit them was revolutionary. Guglielmo Marconi, the Italian inventor of wireless telegraphy, was commissioned by T.P. Gill, editor of the Dublin Daily Express newspaper, to report the results of the races "direct from the high seas". The newspaper chartered a yacht, The Huntstress, for Marconi, who set up his equipment and a mast on board. He followed the regatta 10 miles out into Dublin Bay, to Kish Lighthouse, and, on July 20th, 1898, sent back the first-ever press report by wireless telegraphy to a land station in the harbourmaster's office. This report was printed on a Morse tape machine, decoded and telegraphed to the newspaper's newsdesk.
Marconi had strong Irish connections. His mother, Annie Jameson was a member of the whiskey-distilling family of Daphne Castle, County Wexford, and his first wife was Beatrice O'Brien, daughter of Edward Donough O'Brien, the 14th Baron Inchiquin of County Clare.
Marconi (left) with his assistant George Kemp
Kingstown Regatta Experiments: Newspaper report by wireless telegraphy column from the Dublin Daily Express describing the second day (July 21) of reporting on the yacht races at Kingstown Regatta