Temistocle Calzecchi Onesti (14 December 1853 – 25 November 1922) was an Italian

physicist A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate cau ...

and inventor born in Lapedona,

Italy Italy, officially the Italian Republic, is a country in Southern Europe, Southern and Western Europe, Western Europe. It consists of Italian Peninsula, a peninsula that extends into the Mediterranean Sea, with the Alps on its northern land b ...

, where his father, Icilio Calzecchi, a medical doctor from nearby

Monterubbiano Monterubbiano is a town and ''comune'' in the Province of Fermo, in the Marche region of Italy. It is on a hill from the Adriatic Sea. History In pre-historic times the area was inhabited by the Piceni (9th-3rd centuries BC). After the Roman co ...

, was temporarily working at the time. His mother, Angela, was the last descendant of the ancient and noble Onesti family. His first name is the Italian version of the

Athenian Athens ( ) is the Capital city, capital and List of cities and towns in Greece, largest city of Greece. A significant coastal urban area in the Mediterranean, Athens is also the capital of the Attica (region), Attica region and is the southe ...

general

Themistocles Themistocles (; ; ) was an Athenian politician and general. He was one of a new breed of non-aristocratic politicians who rose to prominence in the early years of the Athenian democracy. As a politician, Themistocles was a populist, having th ...

. Calzecchi demonstrated in experiments in 1884 through 1886 that iron filings contained in an insulating tube will conduct an electric current under the action of an

electromagnetic wave In physics, electromagnetic radiation (EMR) is a self-propagating wave of the electromagnetic field that carries momentum and radiant energy through space. It encompasses a broad spectrum, classified by frequency or its inverse, wavelength, ...

. This discovery was the operating principle behind an early

radio wave Radio waves (formerly called Hertzian waves) are a type of electromagnetic radiation with the lowest frequencies and the longest wavelengths in the electromagnetic spectrum, typically with frequencies below 300 gigahertz (GHz) and wavelengths g ...

detector A sensor is often defined as a device that receives and responds to a signal or stimulus. The stimulus is the quantity, property, or condition that is sensed and converted into electrical signal. In the broadest definition, a sensor is a devi ...

device called the

coherer The coherer was a primitive form of radio signal detector used in the first radio receivers during the wireless telegraphy era at the beginning of the 20th century. Its use in radio was based on the 1890 findings of French physicist Édouard Bra ...

, developed about 6–10 years later by

Oliver Lodge Sir Oliver Joseph Lodge (12 June 1851 – 22 August 1940) was an English physicist whose investigations into electromagnetic radiation contributed to the development of Radio, radio communication. He identified electromagnetic radiation indepe ...

, Edouard Branly, and

Guglielmo Marconi Guglielmo Giovanni Maria Marconi, 1st Marquess of Marconi ( ; ; 25 April 1874 – 20 July 1937) was an Italian electrical engineer, inventor, and politician known for his creation of a practical radio wave-based Wireless telegraphy, wireless tel ...

, which was influential in the development of

radio Radio is the technology of communicating using radio waves. Radio waves are electromagnetic waves of frequency between 3 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmitter connec ...

Life and work

Monterubbiano was his home, where he spent his youth, studied, and spent other periods of his life, and died. Calzecchi graduated from the University of Pisa after studying the physical sciences and mathematics, then devoted himself to teaching in high schools and then scientific research. On 6 December 1879 he was appointed Professor of Physics at the Istituto tecnico at

L'Aquila L'Aquila ( ; ; ) is a city and ''comune'' in central Italy. It is the capital city of the Province of L'Aquila and the Abruzzo region in Italy. , it has a population of 69,902. Laid out within medieval walls on a hill in the wide valley of the A ...

. In 1883 he transferred to the Liceo Classico "A. Caro" in Fermo. In 1884 he began his studies of electrical resistance and conductivity of metal filings. In 1886, he founded a Physics Laboratory at the High School, including a meteorological observatory, at the expense of the City of Fermo and the Central Office of Meteorology and Geodynamics, organizing a weather information service for the region. In 1888 he moved to the Beccaria school in

Milan Milan ( , , ; ) is a city in northern Italy, regional capital of Lombardy, the largest city in Italy by urban area and the List of cities in Italy, second-most-populous city proper in Italy after Rome. The city proper has a population of nea ...

as a teacher of physics. In 1889 Calzecchi assisted the famous physicist

Galileo Ferraris Galileo Ferraris (31 October 1847 – 7 February 1897) was an Italian university professor, physicist and electrical engineer, one of the pioneers of AC power system and inventor of the induction motor although he never patented his work. Many ne ...

, testing the installation of electric lighting in Fermo. Meanwhile, the great physics discoveries of

Heinrich Hertz Heinrich Rudolf Hertz (; ; 22 February 1857 – 1 January 1894) was a German physicist who first conclusively proved the existence of the electromagnetic waves predicted by James Clerk Maxwell's equations of electromagnetism. Biography Heinri ...

Wilhelm Conrad Röntgen Wilhelm may refer to: People and fictional characters * William Charles John Pitcher, costume designer known professionally as "Wilhelm" * Wilhelm (name), a list of people and fictional characters with the given name or surname Other uses * Wilhe ...

, Nicola Tesla and

Augusto Righi Augusto Righi (; 27 August 1850 – 8 June 1920) was an Italian physicist who was one of the first scientists to produce microwaves. Biography Born in Bologna, Righi was educated in his home town, taught physics at Bologna Technical College bet ...

were made, including the transmission of telegraph signals without wires. Since 1884 Calzecchi had been researching the properties of metal powders, finding high electrical conductivity due to various excitations such as extra current, lightning, electrostatic induction, etc. Calzecchi's experiments with tubes of metal filings led to the development of the first radio wave detector, the

, in 1890 by Edouard Branly. This unit consists of a glass tube containing powder and nickel silver with traces of mercury, placed between two steel electrodes in vacuum. When it is hit by electromagnetic fields, the high resistance of the powder becomes relatively low until it is "percussed"—that is, hit, to break the welded bonds between the particles. These studies by Calzecchi predate by nearly six years those of the French physicist Edouard Branly and Oliver Lodge in England, although they are largely credited with the discovery. At the time, Calzecchi saw this as an invention for detecting lightning and as a seismic detector, but a lively debate followed when Branly, Lodge and Marconi used the coherer for radio.

References

* at radiomarconi.com
Onesti
at browsebiography.com {{DEFAULTSORT:Calzecchi Onesti History of radio technology 1853 births 1922 deaths 20th-century Italian physicists 19th-century Italian inventors 19th-century Italian physicists