View source for Rachet d'Everard (physicist)

{{About|the physicist Rachet d'Everard||Rachet d'Everard (disambugation)}}
{{Short description|Yonderian physicist}}
{{Infobox officeholder
|honorific_prefix   = Professor Doctor [[Barons of Yonderre|Baron]]
|name               = Rachet Hercule Peter d'Everard
|honorific_suffix   = [[Order of the Kestrel|OC]]
| image = Flinders_Petrie.jpg
| caption = d'Everard in 1903
| order = 
| birth_date = {{Birth date|1838|12|03|df=y}}
| birth_place = [[Sainte-Catherine]], [[Kubagne]], [[Yonderre]]
| death_date = {{Death date and age|1922|02|13|1838|12|03|df=y}}
| death_place = [[Sainte-Catherine]], [[Kubagne]], [[Yonderre]]
| resting_place = 
| spouse = {{marriage|Louise d'Everard (née d'Auguste)|1864}} 
| children = {{Plainlist|
* [[Phillipe d'Everard (paleontologist)]] (1865–1938)
* Michel d'Everard (1867–1869)
* Peter d'Everard (1869–1949)
* Rachette d'Everard (1871–1969)}}
| parents = {{Plainlist|
* Phillipe d'Everard (1810–1889)
* Sarah d'Everard (1816–1900}}
| relatives = ''See [[d'Everard (family)|d'Everard family]]''
| profession = Physicist
| nationality = [[Yonderre|Yonderian]]
| signature = PHE deverard signature ixwiki.png
| allegiance = {{flag|Yonderre}}
| branch = [[Yonderian Defence Force|Yonderian Army]]
| serviceyears = 1856–1858
}}

Professor Doctor [[Barons of Yonderre|Baron]] '''Rachet Hercule Peter d'Everard''' <small>[[Order of the Kestrel|OC]]</small> (December 3, 1838 – February 13, 1922) was a [[Yonderre|Yonderian]] physicist, chemist and [[Nobility in Yonderre|nobleman]] most notable for his discovered that electric currents create magnetic fields, which was the first connection found between electricity and magnetism. He also developed mathematical formulae to describe phenomena such as the relation between the refraction of light and the density of a pure transparent substance and the relation between a metal's electrical and thermal conductivity and temperature. A leader of the [[Yonderian Golden Age]], d'Everard made several discoveries in the field of physics and served as a professor at the [[University of Collinebourg]].

Rachet d'Everard was head of the [[House d'Everard]] from his father's death in 1889 until his own death in 1922. Rachet d'Everard was the father of world famous [[Paleontology in Yonderre|paleontologist]] [[Phillipe d'Everard (paleontologist)|Phillipe d'Everard]].

==Biography==
Rachet Hercule Peter d'Everard was born in the [[Bourg d'Everard]] December 3, 1838 to Phillipe d'Everard (1810–1889) and Sarah d'Everard (née Felz) (1816–1900). d'Everard was educated at the university-adjacent [[Collinebourg School of Excellency]] from the age of six where he took a liking to the sciences. Interrupted by a two-year conscription with the [[Yonderian Defence Force|Yonderian Army]], d'Everard attended the [[University of Collinebourg]] from 1858 and received a doctorate in 1864. d'Everard also married Louise d'Auguste (1843–1940) in 1864 and received a research grant from the [[University of Collinebourg]] the same year. 

In 1865, d'Everard discovered and subsequently published his discovery that a compass needle was deflected from magnetic north by a nearby electric current, confirming a direct relationship between electricity and magnetism. d'Everard made this discovery incidentally during a lecture, although he had, in fact, been looking for a connection between electricity and magnetism since 1862, but was quite confused by the results he was obtaining. For his discovery, the [[Grand Duke of Yonderre]] [[Giles IV Sentinelleau]] awarded d'Everard the [[Order of the Kestrel]] in 1866 and granted him 3,000 [[Yonderian Argent|Argents]] for further research.

d'Everard's findings stirred much research into electrodynamics throughout the scientific community, influencing [[Bergendii]] physicist Adrian Ampere's developments of a single mathematical formula to represent the magnetic forces between current-carrying conductors. d'Everard's work also represented a major step toward a unified concept of energy. The electromagnetic effect brought about a communications revolution due to its application to the improvement of the electric telegraph. The possibility of such a telegraph was suggested almost immediately by [[Urcea|Urcean]] mathematician [[Achaddeus Paulus]] and Ampere presented a paper based on Paulus' idea the same year as d'Everard's discovery. 

d'Everard's work with electromagnetism led him on to a career of working with electric lighting problems. He is credited with the invention in 1867–68 of a self-regulating arc lamp with an automatic movement of one electrode. He superintended the manufacture of the new lamp at the [[Beauregard Steel Works]] in the [[Spelph River Valley]], [[Stonne (Barony)|Stonne]]. On 28 November and 2 December 1868 d'Everard made displays with a lamp of 700 candlepower from the portico of the [[Bourg d'Everard]]. d'Everard investigated the mathematical description for light propagation through a single homogeneous medium and described the passage of light between different media. The formula for the mathematical relationship between the refractive index and the density of a medium was published by d'Everard in 1869, known as the d'Everard equation. Using his electromagnetic theory of light he stated what is known as the d'Everard gauge condition and was able to derive a correct value for the velocity of light. He also developed a theory of light scattering.

d'Everard spent most of his remaining academic career teaching physics at the [[University of Collinebourg]] where he made friends with other notable scientists of the period like [[Killian Lange]], [[Eberhard Sass]] and [[Thibault d'Avignon]]. His son [[Phillipe d'Everard (paleontologist)|Phillipe d'Everard]] would go on to study under d'Avignon and become world famous with his discovery and description of ''[[Caphirosaurus]]''.

Rachet d'Everard died February 13, 1922 and was buried in [[Sainte-Catherine]], [[Kubagne]].

==See also==
* [[Eberhard Sass]]
* [[Killian Lange]]
* [[Thibault d'Avignon]]
* [[Yonderian Golden Age]]
* [[House d'Everard]]

[[Category:House d'Everard]]
[[Category:Yonderre]]
[[Category:Yonderians]]
[[Category:Barons of Kubagne]]
[[category:Barons of Yonderre]]
[[Category:YDF Personnel]]
[[Category:People]]
[[Category:University of Collinebourg]]
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