Editing Davy lamp (section)

== History ==
{{See also|Safety lamp#Timeline of the development of the safety lamp|label 1=Timeline of the development of the safety lamp}}
German polymath [[Alexander von Humboldt]], working for the German Bureau of Mines, had concerns for the health and welfare of the miners and invented a kind of respirator and "four lamps of different construction suitable for employment in various circumstances. The respirator was to prevent the inhaling of injurious gases, and to supply the miner with good air; the lamps were constructed to burn in the most inflammable kind of [[fire-damp]] without igniting the gas. They were the forerunners of Davy's later invention, and were frequently made use of by the miners."<ref>''Life of Alexander Von Humboldt, Vol. I'' (1872) Karl Bruhns (ed), Chapter III by Julius Lowenberg, p.152 in German. Translated to English in 1873 by Jane and Caroline Lassell.
[https://babel.hathitrust.org/cgi/pt?id=uc2.ark:/13960/t84j0d17j&view=1up&seq=13 in the public Domain via Library of Congress] Accessed 21 Dec 2021 {{LOC-general}}</ref>

Davy's invention was preceded by that of [[William Reid Clanny]], an Irish doctor at [[Bishopwearmouth]], who had read a paper to the [[Royal Society]] in May 1813. The more cumbersome Clanny safety lamp was successfully tested at Herrington Mill, and he won medals, from the [[Royal Society of Arts]].<ref name="Knight"/>

Despite his lack of scientific knowledge, engine-wright [[George Stephenson]] devised a lamp in which the air entered via tiny holes, through which the flames of the lamp could not pass. A month before Davy presented his design to the Royal Society, Stephenson demonstrated his own lamp to two witnesses by taking it down [[Killingworth#Killingworth Colliery|Killingworth Colliery]] and holding it in front of a fissure from which [[firedamp]] was issuing.<ref>{{Citation  | last = Brandling  | first = C J (chair)  | title = Report upon the claims of Mr. George Stephenson, relative to the invention of his safety lamp, by the committee appointed at a meeting holden in Newcastle on the First of November 1817  | url = https://books.google.com/books?id=AVYVAAAAQAAJ&pg=PA19  | year = 1817  | publisher = Emerson Charnley  | location =Newcastle  | page=17}}</ref>

The first trial of a Davy lamp with a wire sieve was at [[Hebburn]] Colliery on 9 January 1816.<ref name="Thompson2004"/> A letter from Davy (which he intended to be kept private) describing his findings and various suggestions for a safety lamp was made public at a meeting in Newcastle on 3 November 1815,<ref name="Paris1831">{{cite book|url=https://archive.org/details/lifeofsirhumphry02pari/page/88|title=The Life of Sir Humphry Davy, Late President of the Royal Society, Foreign Associate of the Royal Institute of France ...: In 2 volumes|last=Paris|first=John Ayrton|publisher=Colburn & Bentley|year=1831|volume=II|author-link=John Ayrton Paris}}</ref> and a paper describing the lamp was formally presented at a Royal Society meeting in London on 9 November.<ref name="Royal Society"/> For it, Davy was awarded the society's [[Rumford Medal]]. Davy's lamp differed from Stephenson's in that the flame was surrounded by a screen of gauze, whereas Stephenson's prototype lamp had a perforated plate contained in a glass cylinder (a design mentioned in Davy's Royal Society paper as an alternative to his preferred solution).<ref name="Royal Society"/> For his invention Davy was given £2,000 worth of silver (the money being raised by public subscription), whilst Stephenson was accused of stealing the idea from Davy, because the fully developed '[[Geordie lamp]]' had not been demonstrated by Stephenson until after Davy had presented his paper at the Royal Society, and (it was held) previous versions had not actually been safe.<ref name="Paris1831" /><ref name="Stephenson1817">{{cite book|url=https://books.google.com/books?id=SYkIAAAAQAAJ&pg=PA33|title=A description of the safety lamp, invented by George Stephenson, and now in use in Killingworth Colliery.|last=Stephenson|first=George|year=1817|edition=Second|location=London}}</ref>{{efn| The mean maximum quenching diameter (the maximum hole diameter through which a flame, but not an explosion, will not pass) for drilled holes in 1/32" thick brass plate  was reported in 1968 to be 0.139 inches for methane/air mixtures.<ref>{{cite journal|last1=Grove|first1=J R|title=The Measurement of Quenching Diameters and their Relation to the Flameproof Grouping of Gases and Vapours|journal=Third Symposium on Chemical Process Hazards with Special Reference to Plant Design LChem.E. Symposium Series|date=1968|volume=25|page=53|url=https://www.icheme.org/~/media/Documents/Subject%20Groups/Safety_Loss_Prevention/Hazards%20Archive/III/III-Paper-07.pdf|publisher=Institution of Chemical Engineers|location=London|access-date=30 April 2017|archive-url=https://web.archive.org/web/20171011071713/https://www.icheme.org/~/media/Documents/Subject%20Groups/Safety_Loss_Prevention/Hazards%20Archive/III/III-Paper-07.pdf|archive-date=11 October 2017|url-status=dead}}</ref> Davy's letter read at the 3 November meeting in Newcastle reported that his work on samples of firedamp had shown that ''explosions'' in flammable mixtures of firedamp with air would not pass through tubes of diameter less than 1/8".<ref name="Paris1831" />{{rp|84}} Stephenson's first lamp had a 1/2" air inlet, throttled by a slider, the second three air inlets of internal diameter 3/22" (0.136") but distorted by bending at the tip to give an oval, long diameter 1/5", short diameter 1/14", in his third lamp, air ingress was through brass plates with holes of various sizes, the largest about 1/12" diameter<ref name="Reportofctee1817"/>}}

A local committee of enquiry gathered in support of Stephenson exonerated him, showing that he had been working separately to create the Geordie lamp,<ref name="Reportofctee1817">{{cite book|url=https://books.google.com/books?id=AVYVAAAAQAAJ&pg=PA19|title=Report upon the claims of Mr. George Stephenson, relative to the invention of his safety lamp|author=Anon|publisher=S. Hodgson|year=1817|location=Newcastle}}</ref> and raised a subscription for him of £1,000.<ref name="Smiles1857"/>  Davy and his supporters refused to accept their findings, and would not see how an uneducated man such as Stephenson could come up with the solution he had: Stephenson himself freely admitted that he had arrived at a practical solution on the basis of an erroneous theory.<ref name="Smiles1857">{{cite book|url=https://archive.org/details/lifegeorgesteph03smilgoog|title=The Life of George Stephenson, Railway Engineer|last1=Smiles|first1=Samuel|publisher=John Murray|year=1857|location=London|pages=[https://archive.org/details/lifegeorgesteph03smilgoog/page/n122 95]–132|chapter=Chap. X.: Invents the "Geordy" Safety Lamp.|author-link=Samuel Smiles}}</ref>  In 1833, a [[British House of Commons|House of Commons]] committee found that Stephenson had equal claim to having invented the safety lamp.<ref name="Smiles1857"/>  Davy went to his grave claiming that Stephenson had stolen his idea.  The Stephenson lamp was used almost exclusively in [[North East England]], whereas the Davy lamp was used everywhere else.  The experience gave Stephenson a lifelong distrust of London-based, theoretical, scientific experts.<ref name="Davies">{{cite book|title=George Stephenson: The Remarkable Life of the Founder of the Railways|last=Davies|first=Hunter|publisher=Weidenfeld and Nicolson|year=1975|isbn=0-297-76934-0|author-link=Hunter Davies}}</ref>{{efn|In his book 'George and Robert Stephenson,' the author [[L.T.C. Rolt]] relates that opinion varied about the two lamps efficiency; that the Davy Lamp gave more light, but the Geordie Lamp was thought to be safer in a more gaseous atmosphere. He follows Smiles(1857) in referring to an incident in 1857 at Oaks Colliery in Barnsley where both lamps were in use. Following a sudden strong influx of gas the tops of all the Davy Lamps became red hot (which had in the past caused an explosion, and in so doing risked another), whilst all the Geordie Lamps simply went out.}}