Editing Burning glass (section)

==Use==
=== War: since the legend of Archimedes ===
The first story akin to that of burning glass is by Archimedes, for the purpose of war, in 212 BC. When Syracuse was besieged by Marcus Claudius Marcellus, the Roman fleet was supposedly incinerated by the use of not glass per se, but a concave mirror made of brass focusing sunlight. Whether or not that actually happened, eventually the city was taken and Archimedes was slain.<ref>Meijer, Fik (1986), A History of Seafaring in the Classical World, Routledge, {{ISBN|978-0-7099-3565-0}}</ref>

In 1796, during the [[French Revolution]] and three years after the declaration of war between France and Great Britain, physicist [[Étienne-Gaspard Robert]] met with the French government and proposed the use of mirrors to burn the invading ships of the British [[Royal Navy]].  They decided not to take up his proposal.<ref name="PreCinema">Burns, Paul.  "[http://www.precinemahistory.net/1750.htm The History of The Discovery of Cinematography: Chapter Six, 1750–1799]".  Accessed 29 July 2007.</ref>

=== Domestic use: primitive fire making ===
[[File:Flat_flexible_plastic_sheet_lens.JPG|thumb|240x240px|Close-up view of a flat [[Fresnel lens]]. This thin, lightweight, non-fragile and low-cost lens can be used as burning-glass in emergency situations.]]
[[File:Leaf being burned with telescope.jpg|thumb|222x222px|A makeshift burning glass, using the eyepiece of a [[telescope]], being used to burn a leaf.]]
Burning glasses (often called '''fire lenses''') are still used to light fires in outdoor and primitive settings.<ref>{{cite web|url=http://www.primitivefire.com/Fire-Glass_c_1.html |title=Fire Glass |publisher=Primitivefire.com |access-date=2012-12-18}}</ref> Large burning lenses sometimes take the form of [[Fresnel lens]]es, similar to [[lighthouse]] lenses,<ref>
{{cite journal
 | journal = Proceedings of the Engineers' Society of Western Pennsylvania
 | title = Light House Lenses
 | author = George A. Macbeth
 | year = 1914
 | page = 245
 | volume = 30
 | url = https://books.google.com/books?id=rFTOAAAAMAAJ&q=fresnel%20%22burning%20glass%22&pg=RA1-PA245
 }}</ref> including those for use in [[solar furnace]]s.<ref>
{{cite book
 | title = Solar Energy: Fundamentals and Applications
 | author = H. P. Garg, J. Prakash
 | publisher = Tata McGraw-Hill Education
 | year = 2000
 | isbn = 9780074636312
 | page = 305
 | url = https://books.google.com/books?id=-v_LfcIdJxIC&q=lens+solar+furnace&pg=PA305
 }}</ref> Solar furnaces are used in industry to produce extremely high temperatures without the need for fuel or large supplies of electricity. They sometimes employ a large [[Parabolic reflector|parabolic]] array of mirrors (some facilities are several stories high) to focus light to a high intensity.

=== Religion: sacred fire ===
In various religions settings, a burning glass is used to set off some sort of [[Fire worship|sacred fire]].

From the 7th to the 16th centuries, a burning glass was used by Christians to set off the [[Easter Fire]] during the [[Easter vigil]]. Thus, [[Saint Boniface]] explained to [[Pope Zachary]] that he produced the new fire of Holy Saturday by means of a crystal lens concentrating the rays of the sun. This process was also mentioned in liturgical books until the [[Roman Pontifical]] of 1561.<ref>{{Cite web|last=de Villiers|first=Henri|date=30 March 2021|title=La réforme de la Semaine Sainte de 1955 – 7ème partie – La Vigile pascale|url=https://schola-sainte-cecile.com/2021/03/31/la-reforme-de-la-semaine-sainte-de-1955-7eme-partie-la-vigile-pascale/|access-date=2021-04-26|website=Schola Sainte-Cécile Official website|language=fr-FR}}</ref>

In [[Cambodia]], a burning glass has also been used since ancient times for the [[cremation]] of kings and most recently for the funeral of [[King Sihanouk]]. The crematorium of the king is traditionally prepared by the [[Baku (brahmin)|Bakus brahmin]] from the [[Royal Palace of Cambodia|Royal Palace]] on the last day of the week-long funeral. Small pieces of fragrant [[agarwood]] are placed beneath the magnifying glass until it ignites. The incandescent wood is used to light candles and pass on the fire to the attendees, who usually take their lit candles home.<ref>{{Cite web|title=The King and Queen Mother offer fire to His Majesty the King|url=https://www.rfa.org/khmer/indepth/late-ex-king-cremation-02042013072246.html|url-status=live|access-date=2021-04-26|website=Radio Free Asia|language=en|archive-url=https://web.archive.org/web/20210426143845/https://www.rfa.org/khmer/indepth/late-ex-king-cremation-02042013072246.html |archive-date=2021-04-26 }}</ref>

=== Sports: lighting the Olympic torch ===
The [[Olympic torch]] that is carried around the host country of the [[Olympic Games]] is lit by a burning glass, at the site of ancient [[Olympia, Greece|Olympia]] in Greece.<ref>{{cite web |url=http://www.london2012.com/torch-relay/history/ |publisher=London 2012 Olympic Games |title=Olympic Torch Relay history |access-date=27 November 2012 |archive-date=19 July 2012 |archive-url=https://web.archive.org/web/20120719144531/http://www.london2012.com/torch-relay/history/ |url-status=dead }}</ref>

=== Popular culture: verification attempts ===
There have been several real-world tests to evaluate the validity of the legend of Archimedes described above {{crossreference|(see {{slink||War: since the legend of Archimedes}})}} over the centuries, including a test by [[Georges-Louis Leclerc, Comte de Buffon|Comte de Buffon]] (circa 1747), documented in the paper titled "Invention De Miroirs Ardens, Pour Brusler a Une Grande Distance", and an experiment by John Scott, which was documented in an 1867 paper.<ref>{{Cite web |last=Gbur |first=Gregory |author-link=Greg Gbur |date=7 February 2010 |title=Mythbusters were scooped — by 130 years! (Archimedes death ray) |url=https://skullsinthestars.com/2010/02/07/mythbusters-were-scooped-by-130-years-archimedes-death-ray/ |access-date=2022-12-07 |website=Skulls in the Stars |language=en}}</ref>
In 1973, Greek scientist Dr. Ioannis Sakkas, curious about whether Archimedes could really have used a "burning glass" to destroy the Roman fleet in 212 BC, lined up nearly 60 Greek sailors, each holding an oblong mirror tipped to catch the sun's rays and direct them at a wooden ship 160 feet away. The ship caught fire at once. Sakkas said after the experiment there was no doubt in his mind the great inventor could have used bronze mirrors to scuttle the Romans.<ref>{{Cite web |title=Archimedes and his Burning Mirrors, Reality or Fantasy? |url=http://www.mlahanas.de/Greeks/Mirrors.htm |access-date=2022-12-07 |website=www.mlahanas.de}}</ref>

However, accounting for battle conditions makes such a weapon impractical, with modern tests refuting such claims. An experiment was carried out by a group at the [[Massachusetts Institute of Technology]] in 2005. It concluded that although the theory was sound for stationary objects, the mirrors would not likely have been able to concentrate sufficient [[solar energy]] to set a ship on fire under battle conditions.<ref>{{Cite web |title=2.009 Product Engineering Processes: Archimedes<!-- Bot generated title --> |url=http://web.mit.edu/2.009/www//experiments/deathray/10_ArchimedesResult.html |url-status=dead |archive-url=https://web.archive.org/web/20171212185131/http://web.mit.edu/2.009/www/experiments/deathray/10_ArchimedesResult.html |archive-date=2017-12-12 |access-date=2009-12-05}}</ref> Similar experiments were conducted on the popular science-based TV show ''[[MythBusters]]'' in 2004, [[MythBusters (2006 season)#Episode 46 – "Archimedes' Death Ray"|2006]], and [[MythBusters (2010 season)#Episode 157 .E2.80.93 .22President.27s Challenge.22|2010]], arriving at similar results based on the premise of the controversial myth.

However, an episode of ''[[Richard Hammond's Engineering Connections]]'' relating to the [[Keck Observatory]] (whose reflector glass is based on the Archimedes' Mirror) did successfully use a much smaller curved mirror to burn a wooden model, although the scaled-down model was not made of the same quality of materials as in the ''MythBusters'' effort.<ref>{{Citation |title=Richard Hammond Engineering Connections S01E03 – Deep Space Observatory – Keck, Hawaii |url=https://www.youtube.com/watch?v=ix_tsqKzkrQ |language=en |access-date=2022-12-07}}</ref><ref>{{Citation |last=Metcalfe |first=Nick |title=Deep Space Observer |date=23 December 2010 |url=https://www.imdb.com/title/tt1297757/ |series=Engineering Connections |access-date=2022-12-07}}</ref>