Editing Leonardo da Vinci (section)

== Science and inventions ==
{{Main|Science and inventions of Leonardo da Vinci}}
[[File:De divina proportione - Vigintisex Basium Planum Vacuum.jpg|thumb|upright|[[Rhombicuboctahedron]] as published in [[Luca Pacioli|Pacioli's]] ''[[Divina proportione]]'' (1509)]]

Leonardo's approach to science was observational: he tried to understand a phenomenon by describing and depicting it in utmost detail and did not emphasise experiments or theoretical explanation. Since he lacked formal education in [[Latin language|Latin]] and mathematics, contemporary scholars mostly ignored Leonardo the scientist, although he did teach himself Latin. His keen observations in many areas were noted, such as when he wrote "Il sole non si move" ("The Sun does not move").<ref>{{Cite book |last=Cook |first=Theodore Andrea|author-link=Theodore Andrea Cook |title=The Curves of Life |year=1914 |page=[https://archive.org/details/cu31924028937179/page/n425 390] |url=https://archive.org/details/cu31924028937179 |publisher=Constable and Company Ltd |location=London}}</ref>

In the 1490s he studied mathematics under Luca Pacioli and prepared a series of drawings of regular solids in a skeletal form to be engraved as plates for Pacioli's book ''[[Divina proportione]]'', published in 1509.{{sfn|Arasse|1998}} While living in Milan, he studied light from the summit of [[Monte Rosa]].{{sfn|Wallace|1972|p=145}} Scientific writings in his notebook on fossils have been considered as influential on [[Palaeontology#History|early palaeontology]].<ref>Baucon, A. (2010). "Da Vinci's ''Paleodictyon'': the fractal beauty of traces." In: ''Acta Geologica Polonica,'' p. 60(1). Accessible from the [http://www.tracemaker.com/ author's homepage] {{Webarchive|url=https://web.archive.org/web/20190511153408/http://www.tracemaker.com/ |date=11 May 2019 }}</ref>

The content of his journals suggest that he was planning a series of treatises on a variety of subjects. A coherent treatise on [[anatomy]] is said to have been observed during a visit by Cardinal Louis d'Aragon's secretary in 1517.<ref>{{cite book |last1=O'Malley |last2=Saunders |title=Leonardo on the Human Body |year=1982 |publisher=Dover Publications |location=New York}}</ref> Aspects of his work on the studies of anatomy, light and the landscape were assembled for publication by Melzi and eventually published as ''[[Codex Urbinas|A Treatise on Painting]]'' in France and Italy in 1651 and Germany in 1724,{{sfn|Ottino della Chiesa|1967|p=117}} with engravings based upon drawings by the Classical painter [[Nicolas Poussin]].{{sfn|Heydenreich|2020}} According to Arasse, the treatise, which in France went into 62 editions in fifty years, caused Leonardo to be seen as "the precursor of French academic thought on art."{{sfn|Arasse|1998}}

While Leonardo's experimentation followed scientific methods, a recent and exhaustive analysis of Leonardo as a scientist by Fritjof Capra argues that Leonardo was a fundamentally different kind of scientist from [[Galileo]], [[Isaac Newton|Newton]] and other scientists who followed him in that, as a "[[Polymath|Renaissance Man]]", his theorising and hypothesising integrated the arts and particularly painting.{{sfn|Capra|2007|pp=xvii–xx}}

=== Anatomy and physiology ===
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| caption1 = Anatomical study of the arm ({{circa|1510|lk=no}})
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Leonardo started his study in the [[anatomy]] of the [[human body]] under the apprenticeship of Verrocchio, who demanded that his students develop a deep knowledge of the subject. As an artist, he quickly became master of ''topographic anatomy'', drawing many studies of [[muscle]]s, [[tendon]]s and other visible anatomical features.{{citation needed|date=January 2023}}

As a successful artist, Leonardo was given permission to [[Dissection|dissect]] human corpses at the [[Hospital of Santa Maria Nuova]] in Florence and later at hospitals in Milan and Rome. From 1510 to 1511 he collaborated in his studies with the doctor [[Marcantonio della Torre]], professor of Anatomy at the [[University of Pavia]].<ref>{{cite encyclopedia |url=https://www.britannica.com/biography/Leonardo-da-Vinci/Second-Florentine-period-1500-08 |title=Leonardo da Vinci |encyclopedia=Britannica|access-date=9 August 2022|archive-date=9 August 2022|archive-url=https://web.archive.org/web/20220809222523/https://www.britannica.com/biography/Leonardo-da-Vinci/Second-Florentine-period-1500-08|url-status=live}}</ref> Leonardo made over 240 detailed drawings and wrote about 13,000 words toward a treatise on anatomy.<ref name=Sooke /> Only a small amount of the material on anatomy was published in Leonardo's ''Treatise on Painting''.<ref name=KDK /> During the time that Melzi was ordering the material into chapters for publication, they were examined by anatomists and artists, including [[Giorgio Vasari|Vasari]], [[Benvenuto Cellini|Cellini]] and [[Albrecht Dürer]], who made drawings from them.<ref name=KDK />

Leonardo's anatomical drawings include many studies of the [[human skeleton]] and its parts, and of muscles and sinews. He studied the mechanical functions of the skeleton and the muscular forces that are applied to it in a manner that prefigured the modern science of [[biomechanics]].<ref name=Mason>{{cite book |last=Mason |first=Stephen F. |title=A History of the Sciences |url=https://archive.org/details/historyofscience00maso |url-access=registration |publisher=Collier Books |year=1962 |location=New York |page=[https://archive.org/details/historyofscience00maso/page/550 550]}}</ref> He drew the heart and [[Circulatory system|vascular system]], the [[sex organs]] and other internal organs, making one of the first scientific drawings of a [[fetus]] ''in utero''.<ref name=Popham /> The drawings and notation are far ahead of their time, and if published would undoubtedly have made a major contribution to medical science.<ref name=Sooke>[[Alastair Sooke]],  [https://www.telegraph.co.uk/culture/art/leonardo-da-vinci/10202124/Leonardo-da-Vinci-Anatomy-of-an-artist.html "Leonardo da Vinci: Anatomy of an artist"], ''Daily Telegraph'', 28 July 2013. {{Webarchive|url=https://web.archive.org/web/20191202055415/https://www.telegraph.co.uk/art/artists/leonardo-da-vinci-met-death-dissected-corpses-embryos-hearts/ |date=2 December 2019 }}, accessed 29 July 2013.</ref>

Leonardo also closely observed and recorded the effects of age and of human emotion on the physiology, studying in particular the effects of rage. He drew many figures who had significant facial deformities or signs of illness.{{sfn|Arasse|1998}}<ref name=Popham /> Leonardo also studied and drew the anatomy of many animals, dissecting cows, birds, monkeys, bears, and frogs, and comparing in his drawings their anatomical structure with that of humans. He also made studies of horses.<ref name=Popham />

Leonardo's dissections and documentation of muscles, nerves, and vessels helped to describe the physiology and mechanics of movement. He attempted to identify the source of 'emotions' and their expression. He found it difficult to incorporate the prevailing system and theories of [[humorism|bodily humours]], but eventually he abandoned these physiological explanations of bodily functions. He made the observations that humours were not located in cerebral spaces or [[Ventricular system|ventricles]]. He documented that the humours were not contained in the heart or the liver, and that it was the heart that defined the circulatory system. He was the first to define [[atherosclerosis]] and liver [[cirrhosis]]. He created models of the cerebral ventricles with the use of melted wax and constructed a glass [[aorta]] to observe the circulation of blood through the aortic valve by using water and grass seed to watch flow patterns.<ref name="Jones2012">{{cite journal |last1=Jones |first1=Roger |title=Leonardo da Vinci: anatomist |journal=British Journal of General Practice |volume=62 |issue=599 |year=2012 |page=319 |issn=0960-1643 |doi=10.3399/bjgp12X649241 |pmid=22687222 |pmc=3361109}}</ref>

=== Engineering and inventions ===
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| caption1 = A design for a flying machine ({{circa|1488}}), first presented in the ''[[Codex on the Flight of Birds]]''
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| caption2 = An ''[[Leonardo's aerial screw|aerial screw]]'' ({{circa|1489}}), suggestive of a helicopter, from the ''[[Codex Atlanticus]]''
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During his lifetime, Leonardo was also valued as an engineer. With the same rational and analytical approach that moved him to represent the human body and to investigate anatomy, Leonardo studied and designed many machines and devices. He drew their "anatomy" with unparalleled mastery, producing the first form of the modern technical drawing, including a perfected "exploded view" technique, to represent internal components. Those studies and projects collected in his codices fill more than 5,000 pages.<ref name="guarnieri1">{{Cite journal |last=Guarnieri |first=M. |s2cid=202729396 |year=2019 |title=Reconsidering Leonardo |journal=IEEE Industrial Electronics Magazine |volume=13 |issue=3 |pages=35–38 |doi=10.1109/MIE.2019.2929366 |hdl=11577/3310853 |hdl-access=free}}</ref> In a letter of 1482 to the lord of Milan [[Ludovico il Moro]], he wrote that he could create all sorts of machines both for the protection of a city and for siege. When he fled from Milan to Venice in 1499, he found employment as an engineer and devised a system of moveable barricades to protect the city from attack. In 1502, he created a scheme for diverting the flow of the Arno river, a project on which [[Niccolò Machiavelli]] also worked.<ref>{{cite book |last=Masters |first=Roger |author-link=Roger Masters |title=Machiavelli, Leonardo and the Science of Power |year=1996}}</ref><ref>{{cite book |last=Masters |first=Roger |title=Fortune is a River: Leonardo Da Vinci and Niccolò Machiavelli's Magnificent Dream to Change the Course of Florentine History |publisher=Simon & Schuster |year=1998 |isbn=978-0-452-28090-8}}</ref> He continued to contemplate the canalisation of [[Lombardy#Soils|Lombardy's plains]] while in Louis XII's company{{sfn|Wallace|1972|p=145}} and of the [[Loire]] and its tributaries in the company of Francis I.{{sfn|Wallace|1972|p=164}} Leonardo's journals include a vast number of inventions, both practical and impractical. They include [[Viola organista|musical instruments]], [[Leonardo's robot|a mechanical knight]], hydraulic pumps, reversible crank mechanisms, finned mortar shells, and a [[steam cannon]].{{sfn|Bortolon|1967}}{{sfn|Arasse|1998}}

[[File:Leonardo da Vinci - 1860,0616.99, Studies of military tank-like machines (cropped).jpg|thumb|left|Leonardo's drawings of a scythed chariot and a [[Leonardo's fighting vehicle|fighting vehicle]]]]

Leonardo was fascinated by the phenomenon of [[History of aviation|flight]] for much of his life, producing many studies, including ''[[Codex on the Flight of Birds]]'' ({{circa|1505}}), as well as plans for several flying machines, such as a flapping [[ornithopter]] and a machine with a helical [[Helicopter rotor|rotor]].{{sfn|Arasse|1998}} In a 2003 documentary by British television station [[Channel Four]], titled ''Leonardo's Dream Machines'', various designs by Leonardo, such as a [[Parachute#Early Renaissance|parachute]] and [[Leonardo's crossbow|a giant crossbow]], were interpreted and constructed.<ref>{{cite web |url=https://www.imdb.com/title/tt0365434/ |title=Leonardo's Dream Machines (TV Movie 2003) |website=IMDb|access-date=30 June 2018|archive-date=8 February 2017|archive-url=https://web.archive.org/web/20170208160755/http://www.imdb.com/title/tt0365434/|url-status=live}}</ref><ref>[http://www.bl.uk/onlinegallery/features/leonardo/parachute.html British Library online gallery] {{Webarchive|url=https://web.archive.org/web/20191121011521/http://www.bl.uk/onlinegallery/features/leonardo/parachute.html |date=21 November 2019 }} (retrieved 10 October 2013)</ref> Some of those designs proved successful, whilst others fared less well when tested. Similarly, a team of engineers built ten machines designed by Leonardo in the 2009 American television series ''[[Doing DaVinci]]'', including a [[Leonardo's fighting vehicle|fighting vehicle]] and a [[Leonardo's self-propelled cart|self-propelled cart]].

Research performed by [[Marc van den Broek]] revealed older prototypes for more than 100 inventions that are ascribed to Leonardo. Similarities between Leonardo's illustrations and drawings from the Middle Ages and from Ancient Greece and Rome, the Chinese and Persian Empires, and Egypt suggest that a large portion of Leonardo's inventions had been conceived before his lifetime. Leonardo's innovation was to combine different functions from existing drafts and set them into scenes that illustrated their utility. By reconstituting technical inventions he created something new.<ref>{{citation |mode=cs1 |surname1=[[Marc van den Broek]] |title=Leonardo da Vinci Spirits of Invention. A Search for Traces |publisher=A.TE.M. |location=Hamburg |isbn=978-3-00-063700-1 |date=2019 |language=en}}</ref>

In his notebooks, Leonardo first stated the 'laws' of sliding [[friction]] in 1493.<ref name=Hutchings>{{Cite journal |last=Hutchings |first=Ian M. |date=15 August 2016 |title=Leonardo da Vinci׳s studies of friction |url=http://www.sciencedirect.com/science/article/pii/S0043164816300588 |journal=Wear |language=en |volume=360–361 |pages=51–66 |doi=10.1016/j.wear.2016.04.019 |issn=0043-1648|access-date=22 January 2021|archive-date=12 February 2017|archive-url=https://web.archive.org/web/20170212083723/http://www.sciencedirect.com/science/article/pii/S0043164816300588|url-status=live}}</ref> His inspiration for investigating friction came about in part from his study of [[perpetual motion]], which he correctly concluded was not possible.{{sfn|Isaacson|2017|pp=194–197}} His results were never published and the friction laws were not rediscovered until 1699 by [[Guillaume Amontons]], with whose name they are now usually associated.<ref group="‡" name=":0" /> For this contribution, Leonardo was named as the first of the 23 "Men of Tribology" by [[Duncan Dowson]].<ref>{{Cite journal |last=Dowson |first=Duncan |date=1 October 1977 |title=Men of Tribology: Leonardo da Vinci (1452–1519) |url=https://asmedigitalcollection.asme.org/tribology/article/99/4/382/429918/Men-of-Tribology-Leonardo-da-Vinci-1452-1519 |journal=Journal of Lubrication Technology |language=en |volume=99 |issue=4 |pages=382–386 |doi=10.1115/1.3453230 |issn=0022-2305|doi-access=free|access-date=22 January 2021|archive-date=23 February 2023|archive-url=https://web.archive.org/web/20230223055154/https://asmedigitalcollection.asme.org/tribology/article/99/4/382/429918/Men-of-Tribology-Leonardo-da-Vinci-1452-1519|url-status=live}}</ref>