Editing Jean-Paul Marat (section)

==Scientific writing==
Marat set up a laboratory in the [[L'Aubespine|Marquise de l'Aubespine]]'s house with funds obtained by serving as court doctor among the aristocracy. His method was to describe in detail the meticulous series of experiments he had undertaken on a problem, seeking to explore and then exclude all possible conclusions but the one he reached.

He published works on fire and heat, [[electricity]], and light. He published a summary of his scientific views and discoveries in ''Découvertes de M. Marat sur le feu, l'électricité et la lumière'' (English: ''Mr Marat's Discoveries on Fire, Electricity and Light'') in 1779.  He published three more detailed and extensive works that expanded on each of his areas of research.

=== ''Recherches Physiques sur le Feu'' ===
The first of Marat's large-scale publications detailing his experiments and drawing conclusions from them was ''Recherches Physiques sur le Feu'' (English: ''Research into the Physics of Fire''), which was published in 1780 with the approval of the official censors.<ref>[[#Conner1999|Conner (1999)]], p. 71</ref>

This publication describes 166 experiments conducted to demonstrate that fire was not, as was widely held, a material element but an "[[Igneous rock|igneous]] fluid." He asked the [[French Academy of Sciences|Academy of Sciences]] to appraise his work, and it appointed a commission to do so, which reported in April 1779. The report avoided endorsing Marat's conclusions but praised his "new, precise and well-executed experiments, appropriately and ingeniously designed". Marat then published his work, with the claim that the Academy approved of its contents.  Since the Academy had endorsed his methods but said nothing about his conclusions, this claim drew the ire of [[Antoine Lavoisier]], who demanded that the Academy repudiate it.  When the Academy did so, this marked the beginning of worsening relations between Marat and many of its leading members. A number of them, including Lavoisier himself, as well as [[Marquis de Condorcet|Condorcet]] and [[Pierre-Simon Laplace|Laplace]], took a strong dislike to Marat.  However, [[Jean-Baptiste Lamarck|Lamarck]] and [[Bernard Germain de Lacépède|Lacépède]] wrote positively about Marat's experiments and conclusions.<ref>[[#Conner1999|Conner (1999)]], pp. 77–79</ref>

=== ''Découvertes sur la Lumière'' ===
In Marat's time, [[Isaac Newton|Newton]]'s views on light and colour were regarded almost universally as definitive, yet Marat's explicit purpose in his second major work ''Découvertes sur la Lumière'' (''Discoveries on Light'') was to demonstrate that in certain key areas, Newton was wrong.<ref name="E&D">{{cite journal |last1=Baillon |first1=Jean-François |year=2009 |title=Two Eighteenth-Century Translators of Newton's Opticks: Pierre Coste and Jean-Paul Marat |url=http://www.qmulreligionandliterature.co.uk/wp-content/uploads/2015/12/2520092.pdf |journal=Enlightenment and Dissent |volume=25 |pages=1–28 |access-date=6 November 2018 |archive-date=7 November 2018 |archive-url=https://web.archive.org/web/20181107010312/http://www.qmulreligionandliterature.co.uk/wp-content/uploads/2015/12/2520092.pdf |url-status=dead }}</ref>

The focus of Marat's work was the study of how light bends around objects, and his main argument was that while Newton held that white light was broken down into colours by [[refraction]], the colours were actually caused by [[diffraction]].  When a beam of sunlight shone through an aperture, passed through a prism and projected colour onto a wall, the splitting of the light into colours took place not in the prism, as Newton maintained, but at the edges of the aperture itself.<ref>[[#Conner1999|Conner (1999)]], pp. 89–95</ref> Marat sought to demonstrate that there are only three [[Primary color|primary colours]], rather than seven as Newton had argued.<ref>[[#Conner1999|Conner (1999)]], pp. 105–106</ref>

Once again, Marat requested the Academy of Sciences review his work, and it set up a commission to do so. Over a period of seven months, from June 1779 to January 1780, Marat performed his experiments in the presence of the commissioners so that they could appraise his methods and conclusions. The drafting of their final report was assigned to [[Jean-Baptiste Le Roy]]. The report was finally produced after many delays in May 1780, and consisted of just three short paragraphs. Significantly, the report concluded that ''"these experiments are so very numerous...[but]...they do not appear to us to prove what the author believes they establish".''<ref name="E&D"/> The Academy declined to endorse Marat's work.<ref>[[#Conner1999|Conner (1999)]], pp. 94–95</ref> When it was published, ''Découvertes sur la lumière'' did not carry the royal approbation. According to the title page, it was printed in London, so that either, Marat could not get the official censor to approve it, or, he did not want to spend the time and effort to do so.

=== ''Recherches Physiques sur L'Électricité'' ===
Marat's third major work, ''Recherches Physiques sur l'Électricité'' (English: ''Research on the Physics of Electricity''), outlined 214 experiments. One of his major areas of interest was in [[Magnetism|electrical attraction and repulsion]].  Repulsion, he held, was not a basic force of nature. He addressed a number of other areas of enquiry in his work, concluding with a section on [[lightning rods]] which argued that those with pointed ends were more effective than those with blunt ends, and denouncing the idea of "[[earthquake rods]]" advocated by [[Pierre Bertholon de Saint-Lazare]]. This book was published with the censor's stamp of approval, but Marat did not seek the endorsement of the Academy of Sciences.<ref>[[#Conner1999|Conner (1999)]], p. 132</ref>

In April 1783,<ref name="Conner 1999, p. 35"/> he resigned his court appointment and devoted his energies full-time to scientific research. Apart from his major works, during this period Marat published shorter essays on the medical use of electricity (''Mémoire sur l'électricité médicale'' (1783)) and on optics (''Notions élémentaires d'optique'' (1784)). He published a well-received translation of Newton's ''[[Opticks]]'' (1787), which was still in print until recently,{{When|date=July 2022}} and later a collection of essays on his experimental findings, including a study on the effect of light on soap bubbles in his ''Mémoires académiques, ou nouvelles découvertes sur la lumière'' (''Academic memoirs, or new discoveries on light'', 1788). [[Benjamin Franklin]] visited him on several occasions and [[Johann Wolfgang von Goethe|Goethe]] described his rejection by the Academy as a glaring example of scientific despotism.