In chemistry, Geoffroy’s law of affinity is the following statement concerning chemical combinations and reactions concerning the forces of attraction and repulsion between three different chemical entities: [1]
“Whenever two substances are united that have a disposition to combine and a third is added that has a greater affinity with one of them, these two will unite, and drive out the other.”
An alternative fuller translation reads: [2]
“Whenever two substances which have some disposition to unite, the one with the other, are united together and a third which has more affinity for one of the two is added, the third will unite with one of these, separating it from the other.”
Terminologically, this soon came to be known as a "single elective affinity" (single displacement reaction), as contrasted with a "double elective affinity" (double displacement reaction).
History
In 1717-1718, English chemical-physicist Isaac Newton’s famously penned his last and famous Query 31 outlining his final views about chemistry, the forces of chemical action, and chemical reaction.
In 1718, French chemist Etienne Geoffroy, while doing a French-to-English translation of Newton's Opticks, wherein Query 31 is found, conceived of his affinity law, based verbal descriptions of a power series of chemical reactions as described by Newton. [2]
In 1775, Swedish chemist Torbern Bergman, in his A Dissertation on Elective Attractions, add letter symbol notation to Geoffroy's affinity law.
Human chemistry
In 1809, Geoffroy's affinity law, via an 1885 German-translation of Bergman's textbook, was scaled up and applied as the governing universal rule of human-human reactions in German polyintellect Johann Goethe's physical chemistry based novella Elective Affinities. The book has aroused considerable debate ever since, splitting the divide between admirers and enemies.
In 1855, American editor Charles Norton, in semi-ambivalent objection to Goethe’s 1796 human chemical theory, on the premise of his opinion that people are not chemical substances, stated the following: [1]
“The misery of the elective affinities scheme is that men are not chemical substances, and in nine cases out of ten the force of the attraction works more constantly and lastingly upon the woman than the man.”
This point of view, however, conflicts with American physician George Carey's 1919 Chemistry of Human Life, in which he states:
“Man's body is a chemical formula in operation."
This exemplifies a classic dividing line found to be expanding and becoming clarified as led by the HMS pioneers group.
See also
● Geoffroy’s affinity table
References
1. (a) Adler, Jeremy. (1990). "Goethe's use of chemical theory in his Elective Affinities" (ch. 18, pgs. 263-79; Geoffroy’s law of affinity, pg. 265) in Romanticism and the Sciences - edited by Andrew Cunningham and Nicholas Jardine, New York: Cambridge University Press.
(b) Thims, Libb. (2007). Human Chemistry (Volume Two) (pg. 371). Morrisville, NC: LuLu.
2. Geoffroy, Etienne-Francois. (1718). “Concerning the Different Affinities Observed in Chemistry Between Different Substances”, Memoires de l’Academie Royale des Sciences, 202-12; in: A Source Book in Chemistry, 1400-1900 (editors: Henry Leicester, Herbert S. Klickstein). Harvard University Press.
3. Norton, Charles E. (1855). “Memoir of Shelley”, in: The Poetical Works of Percy Bysshe Shelley: in Three Volumes (pg. xxviii). Little, Brown and Co.
