Editing Hermann von Helmholtz (section)

===Mechanics===

His first important scientific achievement, an 1847 treatise on the [[conservation of energy]], was written in the context of his medical studies and philosophical background. His work on energy conservation came about while studying [[muscle]] [[metabolism]]. He tried to demonstrate that no energy is lost in muscle movement, motivated by the implication that there were no ''vital forces'' necessary to move a muscle. This was a rejection of the speculative tradition of ''[[Naturphilosophie]]'' and [[vitalism]] which was at that time a dominant philosophical paradigm in German physiology. He was working against the argument, promoted by some vitalists, that "living force" can power a machine indefinitely.<ref name="Patton">[https://plato.stanford.edu/entries/hermann-helmholtz/?simple=True Patton, Lydia. "Hermann von Helmholtz." (2008), Stanford Encyclopedia of Philosophy.]</ref>

Drawing on the earlier work of [[Nicolas Léonard Sadi Carnot|Sadi Carnot]], [[Benoît Paul Émile Clapeyron]] and [[James Prescott Joule]], he postulated a relationship between [[mechanics]], [[heat]], [[light]], [[electricity]] and [[magnetism]] by treating them all as manifestations of a single ''force'', or [[energy]] in today's terminology. He published his theories in his book ''Über die Erhaltung der Kraft'' (''On the Conservation of Force'', 1847).<ref>English translation published in ''Scientific memoirs, selected from the transactions of foreign academies of science, and from foreign journals: Natural philosophy'' (1853), p. 114; trans. by John Tyndall. [https://books.google.com/books?id=C1i4AAAAIAAJ&pg=PA114 Google Books], [http://hdl.handle.net/2027/uc1.b4252190?urlappend=%3Bseq=124 HathiTrust]</ref>

In the 1850s and 60s, building on the publications of [[William Thomson, 1st Baron Kelvin|William Thomson]], Helmholtz and [[William Rankine]] helped popularize the idea of the [[heat death of the universe]].

In fluid dynamics, Helmholtz made several contributions, including [[Helmholtz's theorems]] for vortex dynamics in inviscid fluids.<gallery>
File:Helmholtz-1.jpg|1889 copy of Helmholtz's "Über die Erhaltung der Kraft", no. 1
File:Helmholtz-2.jpg|Title page of "Über die Erhaltung der Kraft", no. 1
File:Helmholtz-3.jpg|First page of "Über die Erhaltung der Kraft", no. 1
</gallery>