In thermodynamics, history of human thermodynamics traces the timeline of ideas and people involved in the development and inception of the modern theory of human thermodynamics. In a sense, the history of human thermodynamics traces the use and application of the laws of thermodynamics in the understanding of the process of human life, both internally (with in the body) and externally (between bodies).

Overview
In 1824, French physicist Sadi Carnot, the founder of thermodynamics, published his turning-point paper “Reflections on the Motive Power of Fire”, which outlined the basics of the laws of generalized heat engines, i.e. any generalized body whatsoever that performs work due to the action of heat. In the decades to follow, scientists, researchers, and philosophers have been forever since striving to understand how the process of human life operates through the lens of thermodynamics.

In 1852, William Thomson published his "On a Universal Tendency in Nature to the Dissipation of Mechanical Energy" in which he set forth the generalized over-simplified view, for many readers, that all natural systems tend to down grade in energy over time.

In 1856, Danish civil engineer and physicist Ludwig Colding published a paper titled "Scientific reflections on the relationship between intellectual life’s activity and the general forces of nature" in relation to his work in the calculation of the mechanical equivalent of heat.

In 1856,
French physicist Gustave Hirn was conducting experiments in the determination of the mechanical equivalent of heat of a human being in working action. In particular, Hirn calculated a value for the mechanical equivalent of heat for a man doing work, i.e. running on a paddle-wheel like stair-climber treadmill, in a sealed chamber. To achieve this end, a man was placed in a hermetically closed chamber, and made to turn a wheel which could, at choice, revolve with or without doing work. The heat given out in the chamber was then ascertained by the ordinary calorimetric process. From these experiments, Hirn deduced a valuation of the mechanical equivalent of heat for animated motors; but the number which he obtained differed considerably from the standard obtained by Joule via physico-mechanical methods. [5]

In 1869, Irish author Joseph Murphy applied the then-developing principles of thermo-dynamics, which he define as the theory that proved that “heat consists in molecular motions, and that the laws of heat are only a particular case of the laws of force”, to develop a loose outline of the “dynamics of life”. [4] In doing so, he compared the animal organism to the steam engine, and reasoned that a “vital energy”, a variable quantity of static actual energy, which is capable of being transformed when needed either into heat or into muscular motor power. He regarded vital energy as “a distinct form of actual energy, just like heat, electricity, magnetism, or the energy of motion.

In 1873, French scientist Etienne-Jules Marey, in his La Machine Animale or Animal Mechanism: A Treatise on Terrestrial and Aërial Locomotion (1874 English translation), devoted a small section to what he called "thermo-dynamics applied to living beings". In it he stated, in reference to a theory of animal thermo-dynamics, wherein energies (or forces) involved in digestion, respiration, and excretion, etc., would need to be accounted for, that: “this complication in the measure of force among organized beings shows what difficulties await those who are endeavoring to verify the principles of thermo-dynamics in animals; yet, nevertheless, he continues, “it would be illogical to admit without proof that, in living beings, the physical forces do not obey natural laws”. [5] He continues, “several savants, firmly convinced of the generality of the laws of thermo-dynamics, have attempted to demonstrate them upon animal organism.” He cites Hirn, among others.

In 1893, English engineer Bryan Donkin, in his "The Scientific Work of Gustav Adolph Hirn", was using the term "human thermo-dynamics", in reference to the work of Hirn.

In 1895 to 1910, American historian and lawyer Brooks Adams and his brother Henry Adams published a number of works of history and society based on thermodynamics.

In 1952, C.G. Darwin, in his The Next Million Years, explicitly defined human thermodynamics as the study of systems of human molecules.

In 1956, Mehdi Bazargan published Thermodynamics of Humans, the first book titled "human thermodynamics".

In 2007, Libb Thims, in his Human Chemistry, published a chapter on "human thermodynamics", in which systems of humans constitute chemical systems of substrate attached human molecules. [2]

References
1. (a) Darwin, Charles G. (1952). The Next Million Years (pg. 26). London: Rupert Hart-Davis.
(b) Thims, Libb. (2007). Human Chemistry (Volume One), (preview). (pgs. 25-35) Morrisville, NC: LuLu.
2. Thims, Libb. (2007). Human Chemistry (Volume One), (preview), (Ch. 16: "Human Thermodynamics", pgs. 653-702). Morrisville, NC: LuLu.
4. Murphy, Joseph J. (1869). Habit and Intelligence in Their Connexion with the Laws of Matter and Force (ch. 8: “The Chemistry of Life”, pgs. 84-89; ch. 9: “The Dynamics of Life”, pgs. 90-109). Macmillan and Co.
5. Marey, Étienne-Jules. (1973). La Machine Animale (Animal Mechanism: A Treatise on Terrestrial and Aërial Locomotion), (pg. 13-18). D. Appleton and Co.
6. M.A.E. (1893). Transactions of the Manchester Association of Engineers, (ch. 5: "Human Thermodynamics", pgs. 176-183). Manchester: Herald & Walker, Printers.

External links
Human Thermodynamics: History - Institute of Human Thermodynamics

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