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European Journal of Applied Sciences – Vol. 12, No. 1
Publication Date: February 25, 2024
DOI:10.14738/aivp.121.16448
Mitrovic, J. (2024). The Roots of the Thermodynamic Laws. European Journal of Applied Sciences, Vol - 12(1). 442-448.
Services for Science and Education – United Kingdom
The Roots of the Thermodynamic Laws
Jovan Mitrovic
Stuttgart, Germany
ABSTRACT
Historians of thermodynamics usually consider the Sadi Carnot’s memoir, appeared
in 1824, as the origin of modern thermodynamics. A closer inspection of published
works tells us another story. More than five decades prior to Carnot’s publication
the Scottish instrument’s maker, whose name was James Watt, issued his ideas on
thermodynamics. Today Watt is well known as originator of various ideas,
particularly for his perfection of the steam engine. However, he is almost unknown
as a scientist of thermodynamics. The present paper illustrates some of Watt’s
original thermodynamic ideas which he obtained from the hidden principles of the
steam engine. In around 1769 he recognized and formulated the foundations of
modern thermodynamics. He illustrated the working principle of the steam engine
by using the 1st and the 2nd law of thermodynamics which were absolutely unknown
at that time. Despite these facts, the name of James Watt is banished from the history
of thermodynamics. The Watt’s understanding and presentation of these laws are
the pivotal subject of the present work.
Keywords: James Watt, irreversible thermodynamics, Sadi Carnot, energy conservation
energy conversion; first law and second law of thermodynamics.
INTRODUCTION
In 1824 Sadi Carnot [1] published the memoir Reflections on the Motive Power of Fire aiming at
formulation of a general theory of heat engines. The work contains his thermodynamics and
links numerous novel ideas into a coherent whole, which has led some authors to consider the
publication year of the Reflections as the birth of modern thermodynamics. However, Carnot
did not provide any State of the Art and the reader is required to consider him as the true
creator of these ideas. 1 In the Reflections Carnot mentions several scientists who have
contributed to the development of steam engine but emphasized only one as famous, namely,
James Watt (p. 42 in [1]). In the Appendix B (Carnot’s Foot-Notes, p. 253), he makes additional
references to Watt’s work:
Watt, to whom we owe almost all the great improvements in steam-engines and
who brought these engines to a state of perfection difficult even now to surpass, was
also the first who employed steam under progressively decreasing pressures. ...
1 The importance of the State-of-the-Art has been stressed already in 1810 by the German philosopher and poet Johann
Wolfgang von Goethe (Theory of Colors, English translation Charles Lock Eastlake, JOHN MURRAY, 1840, Preface to the
First Edition1810, pp. XXIV/XXV): As we before expressed the opinion that the history of an individual displays his
character, so it may here be well affirmed that the history of science is science itself. We cannot clearly be aware of what
we possess till we have the means of knowing what others possessed before us. We cannot really and honestly rejoice
in the advantages of our own time if we know not how to appreciate the advantages of former periods
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Mitrovic, J. (2024). The Roots of the Thermodynamic Laws. European Journal of Applied Sciences, Vol - 12(1). 442-448.
URL: http://dx.doi.org/10.14738/aivp.121.16448
From this citation we may conclude that Carnot was very familiar with the Watt’s
thermodynamic works (Mitrovic, 2022a [2]). In addition, Carnot was aware of the contributions
made by English engineers. Actually, he is credited with numerous ideas in thermodynamics,
including the traces of the second law. Several historians of thermodynamics consider Sadi
Carnot to be the father of modern thermodynamics, see for instance Mitrovic [3].
In publications we often find the statement: Carnot formulated the second law although the
first law was unknown. This statement is double incorrect: Carnot did not formulate the second
law, nor was the first law unknown in Carnot’s time. However, the assessment of Carnot’s
Reflections by the mathematician Clifford Truesdell [4] deserves particular attention (p. 79,
Carnot, 5. Act II, Dissipationless Work):
... Little of any consequence regarding this subject was then known. Anyone
sceptical here need not resort to the writings of engineers, inventors, and
constructors. Just eight years before Carnot’s work was published, a leading
physicist of the day (J. B. Biot) could give his readers in a whole chapter on steam
engine no more than an illustrated description of the machines, embellished by a
few scientific terms and some numerical data regarding them, followed by a sketch
of their evolutions during the preceding 111 years, and finish with the discussion of
how much work a horse of mean strength can do in a day. (Emphasis added).
Apparently, Truesdell did not know that Sadi Carnot was educated military engineer. In
addition, Truesdell’s book allows the conclusion that thermodynamics did not exist before
Carnot’s Reflections and that Carnot would formulate this noble discipline as a science from
nothing.
Figure 1: James Watt, 1736-1819.
The Scottish Engineering Hall of Fame, James Watt (https://engineeringhalloffame.org/profile/james-watt.);
Genius whose thermodynamics was ignored or not understood for 250 years.
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The aim of the present work is not the thermodynamics of Sadi Carnot himself. His
thermodynamics is well-known from the original publication and from numerous secondary
sources, for example [5] Barnett, 1958; [6] Dias et al., 1995. The rest of the present work is an
excerpt from the thermodynamics of James Watt (Figure 1). Its aim is to focus the reader’s
attention on the thermodynamic laws as they were recognised, developed and applied in the
practice for the first time by James Watt in 1769, more than 250 fifty years ago.
The Watt’s 1st law follows immediately from his drawings of the steam engines. It is associated
with the splitting of energy (heat) the working substance receives in the boiler. The 2nd law is
associated with the low temperature steam that is liquified in the separate condenser of the
steam engine. This law follows almost directly from the Watt’s expression stating the 1st law.
These two laws represent a coherent unit.
THE JAMES WATT LAWS OF THERMODYNAMICS
Watt visualised these laws by drawings of the steam engines. In the drawings, he indicated the
flows of matter and energy and gives the reader the opportunity to overlook the entire idea at
a glance. Here we sketch the Watt’s way of presentation.
The First Law
Figure 2 left shows the Watt’s original drawing of a steam engine facility built and used as a
part of his patent in 1769, taken from Kelly [7]. It illustrates the Watt’s idea on the transport of
heat and work in the installation. In shorth: The heat taken with steam from the boiler is split
in the steam cylinder in a low temperature heat (steam) and work. The low temperature steam
is liquified in the separate condenser and the condensate is transported by a pump in the boiler.
By means of a beam the work is used to operate the condensate pump and an additional pump,
that transports the drain water, collected in the bottom of the mine, outside of the steam engine
installation.
Figure 2 right shows some details of energy (heat) splitting in the steam cylinder. So far as I
understand, by splitting the heat in the steam cylinder James Watt recognised and applied for
the first time (1769) in the history of thermodynamics two important properties of energy,
namely, its convertibility and conservativity; the latter we call the 1st Law of thermodynamics.
This Law can be casted into a simple equation, that immediately follows from the Watt’s
drawing in Figure 2 right [2, 8, 9]:
QB = W + QC . (Watt’s 1st Law) (1)
Here QB denotes the high temperature heat that the working substance absorbs in the boiler,
W is the work performed by the steam, and QC is the heat of the low temperature steam
liquefied in the engine’s condenser. We may call Eq. (1) the James-Watt Energy Equation.
Usually, the low temperature heat is considered as energy loss of the process in question,
although the energy (heat) of the steam liquified in the condenser could be used in an
associated process. Clausius provides on pp. 1-2 in [10] a discussion of the issue.
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Mitrovic, J. (2024). The Roots of the Thermodynamic Laws. European Journal of Applied Sciences, Vol - 12(1). 442-448.
URL: http://dx.doi.org/10.14738/aivp.121.16448
Figure 2 left: James Watt’s installation of single acting steam engine 1769 [7]. Figure 2 right:
The Watt’s idea of heat splitting in the steam cylinder, [2, 8, 9].
Energy Transport and Irreversibility
In order to reduce the heat losses, Watt insulated the components of the steam engine
installation against the ambient by different low conductivity materials (Figure 2). The steam
cylinder was of particular importance, because of steam saturation any heat loss caused steam
condensation in the cylinder which Watt tried to prevent. To arrive at a satisfying solution, he
devised a novel, ingenious design of the steam cylinder, Figure 3. He jacketed the steam cylinder
by a layer of saturated steam (taken from the boiler) and suppressed almost completely the
heat losses from the steam inside the main cylinder to the ambient. In modern terminology,
Watt reduced the irreversibility of his steam engine installation associated with heat losses. His
idea on heat losses and the irreversibility published in 1769 was the first of this kind in thermal
science and most likely has been forgotten over time. For, about 170 years later, in 1938, Fran
Bosnjakovic, without mentioning James Watt, took up the fight against irreversibility and called
on the researches to support his program. (Bošnjaković, F., 1938, Kampf den
Nichtumkehrbarkeiten (Fight against irreversibility), publ. in Arch. für Wärmewirtschaft und
Dampfkesselwesen, 1938, 19, 1-2, in German).
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In this context we should mention that Sadi Carnot’s cycle of 1824 contains some heat transfer
processes under the assumption of (nearly) zero temperature difference. This assumption
reduces the irreversibility and simultaneously the kinetic of the heat transfer process almost to
zero; in other words, it renders the process not realizable and the cycle not feasible. Carnot did
not mention any Watt’s work in this context. The reader is left alone with the question: What
did Carnot take from James Watt and which were his own ideas? Note that Watt was the first
scientist to accomplish the closed cyclic flow of working substance in the steam engine.
Figure 3: James Watt’s type of steam cylinder, jacketed by a layer of saturated steam, 1769. Due
to the equal steam temperatures inside the cylinder and in the jacket, Watt ideally suppressed
heat losses from the steam in the main cylinder to the surroundings. The rapidity of the
processes taking place inside the cylinder was not diminished [3, 11].
For details of James Watt’s thermodynamics, the reader is referred to the papers by J. Mitrovic,
some of which are mentioned in the present work. Of innumerable publications on
thermodynamics there are several excellent books and review papers. The paper by T.S. Kuhn
[12] is recommended as a masterwork. However, Kuhn apparently did not recognise the true
scientific worth of Watt’s thermodynamics.
Watt’s View of the Second Law
The parts of this paragraph are taken from the author’s paper Irreversible thermodynamics of
James Watt [8]. An analysis of the Watt’s energy equation, Eq. (1), provides further insights into
his thermodynamics. We note first that the quantities W and QC in this equation are positive
quantities,
W > 0 , QC > 0 . (2)
Considering the expression (2), the first law, Eq. (1), delivers:
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Mitrovic, J. (2024). The Roots of the Thermodynamic Laws. European Journal of Applied Sciences, Vol - 12(1). 442-448.
URL: http://dx.doi.org/10.14738/aivp.121.16448
QB > W and QB > QC . (3)
Like Eq. (1), the expression (3) states:
The energy (heat) QB the working substance absorbs in the boiler cannot be completely
converted into the work W, a part of it, QC, must be wasted in the separate condenser.
While work can be fully converted into heat, the wasted heat QC limits the conversion of the
heat QB into the work W and makes the conversion processes W→ Q and Q→ W asymmetrical
and irreversible. This is an addition to the Watt’s first law that can be viewed as another, distinct
law of thermodynamics. Being deduced solely from the Watt’s works it seems reasonable to call
it the Watt’s formulation of the second law of thermodynamics. The formulation of the second
law uses physical quantities to express the boundary of a possible, real process. As long as the
heat QB in Eq. (1) satisfies the first law, this heat can be converted into the work W, not
completely, but only partially. This explanation of Watt’s results is reasonable because the
second law requires the knowledge about the energy convertibility according to the first law. It
connects the first and the second law in a logical sequence. Based on the first principle, the
second law is formulated on the basis of simple algebra, without any imaginary or impossible
processes. The second law according to James Watt represents the origin of several
synonymous wordings. As example I mention only the formulation by Max Planck [13]. In §108,
Planck states that not every change which is consistent with the principle of the conservation
of energy satisfies also the additional conditions which the second law imposes upon the
processes, which actually take place in nature. ... Planck continues, we often find the second law
stated as follows:
The change of mechanical work into heat may be complete, but, on the contrary,
that of heat into work must needs be incomplete, since, whenever a certain quantity
of heat is transformed into work, another quantity of heat must undergo a
corresponding and compensating change; e.g., transference from higher to lower
temperature.
... And in §116: The second fundamental principle of thermodynamics being, like the first, an
empirical law, we can speak of its proof only in so far as its total purport may be deduced from
a single self-evident proposition. We, therefore, put forward the following proposition as being
given directly by experience:
It is impossible to construct an engine which will work in a complete cycle, and
produce no effect except the raising of a weight and the cooling of a heat-reservoir.
A more precise wording of the Watt’s expressions (3) stating the second law seems scarcely
possible. This wording poses the question: Did Max Planck study and analyse the James Watt’s
thermodynamic ideas?
CONCLUSION
James Watt is well-known as a mechanical engineer for his construction, particularly, of steam
engines. In the present paper I have discussed some Watt’s ideas which make the scientific
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origin of modern thermodynamics. Watt was the first to analyse heat losses and irreversibility
of the steam engine. But he was also the first to establish the conditions for a possible reversible
heat transfer. However, of pivotal importance for the history of thermodynamics is his
understanding, formulation and application of important relationships which are today called
the 1st and the 2nd law of thermodynamics. Despite these facts the name Jams Watt is banished
from the history of thermodynamics.
References
[1] Carnot, S. (1897). Reflections on the Motive Power of Fire, and on Machines Fitted to Develop That Power
(Translated and Edited by R.H. Thurston, 1897). John Wiley.
[2] Mitrovic, J. (2022a). Some Ideas of James Watt in Contemporary Energy Conversion Thermodynamics.
Journal of Modern Physics, 13, 385-409. https://doi.org/10.4236/jmp.2022.134027.
[3] Mitrovic, J. (2023). Sadi Carnot and the Thermodynamics of James Watt. Advances in Historical Studies,
12, 47-62; https://doi.org/10.4236/ahs.2023.122004.
[4] Truesdell, C. A. (1980). The Tragicomical History of Thermodynamics 1822-1854. Springer;
https://doi.org/10.1007/978-1-4613-9444-0.
[5] Barnett, M. K. (1958). Sadi Carnot and the Second Law of Thermodynamics. Osiris, 13, 327-357;
https://www.jstor.org/stable/301653; https://doi.org/10.1086/368620.
[6] Dias, P. M. C., Pinto, S. P., & Cassiano, D. H. (1995). The Conceptual Import of Carnot’s Theorem to the
Discovery of the Entropy. Archive for History of Exact Sciences, 49, 135-161;
https://www.jstor.org/stable/41134002; https://doi.org/10.1007/BF00376545.
[7] Kelly, M. (2002). The Boulton & Watt Engine, The Non Rotative Beam Engine, Chapter 3, Somerset Great
Britain;
https://www.thehopkinthomasproject.com/TheHopkinThomasProject/TimeLine/Wales/Steam/James
Watt/Kelly/Watt.htm.
[8] Mitrovic, J. (2022b). Irreversible Thermodynamics of James Watt. Advances in Historical Studies, 11, 119-
128; https://doi.org/10.4236/ahs.2022.113011.
[9] Mitrovic, J. (2022c). Who Established the First Law of Thermodynamics? Chemie Ingenieur Technik,
Volume 94, Issue 6, pp. 823-826; https://doi.org/10.1002/cite.
[10] Clausius, R. Über die bewegende Kraft der Wärme, und die Gesetze, welche sich daraus für die
Wärmelehre selbst ableiten lassen, Poggendorff's Annalen der Physik, 79, pp. 368–397, 500–524, 1850;
Philosophical Magazine, Series 4, Vol. 2, No. 8, pp. 1–21, 102–119, July 1851.
[11] Farey, J. A Treatise on the Steam Engine: Historical, Practical, and Descriptive (London: Longman, Rees,
Orme, Brown, and Green, 1827), p. 333; also [3].
[12] Kuhn, T. S., Energy Conservation as an Example of Simultaneous Discovery, in: M. Clagett ed., Critical
Problems in the History of Science: proceedings of the Institute for the History of Science at the
University of Wisconsin, September 1-11, 1957 (Wisconsin 1959) 321-356.
[13] Planck, M. Treatise on Thermodynamics, English by A. Ogg, Dover Publications Inc., 1910.