Title page to a 1960 English translation of French physicist Emile Clapeyron's 1834 "Memoir on the Motive Power of Heat" by Eric Mendoza. [2] |

**Memoir on the Motive Power of Fire**” is an 1834 article written by French physicist Emile Clapeyron that expanded on the earlier 1824 booklet

*Reflections on the Motive Power of Fire*, by French physicist Sadi Carnot, via the use of a more rigorous mathematical formulation and the use of the pressure-volume indicator diagram technique, developed in 1796 by James Watt and John Southern, to facilitate a graphical calculation of pressure-volume work. [1] The central function of Clapeyron's

*Memoir*was to introduce other physicists, particularly Thomson and Clausius, to Carnot's

*Reflections.*

Notes

Clapeyron is said to have begun work on his

*Memoir*after returning from Russian in 1830. Clapeyron's

*Memoir*was more widely circulated than was Carnot's book and was translated into English and German. [3]

Indicator diagrams

In 1796, Scottish instrument maker James Watt and his employee John Southern developed a work measurement tool called an "indicator diagram", used to exactly quantify the work produced by a steam engine, which made a chart of the pressure of the steam in a cylinder plotted out against the steam's volume:

Pressure volume work

Using data from the indicator diagram, in 1834, Clapeyron the first to employ a graphical analysis of the measure of the work done by the expansion or contraction of the steam, the work of the steam can be determined using calculus:See main: Pressure volume work

where

*W*is the work done by the body of steam,

*Vi*is the initial volume,

*Vf*is the final volume, and

*P*is the pressure of the steam. Clapeyron used the phrase "mechanical action" as the measure of this integral.

References

1. (a) Clapeyron, Emile. (1834). “Memoir on the Motive Power of Heat.”

*Journal de l’Ecole Polytechnique*, XIV, 153.

(b) Clapeyron, Emile. (1843). “Memoir on the Motive Power of Heat.”

*Annalen der Physik,*LIX, 446, 566.

2. Carnot, Sadi, Clapeyron, Emile, Clausius, Rudolf, Mendoza, Eric. (1960).

*Reflections on the Motive Power of Fire and Other Papers on the Second Law of Thermodynamics by E. Clapeyron and R. Clausius, edited with an Introduction by E. Mendoza.*Dover.

3. Shachtman, Tom. (1999).

*Absolute Zero and the Quest for Absolute Cold*(pgs. 85-86). Mariner Books.

Further reading

● Edmunds, C.K. (1902). “The Motive Power of Heat”,

*Harper’s Magazine*, Dec. pgs. 117-.