Bridgman's formulas
The twenty-eight essential results of the Bridgman formula method, according to a 1946 table by American physical chemist Samuel Glasstone. [5]
In thermodynamics, Bridgman formulas or "Bridgman equations" twenty-eight partial derivatives of the ten essential thermodynamic quantities, involving first and second derivatives, expressed in terms of measureable variables. These formulas were systematically derived by American physicist Percy Bridgman in 1914 using what has come to be known as the Bridgman formula method. [1]

Bridgman, in short, presented a clean and organized way of deriving thermodynamic expressions from the partial derivatives of the ten (or ten) main thermodynamic quantities (or variables), P, V, T, E, H, S, A, and F (see: symbols), of which there are 8 x 7 x 6 first (partial) derivatives.

In his 1925 "full version", in contrast to the 1914 "shorter version", of his systematic collection of thermodynamic formulas, he presented the first derivatives of the 10 fundamental quantities, which amounts to 720 equations, organized into 10 groups, based on which variable was held constant during the differentiation. [3]

Bridgman devised a system that allows for the derivation of any of these first partial derivatives in terms of three quantities which are, in general, capable of experimental determination, namely (∂V/∂T)P, (∂V/∂P)T, and (∂H/∂T)P, i.e. CP. The twenty-eight essential formulas derived using this methodology are show adjacent. [1]

1. Bridgman, Percy W. (1914). "A Complete Collection of Thermodynamic Formulas" (abs). Phys. Rev. 3 (4): 273–281.
2. Glasstone, Samuel B. (1946). Thermodynamics for Chemists (Bridgman’s formulas, pg. 212). D. Van Nostrand Co.
3. Percy, Bridgman. (1925). A Condensed Collection of Thermodynamic Formulas. Harvard University Press; in: The Thermodynamics of Electrical Phenomena in Metals. Dover (§Appendix, pgs. 199-242), 1961.

Further reading
● Bridgman, Percy W. (1925). “Condensed Collection of Thermodynamic Formulas”, Phys. Rev.
● Bridgman, Percy W. (1925). A Condensed Collection of Thermodynamic Formulas (34-pages, containing 720 derivatives). Harvard University Press.
● Bridgman, Percy W. (1934). The Thermodynamics of Electrical Phenomena; and a Condensed Collection of Thermodynamics Formulas. Dover, 1961.
● Bridgman, P. W. (1955). “Heat and Thermodynamics” in: Fundamental Formulas of Physics, Volume 1 (ch. 10, pgs. 264-76), by Donald Menzel, Prentice-Hall, 1960.

External links
Bridgman’s thermodynamic equations – Wikipedia.

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