Rules from the book by M. Tribus are explored to deduce specified thermodynamic derivatives of the thermodynamical variables (energy , enthalpy , free energy of Helmholtz , free energy of Gibbs , entropy , temperature , pressure , and volume ) as functions of measurable quantities (temperature , pressure , volume , coefficient of thermal expansion , coefficient of compressibility , heat capacity at constant pressure , and heat capacity at constant volume ). Sometimes the entropy will remain outside the derivatives.