A retrospective view of thermodynamics

Based on a critical reading of the original papers that helped found thermodynamics, a retrospective view of thermodynamics is given concerning the often confusing reference to the concept of energy and internal energy, the appropriate combined statements of the first and the second laws of thermodynamics, etc. Also two new statements for the second law, and one new statement for the third law are obtained from the modern understanding of the topics. For example, the third law can also be stated thus: When the temperature approaches the absolute zero, the internal energy U for a thermodynamic system retreats into its energy E.