Abstract: A treatment for reversible and irreversible processes or cycles by the Clausius＇ method is introduced and some aspects related to the method are debated. Another method of entropy deduction is mentioned, treatments of adiabatic processes with different methods are compared, and then an indispensable assumption of Clausius＇ method is clarified.

Key words: Clausius method, Carnot cycle, static assumptions, thermodynamic potential energies, net heat, Fermi＇ s method