In a temperature-volume diagram ($$T$$-$$V$$ graph), an adiabatic curve $$\sim V^{1-\gamma}$$ was plotted. The product $$T_1 \, {V_1}^{\gamma-1}$$ BEFORE the adiabatic process is equal to the product $$T_2 \, {V_2}^{\gamma-1}$$ AFTER the process.