The sum of actual and potential energies in the universe is unchangeable.
—William John Macquorn Rankine1
1. Nineteenth-century Scottish engineer and scientist who made fundamental contributions to the development of thermodynamics; inventor of the Rankine cycle for conversion of heat into mechanical energy/work. The Rankine temperature scale is named after him. Quotation source: Rankine, W. J. M., “On the general law of the transformation of energy,” Philosophical Magazine, Vol. 5, No. 30, 1853, pp. 106–117.
This quote by William Rankine is simply an alternative statement of the principle of the conservation of energy or the first law of thermodynamics—that energy can be neither created nor destroyed. This ...