<P> Both Joule's and Mayer's work suffered from resistance and neglect but it was Joule's that eventually drew the wider recognition . </P> <P> In 1844, William Robert Grove postulated a relationship between mechanics, heat, light, electricity and magnetism by treating them all as manifestations of a single "force" (energy in modern terms). In 1846, Grove published his theories in his book The Correlation of Physical Forces . In 1847, drawing on the earlier work of Joule, Sadi Carnot and Émile Clapeyron, Hermann von Helmholtz arrived at conclusions similar to Grove's and published his theories in his book Über die Erhaltung der Kraft (On the Conservation of Force, 1847). The general modern acceptance of the principle stems from this publication . </P> <P> In 1850, William Rankine first used the phrase the law of the conservation of energy for the principle . </P> <P> In 1877, Peter Guthrie Tait claimed that the principle originated with Sir Isaac Newton, based on a creative reading of propositions 40 and 41 of the Philosophiae Naturalis Principia Mathematica . This is now regarded as an example of Whig history . </P>

Who invented the law of conservation of energy