The law may apparently be " a general rule " or " a tendency " which is liable to be " checked," or a particular case of the law of the conservation of energy.
Thomson (Lord Kelvin), he may be regarded as one of the founders of the now universally received law of the conservation of energy.
The principle which he adopted is that of virtual velocities, a principle which under his hands was gradually transforming itself into what is now known as the principle of the conservation of energy.
On the other hand it is asserted that quite apart from any particular view as to the relation between mind and body the existence of the freedom of the will is necessarily incompatible with the principle of the conservation of energy and is therefore in direct contradiction to many if not most of the assured conclusions of the physical sciences.
Colding, who in 1843 presented to the Royal Society of Copenhagen a paper entitled "Theses concerning Force," which clearly stated the "principle of the perpetuity of energy," and who also performed a series of experiments for the purpose of determining the heat developed by the compression of various bodies, which entitle him to be mentioned among the founders of the modern theory of energy, we come to Dr James Prescott Joule of Manchester, to whom we are indebted more than to any other for the establishment of the principle of the conservation of energy on the broad basis on which it has since stood.
