Faraday narrowly misses the discovery of the doctrine of
conservation--Carnot's belief that a definite quantity of work can be
transformed into a definite quantity of heat--The work of James Prescott
Joule--Investigations begun by Dr. Mayer--Mayer's paper of 1842--His
statement of the law of the conservation of energy--Mayer and
Helmholtz--Joule's paper of 1843--Joule or Mayer--Lord Kelvin and the
dissipation of energy-The final unification.