In 1901 the Copley medal of the Royal Society of London was awarded him as being "the first to apply the second law of thermodynamics to the exhaustive discussion of the relation between chemical, electrical and thermal energy and capacity for external work."
A dissolved in B and B dissolved in A, since both of these solutions emit vapours of the same composition (this follows since the same vapour must be in equilibrium with both solutions, for if it were not so a cyclic system contradicting the second law of thermodynamics would be realizable).
This not only verifies that the second law of thermodynamics is obeyed, but enables us to identify T with the absolute thermodynamical temperature.
Such a result must be regarded as impossible of attainment, as it would imply the possibility of heat passing from one body to another at a higher temperature, contrary to the second law of thermodynamics.
Consider an elementary couple of two metals A and B for which s has the values s and s" respectively, with junctions at the temperature T and T+dT (absolute), at which the coefficients of the Peltier effect are P and P+dP. Equating the quantity of heat absorbed to the quantity of electrical energy generated, we have by the first law of thermodynamics the relation dE/dT =dP/dT+(s' - s").
