During the twenty years following he devoted a large part of his energies to the numerical computation of the lunar inequalities, the redetermination of the elements of motion, and the preparation of new tables for computing the moon's position.
One was a redetermination of the ohm.
Succeeding Maxwell as Cavendish professor of physics at Cambridge in 1880, he soon devoted himself especially to the exact redetermination of the practical electrical units in absolute measure.
Regnault executed a careful redetermination of the specific heats of all the elements obtainable, and of many compounds - solids, liquids and gases.
In particular he carried out a classical redetermination of the velocity of light by A.