This principle is applicable not only to heat, the most general and most widelydiffused form of motion, but to other forms as well. in every case, it is always justthe one term in the chain of the three interchangeable motions, the character of themolecular work, that is changed. Work of disgregation and mechanical work can bedone, e.g., by electricity as well as by heat. There are, therefore, various kinds ofmolecular work; but there is in the last resort only one work of disgregation, asthere is only one form of mechanical work. Disgregation is the name given, inevery instance, to a permanent change of the distances separating the molecules, nomatter what cause has produced it.