Heat can never pass from a colder to a warmer body without some other change, connected therewith, occurring at the same time.

- Rudolf Clausius

The energy of the universe is constant.

- Rudolf Clausius

The total energy of the universe is constant; the total entropy is continually increasing.

- Rudolf Clausius

In all cases where work is produced by heat, a quantity of heat proportional to the work done is expended; and inversely, by the expenditure of a lik…

- Rudolf Clausius

The algebraic sum of all the transformations occurring in a cyclical process can only be positive, or, as an extreme case, equal to nothing. Statemen…

- Rudolf Clausius

The entropy of the universe tends to a maximum.

- Rudolf Clausius

The entropy of an isolated system not in equilibrium will tend to increase over time, approaching a maximum value at equilibrium.

- Rudolf Clausius

The fundamental laws of the universe which correspond to the two fundamental theorems of the mechanical theory of heat. 1. The energy of the univers…

- Rudolf Clausius