The first chapter embraces what we know regarding atoms, and gives also a definition of Energy. The various forces and energies of nature are thereafter enumerated, and the law of Conservation is stated. Then follow the various transmutations of Energy, according to a list, for which the author is indebted to Prof. Tait. The fifth chapter gives a short historical sketch of the subject, ending with the law of Dissipation; while the sixth and last chapter gives some account of the position of living beings in this universe of Energy.

The Owens College, Manchester,

August, 1873.

Principle of Virtual Velocities (What we gain in

power we lose in space).

First clearly defined by Galileo

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What Friction and Percussion do.

Friction converts Energy into a less useful

Form

Percussion does the same

When Friction and Percussion destroy

Motion, Heat appears

Heat a species of Motion

Davy's Experiments

Rumford's Experiments

Argument derived from these

Heat a Backward and Forward Motion.

A Heated Substance not in Motion as a whole

Analogy between Heat and Sound

Mechanical Equivalent of Heat.