Note 164 — Chapter IV · CREATION.—THE GENESIS OR BEGINNING.

Energy is now defined as "the power of doing work," that is, the power, in virtue of its position (as a head of water, a raised mass, a coiled spring) or in virtue of its motion (as a falling mass, a current of wind, a projectile), to do work. The first is called Potential, the second Kinetic Energy. Besides these instances of Visible Energy, there is also Invisible Molecular Energy, divided into, (a) the Energy of electricity in motion; (b) the Energy of radiant heat and light; (c) the kinetic Energy of absorbed heat; (d) molecular potential Energy; (e) potential Energy caused by electrical separation; (f) potential Energy caused by chemical separation. Of these different kinds of Energy, the most available for work is Mechanical Energy, or Energy of visible motions and positions; the least available is universal heat, or radiant Energy.