“The space surrounding a magnet is a magnetic field. If we electrify a piece of sealing-wax by rubbing it, it surrounds itself by a dielectric or electrostatic field, and bodies susceptible to electrostatic forces—such as light pieces of paper—are attracted. The earth is surrounded by a gravitational field, the lines of gravitational force issuing radially from the earth. If a stone falls to the earth, it is due to the stone’s being in the gravitational field of the earth and being acted upon by it.” Again:—“Suppose we have a permanent bar magnet and bring a piece of iron near it. It is attracted, or moved; that is, a force is exerted on it. We bring a piece of copper near the magnet, and nothing happens. We say that the space surrounding the magnet is a _magnetic field_. A _field_, or _field of force_, we define as ‘a condition in space exerting a force on a body susceptible to this field’. Thus, a piece of iron being magnetizable—that is, susceptible to a magnetic field—will be acted upon; a piece of copper, not being magnetizable, shows no action.... To produce a field of force requires energy, and this energy is stored in the space we call the field. Thus we can go further and define the field as ‘_a condition of energy storage in space exerting a force on a body susceptible to this energy_’.” Thales said that the “divine moving power”, the soul of nature, under certain conditions “moves iron”, through the mysterious properties of the lodestone. Modern science, borrowing from Aristotle the term _energia_, substitutes for “soul of nature” the single word _energy_. Aristotle declared that “not capacity, but energy ... is the first principle anterior to and superior to anything else” (_Metaphysics_ xii, 7: cf. also _Physics_ ii, 9, 6). Modern science describes in more precise phrases what _occurs_ when a body susceptible to the influence of the magnet is brought into proximity to a lodestone (magnetite). It gives us a picture of “lines of force” (energy) in a defined “field”. But it tells us no more about what energy _is_ than Thales tells us what his “moving power” is. Dr. Steinmetz tells us that “energy is the only real existing entity, the primary conception, which exists for us because our senses respond to it” (_Op. cit._, Page 23). For Thales the universal “moving power” of nature operates _on_ or _in_ all matter; for the physicist of today the moving power (energy) is matter—man’s perception of matter being the response of his senses to the vibrations of energy. “All sense perceptions are exclusively energy effects,” and “energy is the only real existing entity.”