simply prepared by fire, and freed from their refuse humour; and as by the loadstone so also by the earth herself they are drawn and controlled magnetically, in a way different from all other bodies; and by that inherent force settle themselves according to the orderly arrangement and fabric of the universe and of the Earth, as will appear {44} later. Thus every part of the earth which is removed from it exhibits by sure experiments every impulse of the magnetick nature; by its various motions it observes the globe of the earth and the principle common to both. [Illustration] * * * * * {45} [Illustration] BOOK SECOND. _CHAP. I._ ON MAGNETICK Motions. Divers things concerning opinions about the magnet-stone, and its variety, concerning its poles and its known faculties, concerning iron, concerning the properties of iron, concerning a magnetick substance common to both of these and to the earth itself, have been spoken briefly by us in the former book. There remain the magnetical motions, and their fuller philosophy, shown and demonstrated. These motions are incitements of homogeneal parts either among themselves or toward the primary conformation of the whole earth. Aristotle admits only two simple motions of his elements, from the centre and toward the centre; of light ones upward, heavy ones downward; so that in the earth there exists one motion only of all its parts towards the centre of the world,--a rude and inert precipitation. But what of it is light, and how wrongly it is inferred by the Peripateticks from the simple motion of the elements, and also what is its heavy part, we will discuss elsewhere. But now our inquiry must be into the causes of other motions, depending on its true form, which we have plainly seen in our magnetick bodies; and these we have seen to be present in the earth and in all its homogenic parts also. We have noticed that they harmonize with the earth, and are bound up with its forces. Five movements[106] or differences of motions are then observed by us: Coition (commonly called attraction), the {46} incitement to magnetick union; Direction towards the poles of the earth, and the verticity and continuance of the earth towards the determinate poles of the world; Variation, a deflexion from the meridian, which we call a perverted movement; Declination, a descent of the magnetick pole below the horizon; and circular motion, or Revolution. Concerning all these we shall discuss separately, and how they all proceed from a nature tending to aggregation, either by verticity or by volubility. Jofrancus Offusius[107] makes out different magnetick motions; a first toward a centre; a second toward a pole at seventy-seven degrees; a third toward iron; a fourth toward loadstone. The first is not always to a centre, but exists only at the poles in a straight course toward the centre, if the motion is magnetick; otherwise it is only motion of matter toward its own mass and toward the globe.