Chap. xvii.
That the globe of the earth is magnetick, & a magnet; & how in our hands the magnet stone has all the primary forces of the earth, while the earth by the same powers remains constant in a fixed direction in the universe.

P rior to bringing forward the causes of magnetical motions, & laying open the proofs of things hidden for so many ages, & our experiments (the true foundations of terrestrial philosophy), we have to establish & present to the view of the learned our New & unheard of doctrine about the earth; and this, when argued by us on the grounds of its probability, with subsequent experiments & proofs, will be as certainly assured as anything in philosophy ever has been considered & confirmed by clever arguments or mathematical proofs. The terrene mass, which together with the vasty ocean produces the sphærick figure & constitutes our globe, being of a firm & constant substance, is not easily changed, does not wander about, & fluctuate with uncertain motions, like the seas, & flowing waves: but holds all its volume of moisture in certain beds & bounds, & as it were in oft-met veins, that it may be the less diffused & dissipated at random. Yet the solid magnitude of the earth prevails & reigns supreme in the nature of our globe. Water, however, is attached to it, & as an appendage only, & a flux emanating from it; whose force from the beginning is conjoined with the earth through its smallest parts, and is innate in its substance. This moisture the earth as it grows hot throws off freely when it is of the greatest possible service in the generation of things. But the thews and dominant stuff of the globe is that terrene body which far exceeds in quantity all the volume of flowing streams and open waters (whatever vulgar philosophers may dream of the magnitudes and proportions of their elements), and which takes up most of the whole globe and almost fills it internally, and by itself almost suffices to endow it with sphærick shape. For the seas only fill certain not very deep or profound hollows, since they rarely go down to a depth of a mile and generally do not exceed a hundred or 50 fathoms. For so it is ascertained by the observations of seamen when by the plumb-line and sinker its abysms are explored with the nautical sounder; which depths relatively to the dimensions of the globe, do not much deform its globular shape. Small then appears to be that portion of the real earth that ever emerges to be seen by man, or is turned up; since we cannot penetrate deeper into its bowels, further than the wreckage of its outer efflorescence, either by reason of the waters which gush up in deep workings, as through veins, or for want of a wholesome air to support life in the miners, or on account of the vast cost that would be incurred in pumping out such huge workings103, and many other difficulties; so that to have gone down to a depth of four hundred, or (which is of rarest occurrence) of five hundred fathoms104 as in a few mines, appears to all a stupendous undertaking. But it is easy to understand how minute, how almost negligibly small a portion that 500 fathoms is of the earth's diameter, which is 6,872 miles. It is then parts only of the earth's circumference and of its prominences that are perceived by us with our senses; and these in all regions appear to us to be either loamy, or clayey, or sandy, or full of various soils, or marls: or lots of stones or gravel meet us, or beds of salt, or a metallick lode, and metals in abundance. In the sea and in deep waters, however, either reefs, and huge boulders, or smaller stones, or sands, or mud are found by mariners as they sound the depths. Nowhere does the Aristotelian element of earth come to light; and the Peripateticks are the sport of their own vain dreams about elements. Yet the lower bulk of the earth and the inward parts of the globe consist of such bodies; for they could not have existed, unless they had been related to and exposed to the air and water, and to the light and influences of the heavenly bodies, in like manner as they are generated, and pass into many dissimilar forms of things, and are changed by a perpetual law of succession. Yet the interior parts imitate them, and betake themselves to their own source, on the principle of terrene matter, albeit they have lost the first qualities and the natural terrene form, and are borne towards the earth's centre, and cohære with the globe of the earth, from which they cannot be wrenched asunder except by force. But the loadstone and all magneticks, not the stone only, but every magnetick homogenic substance, would seem to contain the virtue of the earth's core and of its inmost bowels, and to hold within itself and to have conceived that which is the secret and inward principle of its substance; and it possesses the actions peculiar to the globe of attracting, directing, disposing, rotating, stationing itself in the universe, according to the rule of the whole, and it contains and regulates the dominant powers of the globe; which are the chief tokens and proofs of a certain distinguishing combination, and of a nature most thoroughly conjoint. For if among actual bodies one sees something move and breathe, and experience sensations, and be inclined and impelled by reason, will one not, knowing and seeing this, conclude that it is a man or something rather like a man, than that it is a stone or a stick? The loadstone far excels all other bodies known to us in virtues and properties pertaining to the common mother: but those properties have been far too little understood or realized by philosophers: for to its body bodies magnetical rush in from all sides and cleave to it, as we see them do in the case of the earth. It has poles, not mathematical points, but natural termini of force excelling in primary efficiency by the co-operation of the whole: and there are poles in like manner in the earth which our forefathers sought ever in the sky: it has an æquator, a natural dividing line between the two poles, just as the earth has: for of all lines drawn by the mathematicians on the terrestrial globe, the æquator is the natural boundary, and is not, as will hereafter appear, merely a mathematical circle. It, like the earth, acquires Direction and stabilit............