D the forces by which D is taken and conformed, though they are weaker than those which C receives from B. And those iron nails indeed from that contact only, and from the presence of the loadstone even without contact, acquire powers which they retain in their own bodies, as will be demonstrated most clearly in the passage on Direction. For not only whilst the stone is present does the iron assume these powers, and take them, as it were, vicariously from the stone, as Themistius lays down in his 8th book on Physicks. The best iron, when it has been melted down (such is steel), is allured by a loadstone from a greater distance, is raised though of greater weight, is held more firmly, assumes stronger powers than the common and less expensive, because it is cast from a better ore or loadstone, imbued with better powers. But what is made from more impure ore turns out weaker and is moved more feebly. As to Fracastorio's statement that he saw a piece of loadstone draw a loadstone by one of its faces, but not iron; by another face iron, but not loadstone; by another both; which he says is an indication that in one part there is more of the loadstone, in another more of the iron, in another both equally, whence arises that diversity of attraction; it is most incorrect and badly observed on the part of Fracastorio, who did not know how to apply skilfully loadstone to loadstone. A loadstone draws iron and also a loadstone, if both are suitably arranged and free and unrestrained. That is removed more quickly from its position and place which is lighter; for the heavier bodies are in weight, the more they resist; but the lighter both moves itself to meet the heavier and is allured by the other.
CHAP. V.
How the Power dwells in the
Loadstone.
hat a loadstone attracts loadstone, iron and other magnetical bodies, has been shown above in the previous book, and also with what strength the magnetick coition is ordered; but now we must inquire how that vigour is disposed in a magnetick substance. And indeed an analogy must be inferred from a large loadstone. Any magnetick substance joins itself with a loadstone strongly, if the loadstone itself is strong; but more weakly, when it is somewhat imperfect or has been weakened by some flaw. A loadstone does not draw iron equally well with every part; or a magnetick substance does not approach every part of a loadstone alike; because a loadstone has its points, that is its true poles, in which an exceptional virtue excels. Parts nearer the pole are stronger
