In versoria whose cusps have been rubbed, but not their cross-ends, * the crosses mutually repel one another, but weakly and in proportion to their length. In like versoria the cusps, having been touched by the same * pole of the loadstone, attract the cross-ends with equal strength. In a somewhat long versorium the cross-end is attracted rather * weakly by the cusp of a shorter iron versorium; the cross of the shorter more strongly by the cusp of the longer, because the cross of the longer versorium has a weak verticity, but the cusp has a stronger. The cusp of a longer versorium drives away the cusp of a * shorter one more vehemently than the cusp of the shorter the cusp of the longer, if the one is free upon a pin, and the other is held in the hand; for though both were equally excited by the same loadstone, yet the longer one is stronger at its cusp on account of its greater mass. The Southern end of an iron rod which is not excited attracts * the Northern, and the Northern the Southern; moreover, also the Southern parts repel the Southern, and the Northern the Northern. If magnetick substances are divided or in any way broken in pieces, each part has a Northern and a Southern end. {102} A versorium is moved as far off by a loadstone when an obstacle * is put in the way, as through air and an open medium. Rods rubbed upon the pole of a stone strive after the same pole * and follow it. Therefore Baptista Porta errs when he says, chapter 40[182], "If you put that part to it from which it received its force, it will not endure it, but drives it from it, and draws to it the contrary and opposite part." The principles of turning round and inclining are the same in the case of loadstone to loadstone, of loadstone to iron, of iron also to iron. When magnetick substances which have been separated by force and dissected into parts flow together into a true union and are suitably connected, the body becomes one, and one united virtue, nor have they diverse ends. The separate parts assume two opposite poles, if the division has * not been made along a parallel: if the division has been made along a parallel, they are able to retain one pole in the same site as before. Pieces of iron which have been rubbed and excited by a loadstone are more surely and swiftly seized by a loadstone at fitting ends than such as have not been rubbed. If a spike is set up on the pole of a loadstone, a spike or style * of iron placed on the upper end is strongly cemented to it, and draws away the erect spike from the terrella when motion is made. If to the lower end of the erect spike the end of another spike * is applied, it does not cohære with it, nor do they unite together. As a rod of iron draws away a piece of iron from a terrella, so is it also with a minute loadstone and a lesser terrella, though weaker in strength. [Illustration]