Chap. IX. “The Northern part of the magnet attracts the Southern and the reverse, as has been shown; in which attraction the magnet is an ‘agent’ of greater power while the ‘patient’ (_i. e._ the other which is acted upon) is, of weaker.” This is proved by taking a loadstone--marking it, for instance, AD--dividing, separating it into two parts, and placing one part (the Northern, marked A, called the “agent”) into water so that it will float. It will turn “to the North, as before, for the division does not deprive the parts of the stone of their properties, if it be homogeneous.” The other part (the Southern, marked D, called the “patient”) is next to be floated in a similar manner. When this is done, the other ends of the two stones should be marked respectively B and C. It will then be observed that “if the same parts are again brought near each other, one will attract the other, so that they will be joined together again at B and C where the division took place. Whence it is that they become one body with the same natural propensity as at first. The proof of this is that if they are joined together they will possess the same oppositions (opposite poles) they first contained. The ‘agent,’ therefore, as you will see by experiment, intends to unite its ‘patient’ to itself, and this takes place on account of the similitude between them.... And, in the same way, it will happen that if A is joined with D, the two lines will become one, by virtue of that very attraction, in this order CD--AB ... there will then remain the identity of the extreme parts as at first, before they were reunited, for C will be the North point and B the South point, as B and C were before.... It is therefore evident, from these observations, why the Southern parts do attract the Northern, and the reverse, and why the attraction of the South by the South, and the North by the North, is not according to Nature.”