Magnetism

^33-b Reactions are either:

1. Sympathetic

This is:

• verticity

  • a curve
  • directed to a certain point of a globe around its center

• attraction

  • a straight line
  • directed to a certain thing

Verticity is found in the magnet and in most things, though in unequal degree.

For some are more permeable to aether than others, as their pores are proportioned to its motion.

The magnet and iron excel the rest, owing to their innate love of cold and their long position in the mine towards the poles.

But this love of the north cannot suffice for a direction so constant and so universal unless a universal cause everywhere present – that is, the circulation of the aether – comes into play.

Verticity, therefore, or the property by which bodies establish their extremities balanced between the poles of our globe, seems to arise from the motion of the aether from east to west (above, §9, 10); which prevents their extremities from being turned directly or obliquely towards east or west; north and south therefore remain. But to examine the particular phenomena that present themselves in this matter of verticity is foreign to our present brevity.

2. Antipathetic

34 Nevertheless, I cannot omit this: that all consistency or cohesion of bodies arises from motion. Bodies at rest in their whole arise from the motion of their parts returning upon themselves (lest they fly away), that is, circular motion, or rather, due to compression, sometimes elliptical, according to the abstract theory of motion; hence bodies so exercise that motion that they may do so most conveniently. They can do so most conveniently in that direction in which the motion of the aether does not obstruct them – therefore towards the poles of the terrestrial globe, because the motion of the aether is not towards the poles but around the poles. Moreover, the motion of the parts thus constitutes its own poles for the body, and antipathies of different poles and of poles affected by other poles. The poles of a magnet are so called because the poles of the earth…

[34] 33. Thus, by means of rare, sparse, and similar congregating-together. On the contrary, for cold, because it tightens, it arises from a powerful and straight motion, but thick, whence dulling, not penetrating, and therefore not dissolving, but tightening. However, hard or densely-compacted things are mostly cold, as are marble, metal, and mercury, because their pores are narrow, through which air or wind passes: whence the cooling wind is condensed, tightened, gathered together, completely in the same way as in cities, alleys that very often are accustomed to have great cold. I add one thing for greater clarity, that the impression of heat and cold differ, as if in that same shaft, a puncture made by a very sharp point, is driven by a rough wooden shaft to penetrate. It is not of this time to enter into other, countless varieties of the sense of touch, when most arise from surface [phenomena] rather than the central composition of things, however, we will touch upon the sources to be explained below, Section 59. Let us pass over to the extraordinary or physical motions of bodies, which arise from weight or mechanical principles, as they are not perceived by sense.

33. These, in passing, I divide into sympathetic and antipathetic. The sympathetic are vertical and attractive. This is in a circular line, this in a straight line; this to a certain point of the globe, around the center of the sum, this to a certain matter: Vertical is not only in a magnet, but in most other things, although of unequal degree, for some are more pervious to the ether than others, and proportionate to their pores, to its motion. nat…

[35] nata sunt, and iron more than others, with the innate love of cold, during the course of which in the mine it is positioned toward the poles. But this love of the north wind, in its direction so constant, so universal, unless a universal ubiquitous cause is present, that is, the etherial circulation supervenes, cannot suffice: Therefore, the vertical, or so to speak, balanced between the poles of our globe, making its extreme ends consistent, seems to come about from the motion of the ether from east to west above Sections 9, 10: which prohibits it from pointing to the East or West, but that it must necessarily turn itself toward the North and South. But those things that offer particular phenomena in this matter of verticality, it is foreign to our present brevity to examine.

34. However, I cannot omit this, when all consistency or cohesion of bodies arises from motion, of bodies resting as a whole, that it arises from the motion of parts returning into themselves (lest they should flee) that is, in a circular motion, or rather on account of confinement, sometimes elliptical, through the abstract theory of motion; hence bodies exercise that motion so that they can most conveniently; but they can most conveniently [do so] in that direction in which the etheral motion does not obstruct, therefore toward the poles of the globe, not that the etheral motion is towards the poles, but around the poles. Furthermore, the motion of the parts establishes the poles appropriate for the bodies themselves, of the poles of the diverse and of the poles of the affected [ones], the antipathies. They are called magnetic poles because they [are] to the poles… terr..

³⁴ Nevertheless, I cannot omit this**, since all consistency or cohesion of bodies must arise from motion.

The consistency of bodies resting as a whole will arise from the motion of the parts, returning into themselves (lest they fly away), that is, circular, or rather by constriction, sometimes elliptical, through the abstract Theory of motion.

Hence, bodies exercise that motion in the way they can most conveniently; they can do so most conveniently in that region where the motion of the aether does not obstruct, therefore toward the poles of the terrestrial globe, because the motion of the aether is not toward the poles, but around the poles. Furthermore, this motion of the parts constitutes its own proper poles for the body, and the antipathies of different poles and of poles affected by poles. The poles of a magnet are so called because [they correspond to] the poles of the earth…

[36]

…they correspond to [the poles] of the earth, although the internal motions of the magnet are not in the axis, but rather in the equator[cite: 1]. Because, however, that motion of the parts is not parallel, but occurs in circles intersecting at the pole in the manner of meridians, hence arises a new similarity with the poles of the earth[cite: 1].

Rotate a sphere around an axis perpendicular to the horizon.

• Let it touch at the equator the equator of another similarly rotatable sphere, orbit, or ring.

It will impress its own motion upon it, but into the opposite region[cite: 1]. For if the former moves from the east through the north to the west, the latter will move from the east through the south to the west, or from the west through the north to the east[cite: 1].

But what is contrary in regions is not so in motion, for if the spheres or rings are transferred with a changed position while the motion is retained, there will be a convenience in the regions; the motions will obstruct each other because the retained point of one touches the opposite point of the other, for if the opposite of both is taken, the obstacle will cease[cite: 1].

In a magnet, however, as many rings must be imagined as there are meridians—that is, infinite to the sense—all of which intersect at one point of motion or friction[cite: 1]. This is no more difficult than rays of light passing through the same opening without confusion[cite: 1]. Furthermore, by this friction, motion is transferred; and the position which, for example’s sake, suits the northern part, is acquired there as well; and because the circles intersect again at the opposite point of the receiving…[cite: 1]

[37]

…point, a position is acquired there as well, which it has in the opposite point from the giving point, namely the southern[cite: 1]. But these things are in friction: otherwise, similar poles repel each other; the reason is that the position of one or the other is preternatural[cite: 1].

Furthermore, in the terrestrial globe itself, it is credible that there are magnetic motions—the more subtle parts of Light rejected by a stronger motion under the Tropics toward the poles through the meridians (which seems not foreign even to the opinion of the most celebrated Kircher)[cite: 1]. Magnet and iron, the genuine offspring of the earth, have received the impression of this motion above all others.

But what is the reason for magnetic inclination, by which a needle shows the elevation of the pole by being raised or depressed?

None other than that any magnet and any needle are to be considered as if rubbed against the pole of the earth, just as iron filings placed upon a magnet incline toward the point closer to the other pole, but rest or vacillate when placed in the middle[cite: 1].

Whence, according to Kircher, once the Lineam ventum [wind line] is passed, the magnetic arc wavers with innumerable oscillations[cite: 1].

But as for what he adds further—that beyond the Line, the needle no longer shows the elevation of the pole with its inclination—this I do not yet sufficiently understand.

The reason for the fact itself must be investigated more thoroughly, so that the cause can be established; since it is certain that the pole of a magnet which looks toward our pole of the earth on this side of the line, also looks toward it across the line, as they say.

But this also is difficult: if the arctic pole of a Terrella [little earth/spherical magnet] is placed upon cork and balanced, [it looks toward] the same meridian everywhere…

[38]

…the terrella [spherical magnet] turns toward the pole of the earth; but in such a way that if the antarctic pole is applied, the point which before was oriental becomes occidental.

It would remain to be tested beyond the [equator] line whether, by the application of the arctic or antarctic [pole], that which is here the oriental point also becomes the oriental point there; just as that also, which seems to depend on the same reasoning, [namely] whether iron hanging perpendicularly for a long time—which they affirm here turns its lower part toward the arctic pole if balanced—would turn that same part toward the antarctic if it hung across the line[cite: 1]. Since these things have not been explored, I think they must be judged by the reasoning found[cite: 1].

However, since there is such a regular and strong motion in a magnet, it is no wonder that the air, which is driven against it by its own gravity, is rejected by it, and through its mediation motion is communicated to the iron, which, being similarly disposed, easily receives the impression.

This is established not only by a taut string communicating sound through the air to another similarly taut string, but also by that experiment of a glass whose sound has been explored by a pulse: if a similar sound is produced by someone standing nearby, it resonates even without being touched.

Therefore, every action of a magnet upon distant iron will also be a certain insensible friction[cite: 1]. A magnet moves the iron, but why does it move it toward itself, or pull it? Because the iron is filled or perfected by these radiations, as an alkali [is perfected] by a proportioned acid: therefore, to absorb these more and more, it approaches and thus nears the source itself, or the magnet.

[39]

35. Therefore, the attraction of iron by a magnet is easily explained, once the traction of Amber [Electricity] is explained; for they differ only in subtlety, whence the attraction of a magnet needs no friction (although it is helped by polishing) and penetrates thick bodies[cite: 1].

Electrical attraction, in my judgment, can be easily explained once the attraction is explained by which smoke attracts fire[cite: 1]. For, as is known even to boys, if a smoking candle is placed under a burning one so that the smoke of the former reaches the flame of the latter, the fire descends through the “stairs,” as it were, of the smoke and relights the recently extinguished candle; which can also be the cause of lightning[cite: 1].

Of this Electrical and smoky attraction, this is the only difference: that the former is felt by its own form, the latter only by its effect[cite: 1]. The descent of fire through smoke seems to occur in the same way as the ascent of water through a pump, or rather the rushing of water or air into an evacuated receiver[cite: 1]. For the smoke, exhausted by too many explosions, seeks to reabsorb what it finds already collected in the fire: for flame is nothing other than ignited smoke, and smoke is like a river of volatile parts (as ash is the sediment of fixed ones) that have been exhausted; whence that [substance] is volatile alkali in soot, but fixed in ash: but of these things [I shall speak] more exquisitely elsewhere[cite: 1].