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Concerning the Loadstone : of things particularly spoken thereof,
evidently or probably true. AND first, we conceive the earth to be a magnetical body? A magnetical body, we term, not only that which hath a power attractive, but that which, seated in a convenient medium, naturally disposeth itself to one invariable and fixed
? And first, we conceive the earth, &c.] The chapter which begins with this opinion, though containing many errors, is yet characterized by the sagacity and acuteness so often displayed by the author in treating of a complex and difficult subject of science, and also by those philosophic views in which he occasionally anticipated the most profound results attained in the modern investigations of the powers of nature. The remark now immediately before us partakes, in all respects, of the character of the chapter itself. That the earth is “a magnetical body," in the senses in which we apply that term to the magnet itself, and to the metals, iron, nickel, and some others, is a notion for which there is no foundation whatever ; nor have we any reason for supposing that the “polary position" of the earth, or the direction of its axis in space, is produced by magnetism. And further, there is a deep error in philosophy in the fundamental notion of the author, that a magnetical body, as he defines it, naturally “disposeth itself” to one invariable and fixed situation; the fact being, as all the phenomena of magnetism conspire to evince, that magnetized bodies which apparently possess that property are in reality disposed to it, by the influence of a subtle agent permeating them, and the action of which is in some unknown manner connected with an arrangement in space, having a particular relation to the figure and position, and probably to some of the material constituents also of the earth. Supposing it to be true (which at present, however, we have no reason to suppose) that if the whole earth could be violently removed, it would "return unto its polary position again,” that effect would not result from an inherent virtue in the planet itself, but from its being so constituted as to receive and obey the action of the vortical or other motions of the subtle ethereal fluid, in which (from the recent investigations of Encke and others) we now know it to be placed, and by which also we know it to be pervaded : this would cause it to return to its position, much in the same way as a ball held by strings in a particular position returns to that position after displacement, by their action upon it; or, which is a closer representation of the circumstances, as a magnetic needle, after disturbance, returns to its original direction, to the magnetic north and south, by the force of terrestrial magnetism acting upon it.-Br.
situation. And such a magnetical virtue we conceive to be in the globe of the earth, whereby, as unto its natural points and proper terms, it disposeth itself unto the poles ; being so framed, constituted, and ordered unto these points, that those parts which are now at the poles, would not naturally abide unto the equator, nor Greenland remain in the place of Magellanica. And if the whole earth were violently removed, yet would it not forego its primitive points, nor pitch in the east or west, but return unto its polary position again. For, though by compactness or gravity it may acquire the lowest place, and become the centre of the universe,8 yet, that it makes good that point, not varying at all by the accession of bodies upon, or secession thereof from its surface, perturbing the equilibration of either hemisphere (whereby the altitude of the stars might vary), or that it strictly maintains the north and southern points, that neither
upon the motions of the heavens, air, and winds without, large eruptions and divisions of parts within its polary parts, should never incline or veer unto the equator (whereby the latitude of places should also vary), it cannot so well be salved from gravity, as a magnetical verticity. This is, probably, that foundation the wisdom of the Creator hath laid unto the earth; in this sense we may more nearly apprehend, and sensibly make out the expressions of holy scripture, as, Firmavit orbem terræ qui non commovebitur, “ he hath made the round world so sure, that it cannot be moved;"* as when it is said by Job, extendit aquilonem super vacuo, &c., " he stretcheth forth the north
the empty place, and hangeth the earth upon nothing."† And this is the most probable answer unto that great question, “ Whereupon are the foundations of the earth fastened, or who laid the corner-stone thereof?” Had they been acquainted with this principle, Anaxagoras, Socrates, and Democritus, had better made out the ground of this stability; Xenophanes had not been fain to say, the earth
8 and become the centre of the unőverse.] It must be borne in mind that the author was not a convert to the Copernican system of astronomy. His opposite opinions on this science will be observed to pervade all his reasonings, and to tinge all his feelings. VOL. I.
hath no bottom; and Thales Milesius, to make it swim in water.9
Nor is the vigour of this great body included only in itself, or circumferenced by its surface, but diffused at indeterminate distances through the air, water, and all bodies circumjacent; exciting and impregnating magnetical bodies within its surface or without it, and performing, in a secret and invisible way, what we evidently behold effected by the loadstone. For these effluxions penetrate all bodies, and like the species of visible objects are ever ready in the medium, and lay hold on all bodies proportionate or capable of their action; those bodies likewise, being of a congenerous nature, do readily receive the impressions of their motor; and, if not fettered by their gravity, conform themselves to situations wherein they best unite unto their animator. And this will sufficiently appear from the observations that are to follow, which can no better way be made out, than by this we speak of, the magnetical vigour of the earth. Now, whether these effluviums do fly by striated atoms and winding particles, as Renatus des Cartes conceiveth, or glide by streams attracted from either pole and
hemisphere of the earth unto the equator, as Sir Kenelm Digby excellently declareth, it takes not awayề this virtue of the earth ; but more distinctly sets down the gests and progress thereof, and are conceits of emi
9 water.] The first edition continues thus :-“Now whether the earth stand still, or moveth circularly, we may concede this magnetical stability : for although it move, in that conversion the poles and centre may still remain the same, as is conceived in the magnetical bodies of heaven, especially Jupiter and the sun ; which, according to Galileus, Kepler, and Fabricius, are observed to have dinetical motions and certain revolutions about their proper centres ; and though the one in about the space of ten days, the other in less than one, accomplish this revolution, yet do they observe a constant habitude unto their poles, and firme themselves thereon in their gyration.”
1 the magnetical vigour of the earth.] Having stated, in the preceding note, in what sense we are not to regard the earth as a magnet, we may now admit that in the sense of a body permeated by the magnetic fluid (whatever that may be) the earth may be regarded as a great complex magnet, or rather as a collection of substances, many of which, under certain circumstances, are susceptible of the magnetic influence, and display accordingly magnetic phenomena.—Br.
? it takes not away.] Read, “they take not away, &c.” viz. “Neither of these opinions takes away, &c."-Wr.
nent use to salve magnetical phenomena. And, as in astronomy, those hypotheses (though never so strange) are best esteemed which best do salve appearances, so surely in philosophy those principles (though seeming monstrous) may with advantage be embraced, which best confirm experiment, and afford the readiest reason of observation. And truly the doctrine of effluxions, their penetrating natures, their invisible paths, and insuspected effects, are very considerable; for, besides this magnetical one of the earth, several effusions there may be from divers other bodies, which invisibly act their parts at any time, and, perhaps, through any medium; a part of philosophy but yet in discovery, and will
, I fear, prove the last leaf to be turned over in the book of nature.
First, therefore, it is true, and confirmable by every experiment, that steel and good iron never excited by the Ioadstone, discover in themselves a verticity;4 that is, a directive or polary faculty, whereby, conveniently placed, they do septentrionate* at one extreme, and australiset at another. This is manifestable in long and thin plates of steel perforated in the middle and equilibrated; or by an easier way in long wires equiponderate with untwisted silk and soft wax; for, in this manner pendulous, they will cor form themselves meridionally, directing one extreme unt the north, another to the south. The same is also mani fested in steel wires thrust through little spheres or globes of cork and floated on the water, or in naked needles gently let fall thereon ; for, so disposed, they will not rest until they have found out the meridian, and as near as they can, lie parallel unto the axis of the earth; sometimes the eye, sometimes the point, northward in divers needles, but the same point always in most; conforming themselves unto the whole earth, in the same manner as they do unto every loadstone. For, if a needle untouched be hanged above a loadstone, it will convert into a parallel position thereto; for in this situation it can best receive its verticity, and be excited proportionably at both extremes. Now this direction proceeds, not primitively from themselves, but is derivative and contracted from the magnetical effluxions of the earth, which they have winded in their hammering and formation, or else, by long continuance in one position, as we shall declare hereafter.
* Point to the north.
+ Point to the south.
3 And truly the doctrine of effluxions.] The remarks in the passage commencing with these words may be considered to have been made good by the discoveries of the present century, if we regard the notion of “effluxions” to result from an obscure perception of the existence and functions of those ethereal fluids, to the motions of which the united results of modern science lead us to attribute the phenomena of heat, light, electricity, magnetism, &c. It is requisite, however, to observe, that what Browne, as well as some of his predecessors and contemporaries, appears to have supposed to consist of subtle emanations from grosser bodies, must be regarded contrariwise, agreeably to the most profound researches of our time, as the principles from which all ordinary ponderable matter derives its activity—from which it takes all its force and energy.--Br.
4 steel and good iron, &c.] This, in the sense in which the author intends us to understand it, is an error ; unmagnetized iron or steel has no directive power; the experiments apparently alluded to must have been performed with steel plates, wires, and needles, which had, in reality, become magnetic, although they might not have been actually “ excited by the loadstone.” As an observation that the magnetic virtue is possessed by bodies which have not been so excited, it is quite worthy of Browne.-Br.
It is likewise true what is delivered of irons heated in the fire, that they contract a verticity in their refrigeration ;5
5 They contract a verticity, &c.] The statements here made, to the end of the period, are probably true, provided the cooling takes place in a direction corresponding, or nearly corresponding, to that of the dip; but the extent to which they are true, so far as modern experiments afford us the means of verifying them, may be best seen, perhaps, by comparing them with the following observations made by Mr. Barlow, and published in the Encyclopædia Metropolitana, Treatise on Magnetism, & v. 38, 39 :-For certain purposes of research, which it is unnecessary here to state, Mr. Barlow heated in a furnace a bar of soft iron and a bar of cast-iron, nearly of equal dimensions, placing them in an inclined position, in the direction of the dip of the needle, and ascertaining their attractive effect upon the horizontal or common magnetic needle previously to the application of heat. As soon as the bars arrived at a high blood-red heat, they began to exercise an increased power of attraction upon the needle, and in a minute or two this attained its maximum, which was far greater than the attractive power of the bars when cold; the deviation produced by one of them being in the latter case 24° 20', but in the former, 780 30'. In the course of these experiments the following facts were observed, which bear directly upon the passage of our author now before us :—“It should be observed here, that the great attraction produced by the heat did not subside with it, provided the bar remained in its place undis