Loadstone seems to attract Loadstone when in natural
position: but repels it when in a contrary one, and brings
_it back to order_.
First of all we must declare, in familiar language, what are the apparent
and common virtues of the stone; afterward numerous subtilities, hitherto
abstruse and unknown, hidden in obscurity, are to be laid open, and the
causes of all these (by the unlocking of nature's secrets) made evident, in
their place, by fitting terms and devices. It is trite and commonplace that
loadstone draws iron; in the same way too does loadstone attract loadstone.
Place the stone which you have seen to have poles clearly distinguished,
and marked austral and boreal, in its vessel so as to float; and let the
poles be rightly arranged with respect to the plane of the horizon, or, at
any rate not much raised or awry: hold in your hand another stone the poles
of which are also known; in {16} such a way that its austral pole may be
toward the boreal pole of the one that is swimming, and near it, sideways:
for the floating stone forthwith follows the other stone (provided it be
within its force and dominion) and does not leave off nor forsake it until
it adhæres; unless by withdrawing your hand, you cautiously avoid contact.
In like manner if you set the boreal pole of the one you hold in your hand
opposite the austral pole of the swimming stone, they rush together and
follow each other in turn. For contrary poles allure contrary. If, however,
you apply in the same way the northern to the northern, and the austral to
the austral pole, the one stone puts the other to flight, and it turns
aside as though a pilot were pulling at the helm and it makes sail in the
opposite ward as one that ploughs the sea, and neither stands anywhere, nor
halts, if the other is in pursuit. For stone disposeth stone; the one turns
the other around, reduces it to range, and brings it back to harmony with
itself. When, however, they come together and are conjoined according to
the order of nature, they cohære firmly mutually. For instance, if you were
to set the boreal pole of that stone which is in your hand before the
tropic of Capricorn of a round floating loadstone (for it will be well to
mark out on the round stone, that is the terrella, the mathematical circles
as we do on a globe itself), or before any point between the æquator and
the austral pole; at once the swimming stone revolves, and so arranges
itself that its austral pole touches the other's boreal pole, and forms a
close union with it. In the same way, again, at the other side of the
æquator, with the opposite poles, you may produce similar results; and thus
by this art and subtilty we exhibit attraction, repulsion, and circular
motion for attaining a position of agreement and for declining hostile
encounters. Moreover 'tis in one and the same stone that we are thus able
to demonstrate all these things and also how the same part of one stone may
on division become either boreal or austral. Let A D be an oblong stone, in
which A is the northern, D the southern pole; cut this into two equal
parts, then set part A in its vessel on the water[67], so as to float.
[Illustration]
{17} And you will then see[68] that A the northern point will turn to the
south, as before; in like manner also the point D will move to the north,
in the divided stone, as in the whole one. Whereas, of the parts B and C,
which were before continuous, and are now divided, the one is southern B,
the other northern C. B draws C, desirous to be united, and to be brought
back into its pristine continuity: for these which are now two stones were
formed out of one: and for this cause C of the one turning itself to B of
the other, they mutually attract each other, and when freed from obstacles
and relieved of their own weight, as upon the surface of water, they run
together and are conjoined. But if you direct the part or point A to C in
the other stone, the one repels or turns away from the other: for so were
nature perverted, and the form of the stone perturbed, a form that strictly
keeps the laws which it imposed upon bodies: hence, when all is not rightly
ordered according to nature, comes the flight of one from the other's
perverse position and from the discord, for nature does not allow of an
unjust and inequitable peace, or compromise: but wages war and exerts force
to make bodies acquiesce well and justly. Rightly arranged, therefore,
these mutually attract each other; that is, both stones, the stronger as
well as the weaker, run together, and with their whole forces tend to
unity, a fact that is evident in all magnets, not in the Æthiopian only, as
Pliny supposed. The Æthiopian magnets if they be powerful, like those
brought from China, because all strong ones show the effect more quickly
and more plainly, attract more strongly in the parts nearest the pole, and
turn about until pole looks directly at pole. The pole of a stone more
persistently attracts and more rapidly seizes the corresponding part (which
they term the adverse part) of another stone; for instance, North pulls
South; just so it also summons iron with more vehemence, and the iron
cleaves to it more firmly whether it have been previously excited by the
magnet, or is untouched. For thus, not without reason hath it been ordained
by nature, that the parts nearer to the pole should more firmly attract:
but that at the pole itself should be the seat, the throne, as it were, of
a consummate and splendid virtue, to which magnetical bodies on being
brought are more vehemently attracted, and from which they are with utmost
difficulty dislodged. So the poles are the parts which more particularly
spurn and thrust away things strange and alien perversely set beside them.
* * * * *
{18} CHAP. VI.
Loadstone attracts the ore of iron, as well as iron
_proper, smelted and wrought_.
Principal and manifest among the virtues of the * magnet, so much and so
anciently commended, is the attraction of iron; for Plato states that the
magnet, so named by Euripides, allures iron, and that it not only draws
iron rings but also indues the rings with power to do the same as the
stone; to wit, draw other rings, so that sometimes a long chain of iron
objects, nails or rings is formed, some hanging from others. The best iron
(like that which is called _acies_ from its use, or _chalybs_ from the
country of the Chalybes) is best and strongly drawn by a powerful
loadstone; whereas the less good sort, which is impure, rusty, and not
thoroughly purged from dross, and not wrought in second furnaces, is more
feebly drawn; and yet more weakly when covered and defiled with thick,
greasy, and sluggish humours. It also draws ores of iron, those that are
rich and of iron colour; the poorer and not so productive ores it does not
attract, except they be prepared with some art. A loadstone loses some
attractive virtue, and, as it were, pines away with age, if exposed too
long to the open air instead of being laid in a case with filings or scales
of iron. Whence it should be buried in such materials; for there is nothing
that plainly resists this exhaustless virtue which does not destroy the
form of the body, or corrode it; not even if a thousand adamants were
conjoined. Nor do I consider that there is any such thing as the
Theamedes[69], or that it has a power opposite to that of the loadstone.
Although Pliny, that eminent man and prince of compilers (for it is what
others had seen and discovered, not always or mainly his own observations,
that he has handed down to posterity) has copied from others the fable now
made familiar by repetition: That in India there are two mountains near the
river Indus; the nature of one being to hold fast all that is iron, for it
consists of loadstone; the other's nature being to repel it, for it
consists of the Theamedes. Thus if one had iron nails in one's boots, one
could not tear away one's foot on the one mountain, nor stand still on the
other. Albertus Magnus writes that a loadstone had been found in his day
which with one part drew to itself iron, and repelled it with its other
end; but Albertus observed the facts badly; for every loadstone attracts
with one end iron that has been touched with a loadstone, and drives it
away with the other; and draws iron that been touched with a loadstone more
powerfully than iron that has not been so touched.
* * * * *
{19} CHAP. VII.
What Iron is, and of what substance,
_and its uses._
For that now we have declared the origin and nature of the loadstone, we
think it necessary first to add a history of iron and to indicate the
hitherto unknown forces of iron, before this our discourse goes on to the
explanation of magnetick difficulties and demonstrations, and to deal with
the coitions and harmonies of loadstone with iron. Iron is by all reckoned
in the class of metals, and is a metal livid in colour, very hard, glows
red-hot before it melts, being most difficult of fusion, is beaten out
under the hammer, and is very resonant. Chemists say that if a bed of fixed
earthy sulphur be combined with fixed earthy quicksilver, and the two
together are neither pure white but of a livid whiteness, if the sulphur
prevail, iron is formed. For these stern masters of metals who by many
inventions twisting them about, pound, calcine, dissolve, sublime, and
precipitate, decide that this metal, both on account of the earthy sulphur
and of the earthy mercury, is more truly a son of the earth than any other;
they do not even think gold or silver, lead, tin, or copper itself so
earthy; for that reason it is not smelted except in the hottest furnaces,
with bellows; and when thus fused, on having again grown hard it is not
melted again without heavy labour; but its slag with the utmost difficulty.
It is the hardest of metals, subduing and breaking all things, by reason of
the strong concretion of the more earthy matter. Wherefore we shall better
understand what iron is, when we shall declare what are the causes and
substance of metals, in a different way from those who before our time have
considered them. Aristotle takes the material of the metals to be vapour.
The chemists in chorus pronounce their actual elements to be sulphur and
quicksilver. Gilgil Mauritanus gives it as ashes moistened with water.
Georgius Agricola makes it out to be water and earth mixed; nor, to be
sure, is there any difference between his opinion and the position taken by
Mauritanus. But ours is that metals arise and effloresce at the summits of
the earth's globe, being distinguished each by its own form, like some of
the other substances dug out of it, and all bodies around us. The earth's
globe does not consist of ashes or inert dust. Nor is fresh water an
element, but a more simple consistency of evaporated fluids of the earth.
Unctuous bodies, fresh water devoid of properties, quicksilver and sulphur,
none of these are principia of metals: these latter, {20} things are the
results of a different nature, they are neither constant nor antecedent in
the course of the generation of metals. The earth emits various humours,
not begotten of water nor of dry earth, nor from mixtures of these, but
from the substance of the earth itself: these humours are not distinguished
by contrary qualities or substance, nor is the earth a simple substance, as
the Peripateticks dream. The humours proceed from vapours sublimated from
great depths; all waters are extracts and, as it were, exudations from the
earth. Rightly then in some measure does Aristotle make out the matter of
metals to be that exhalation which in continuance thickens in the lodes of
certain soils: for the vapours are condensed in places which are less hot
than the spot whence they issued, and by help of the nature of the soils
and mountains, as in a womb, they are at fitting seasons congealed and
changed into metals: but it is not they alone which form ores, but they
flow into and enter a more solid material, and so form metals. So when this
concreted matter has settled down in more temperate beds, it begins to take
shape in those tepid places, just as seed in the warm womb, or as the
embryo acquires growth: sometimes the vapour conjoins with suitable matter
alone: hence some metals are occasionally though rarely dug up native, and
come into existence perfect without smelting: but other vapours which are
mixed with alien soils require smelting in the way that the ores of all
metals are treated, which are rid of all their dross by the force of fires,
and being fused flow out metallick, and are separated from earthy
impurities but not from the true substance of the earth. But in so far as
that it becomes gold, or silver, or copper, or any other of the existing
metals, this does not happen from the quantity or proportion of material,
nor from any forces of matter, as the Chemists fondly imagine; but when the
beds and region concur fitly with the material, the metals assume forms
from the universal nature by which they are perfected; in the same manner
as all the other minerals, plants, and animals whatever: otherwise the
species of metals would be vague and undefined, which are even now turned
up in such scanty numbers that scarce ten kinds are known. Why, however,
nature has been so stingy as regards the number of metals, or why there
should be as many as are known to man, it is not easy to explain; though
the simple-minded and raving Astrologers refer the metals each to its own
planet. But there is no agreement of the metals with the planets, nor of
the planets with the metals, either in numbers or in properties. For what
connexion is there of iron with Mars? unless it be that from the former
numerous instruments, particularly swords and engines of war, are
fashioned. What has copper to do with Venus? or how does tin, or how does
spelter correspond with Jupiter? They should rather be dedicated to Venus.
But this is old wives' talk. Vapour is then a remote cause in the
generation of the metals; the fluid condensed from {21} vapours is a more
proximate one, like the blood and semen in the generation of animals. But
those vapours and juices from vapours pass for the most part into bodies
and change them into marcasites and are carried into lodes (for we have
numerous cases of wood so transmuted), the fitting matrices of bodies,
where they are formed as metals. They enter most often into the truer and
more homogeneal substance of the globe, and in the process of time a vein
of iron results; loadstone is also produced, which is nought else than a
noble kind of iron ore: and for this reason, and on account of its
substance being singular, alien from all other metals, nature very rarely,
if ever, mixes with iron any other metal, while the other metals are very
often minutely mixed, and are produced together. Now when that vapour or
those juices happen to meet, in fitting matrices, with efflorescences
deformed from the earth's homogenic substance, and with divers precipitates
(the forms working thereto), the remainder of the metals are generated (a
specifick nature affecting the properties in that place). For the hidden
primordial elements of metals and stones lie concealed in the earth, as
those of herbs and plants do in its outer crust. For the soil dug out of a
deep well, where would seem to be no suspicion of a conception of seed,
when placed on a very high tower, produces, by the incubation of sun and
sky, green herbage and unbidden weeds; and those of the kind which grow
spontaneously in that region, for each region produces its own herbs and
plants, also its own metals.
_[70]Here corn exults, and there the grape is glad,_
_Here trees and grass unbidden verdure add._
_So mark how Tmolus yields his saffrone store,_
_But ivory is the gift of Indian shore;_
_With incense soft the softer Shebans deal;_
_The stark Chalybeans' element is steel:_
_With acrid castor reek the Pontic wares,_
_Epirus wins the palm of Elian mares._
But what the Chemists (as Geber, and others) call fixed earthy sulphur in
iron is nothing else than the homogenic earth-substance concreted by its
own humour, amalgamated with a double fluid: a metallick humour is inserted
along with a small quantity of the substance of the earth not devoid of
humour. Wherefore the common saying that in gold there is pure earth, but
in iron mostly impure, is wrong; as though there were indeed such a thing
as natural earth, and that the globe itself were (by some unknown process
of refining) depurate. In iron, especially in the best iron, there is earth
in its own nature true and genuine; in the other metals there is not so
much earth as that in place of earth and precipitates there are
consolidated and (so to speak) fixed salts, which are efflorescences of the
globe, and which differ also greatly {22} in firmness and consistency: In
the mines their force rises up along with a twofold humour from the
exhalations, they solidify in the underground spaces into metallic veins:
so too they are also connate by virtue of their place and of the
surrounding bodies, in natural matrices, and take on their specific forms.
Of the various constitutions of loadstones and their diverse substances,
colours, and virtues, mention has been made before: but, now having stated
the cause and origin of metals, we have to examine ferruginous matter not
as it is in the smelted metal, but as that from which the metal is refined.
Quasi-pure iron is found of its proper colour and in its own lodes; still,
not as it will presently be, nor as adapted for its various uses. It is
sometimes dug up covered with white silex or with other stones. It is often
the same in river sand, as in Noricum. A nearly pure ore of iron is now
often dug up in Ireland, which the smiths, without the labours of furnaces,
hammer out in the smithy into iron implements. In France iron is very
commonly smelted out of a liver-coloured stone, in which are glittering
scales; the same kind[71] without the scales is found in England, which
also they use for craftsmen's ruddle[72]. In Sussex in England[73] is a
rich dusky ore and also one of a pale ashen hue, both of which on being
dried for a time, or kept in moderate fires, presently acquire a
liver-colour; here also is found a dusky ore square-shaped with a black
rind of greater hardness. An ore having the appearance of liver is often
variously intermingled with other stones: as also with the perfect
loadstone which yields the best of iron. There is also a rusty ore of iron,
one of a leaden hue tending to black, one quite black, or black mixed with
true cobalt: there is another sort mixed either with pyrites, or with
sterile plumbago. One kind is also like jet, another like bloodstone. The
emery used by armourers, and by glaziers for glass-cutting, called amongst
the English Emerelstone, by the Germans Smeargel, is ferruginous; albeit
iron is extracted from it with difficulty, yet it attracts the versorium.
It is now and then found in deep iron and silver diggings. Thomas Erastus
says he had heard from a certain learned man of iron ores, of the colour of
iron, but quite soft and fatty, which can be smoothed with the fingers like
butter, out of which excellent iron can be smelted: somewhat the same we
have seen found in England, having the aspect of Spanish soap. Besides the
numberless kinds of stony ores, iron is extracted from clay, from clayey
earth, from ochre, from a rusty matter deposited from chalybeate waters; In
England iron is copiously extracted in furnaces often from sandy and clayey
stones which appear to contain iron not more than sand, marl, or any other
clay soils contain it. Thus in Aristotle's book _De Mirabilibus
Auscultationibus_[74], "There is said" (he states) "to be a peculiar
formation of Chalybean and Misenian iron, for instance the sort collected
from river gravel; some say {23} that after being simply washed it is
smelted in the furnace; others declare that it and the sediment which
subsides after several washings are cast in and purified together by the
fire; with the addition of the stone pyrimachus which is found there in
abundance." Thus do numerous sorts of things contain in their various
substances notably and abundantly this element of iron and earth. However,
there are many stones, and very common ones, found in every soil, also
earths, and various and mixed materials, which do not hold rich substances,
but yet have their own iron elements, and yield them to skilfully-made
fires, yet which are left aside by metallick men because they are less
profitable; while other soils give some show of a ferruginous nature, yet
(being very barren) are hardly ever smelted down into iron; and being
neglected are not generally known. Manufactured irons differ very greatly
amongst themselves. For one kind is tenacious in its nature, and this is
the best; one is of medium quality: another is brittle, and this is the
worst. Sometimes the iron, by reason of the excellency of the ore, is
wrought into steel, as to-day in Noricum. From the finest iron, too, well
wrought and purged from all dross, or by being plunged in water after
heating, there issues what the Greeks call [Greek: stomôma]; the Latins
_acies;_ others _aciarium,_ such as was at times called Syrian, Parthian,
Noric, Comese, Spanish; elsewhere it is named from the water in which it is
so often plunged, as at Como in Italy[75], Bambola and Tarazona in Spain.
_Acies_ fetches a much larger price than mere iron. And owing to its
superiority it better accords with the loadstone, from which more powerful
quality it is often smelted, and it acquires the virtues from it more
quickly, retains them longer at their full, and in the best condition for
magnetical experiments. After iron has been smelted in the first furnaces,
it is afterward wrought by various arts in large worksteads or mills, the
metal acquiring consistency when hammered with ponderous blows, and
throwing off the dross. After the first smelting it is rather brittle and
by no means perfect. Wherefore with us (English) when the larger military
guns are cast, they purify the metal from dross more fully, so that they
may be stronger to withstand the force of the firing; and they do this by
making it pass again (in a fluid state) through a chink, by which process
it sheds its recremental matter. Smiths render iron sheets tougher with
certain liquids, and by blows of the hammer, and from them make shields and
breastplates that defy the blows of battle-axes. Iron becomes harder
through skill and proper tempering, but also by skill turns out in a softer
condition and as pliable as lead. It is made hard by the action of certain
waters into which while glowing it is plunged, as at Bambola and Tarazona
in Spain: It grows soft again, either by the effect of fire alone, when
without hammering and without water, it is left to cool by itself; or by
that of grease into which it is plunged; or {24} (that it may the better
serve for various trades) it is tempered variously by being skilfully
besmeared. Baptista Porta expounds this art in book 13 of his _Magia
Naturalis_. Thus this ferric and telluric nature is included and taken up
in various bodies of stones, ores, and earths; so too it differs in aspect,
in form, and in efficiency. Art smelts it by various processes, improves
it, and turns it, above all material substances, to the service of man in
trades and appliances without end. One kind of iron is adapted for
breastplates, another serves as a defence against shot, another protects
against swords and curved blades (commonly called scimitars), another is
used for making swords, another for horseshoes. From iron are made nails,
hinges, bolts, saws, keys, grids, doors, folding-doors, spades, rods,
pitchforks, hooks, barbs, tridents, pots, tripods, anvils, hammers, wedges,
chains, hand-cuffs, fetters, hoes, mattocks, sickles, baskets, shovels,
harrows, planes, rakes, ploughshares, forks, pans, dishes, ladles, spoons,
spits, knives, daggers, swords, axes, darts, javelins, lances, spears,
anchors, and much ship's gear. Besides these, balls, darts, pikes,
breastplates, helmets, cuirasses, horseshoes, greaves, wire, strings of
musical instruments, chairs, portcullises, bows, catapults, and (pests of
human kind) cannon, muskets, and cannon-balls, with endless instruments
unknown to the Latins: which things I have rehearsed in order that it may
be understood how great is the use of iron, which surpasses a hundred times
that of all the other metals; and is day by day being wrought by
metal-workers whose stithies are found in almost every village. For this is
the foremost of metals, subserving many and the greatest needs of man, and
abounds in the earth above all other metals, and is predominant. Wherefore
those Chemists are fools[76] who think that nature's will is to perfect all
metals into gold; she might as well be making ready to change all stones to
diamonds, since diamond surpasses all in splendour and hardness, because
gold excels in splendour, gravity, and density, being invincible against
all deterioration. Iron as dug up is therefore, like iron that has been
smelted, a metal, differing a little indeed from the primary homogenic
terrestrial body, owing to the metallick humour it has imbibed; yet not so
alien as that it will not, after the manner of refined matter, admit
largely of the magnetick forces, and may be associated with that prepotent
form belonging to the earth, and yield to it a due submission.
* * * * * {25}