chap. ii.

magnet stone, of what kind it is, and its discovery.

l oadstone, the stone which is commonly called the magnet, derives its name either from the discoverer (though he was not pliny's fabulous herdsman48, quoted from nicander, the nails of whose shoes and the tip of whose staff stuck fast in a magnetick field while he pastured his flocks), or from the region of magnesia in macedonia, rich in loadstones: or else from the city magnesia in ionia in afia minor, near the river mæander. hence lucretius says,

the magnet's name the observing grecians drew

from the magnetick region where it grew.

it is called heraclean from the city heraclea, or from the invincible hercules, on account of the great strength and domination and power which there is in iron of subduing all things: it is also called siderite, as being of iron; being not unknown to the most ancient writers, to the greeks, hippocrates, and others, as also (i believe) to jewish and egyptian writers; for in the oldest mines of iron, the most famous in asia, the loadstone was often dug out with its uterine brother, iron. and if the tales be true which are told of the people of the chinas, they were not unacquainted in primitive times with magnetical experiments, for even amongst them the finest magnets of all are still found. the egyptians, as manetho relates, gave it the name os ori: calling the power which governs the turning of the sun orus, as the greeks call it apollo. but later by euripides, as narrated by plato, it was designated under the name of magnet. by plato in the io, nicander of colophon, theophrastus, dioscorides, pliny, solinus, ptolemy, galen, and other investigators of nature it was recognized and commended; such, however, is the variety of magnets and their points of unlikeness in hardness, softness, heaviness, lightness, density, firmness, and friability of substance: so great and manifold are the differences in colour and other qualities, that they have not handed down any adequate account of it, which therefore was laid aside or left imperfect by reason of the unfavourable character of the time; for in those times varieties of specimens and foreign products never before seen were not brought from such distant regions by traders and mariners as they have been lately, and now that all over the globe all kinds of merchandise, stones, woods, spices, herbs, metals, and ore in abundance are greedily sought after: neither was metallurgy so generally cultivated in a former age. there is a difference in vigour; as whether it is male or female: for it was thus that the ancients used often to distinguish many individuals of the same species. pliny quotes from sotacus five kinds; those from æthiopia, macedonia, bœotia, the troad, and asia, which were especially known to the ancients: but we have posited as many kinds of loadstones as there are in the whole of nature regions of different kinds of soil. for in all climates, in every province, on every soil, the loadstone is either found, or else lies unknown on account of its rather deep site and inaccesible position; or by reason of its weaker and less obvious strength it is not recognized by us while we see and handle it. to the ancients the differences were those of colour49, how they are red and black in magnesia and macedonia, in bœotia red rather than black, in the troad black, without strength: while in magnesia in asia they are white, not attracting iron, and resemble pumice-stone. a strong loadstone of the kind celebrated so often nowadays in experiments presents the appearance of unpolished iron, and is mostly found in iron mines: it is even wont to be discovered in an unbroken lode by itself: loadstones of this sort are brought from east india, china, and bengal, of the colour of iron, or of a dark blood or liver colour; and these are the finest, and are sometimes of great size, as though broken off a great rock, and of considerable weight; sometimes single stones, as it were, and entire: some of these, though of only one pound weight, can lift on high four ounces of iron or a half-pound or even a whole pound. red ones are found in arabia, as broad as a tile, not equal in weight to those brought from china, but strong and good: they are a little darker in the island of elba in the tuscan sea, and together with these also grow white ones, like some in spain in the mines of caravaca: but these are of lesser power. black ones also are found, of lower strength, such as those of the iron mines in norway and in sea-coast places near the strait of denmark. amongst the blue-black or dusky blue also some are strong and highly commended. other loadstones are of a leaden colour, fissile and not-fissile, capable of being split like slates in layers. i have also some like gray marble of an ashen colour, and some speckled like gray marble, and these take the finest polish. in germany there are some perforated like honeycombs, lighter than any others, and yet strong. those are metallick which smelt into the best iron; others are not easily smelted, but are burned up. there are loadstones that are very heavy, as also others very light; some are very powerful in catching up pieces of iron, while others are weaker and of less capacity, others so feeble and barren that they with difficulty attract ever so tiny a piece of iron and cannot repel an opposite magnetick. others are firm and tough, and do not readily yield to the artificer. others are friable. again, there are some dense and hard as emery, or loose-textured and soft as pumice; porous or solid; entire and uniform, or varied and corroded; now like iron for hardness, yea, sometimes harder than iron to cut or to file; others are as soft as clay. not all magnets can be properly called stones; some rather represent rocks; while others exist rather as metallick lodes; others as clods and lumps of earth. thus varied and unlike each other, they are all endowed, some more, some less, with the peculiar virtue. for they vary according to the nature of the soil, the different admixture of clods and humours, having respect to the nature of the region and to their subsidence in this last-formed crust of the earth, resulting from the confluence of many causes, and the perpetual alternations of growth and decline, and the mutations of bodies. nor is this stone of such potency rare; and there is no region wherein it is not to be found in some sort. but if men were to search for it more diligently and at greater outlay, or were able, where difficulties are present, to mine it, it would come to hand everywhere, as we shall hereafter prove. in many countries have been found and opened mines of efficacious loadstones unknown to the ancient writers, as for instance in germany, where none of them has ever asserted that loadstones were mined. yet since the time when, within the memory of our fathers, metallurgy began to flourish there, loadstones strong and efficacious in power have been dug out in numerous places; as in the black forest beyond helceburg; in mount misena not far from schwartzenberg50; a fairly strong kind between schneeberg and annaberg in joachimsthal, as was noticed by cordus: also near the village of pela in franconia. in bohemia it occurs in iron mines in the lessa district and other places, as georgious agricola and several other men learned in metallurgy witness. in like manner in other countries in our time it is brought to light; for as the stone remarkable for its virtues is now famous throughout the whole world, so also everywhere every land produces it, and it is, so to speak, indigenous in all lands. in east india, in china, in bengal near the river indus it is common, and in certain maritime rocks: in persia, arabia, and the islands of the red sea; in many places in æthiopia, as was formerly zimiri, of which pliny makes mention. in asia minor around alexandria and the troad; in macedonia, bœotia, in italy, the island of elba, barbary; in spain still in many mines as aforetime. in england quite lately a huge power of it was discovered in a mine belonging to adrian gilbert, gentleman51; also in devonshire and the forest of dean; in ireland, too, norway, denmark, sweden, lapland, livonia, prussia, poland, hungary. for although the terrestrial globe, owing to the varied humours and natures of the soil arising from the continual succession of growth and decay, is in the lapse of time efflorescing through all its ambit deeper into its surface, and is girt about with a varied and perishable covering, as it were with a veil; yet out of her womb ariseth in many places an offspring nigher to the more perfect body and makes its way to the light of day. but the weak and less vigorous loadstones, enfeebled by the flow of humours, are visible in every region, in every strath. it is easy to discover a vast quantity of them everywhere without penetrating mountains or great depths, or encountering the difficulties and hardships of miners; as we shall prove in the sequel. and these we shall take pains so to prepare by an easy operation that their languid and dormant virtue shall be made manifest. it is called by the greeks52 ἑράκλιος, as by theophrastus, and μαγνῆτις; and μάγνης, as by euripides, as quoted by plato in the io: by orpheus53 too μαγνῆοσα, and σιδερίτης as though of iron: by the latins magnes, herculeus; by the french aimant54, corruptly from adamant; by the spaniards piedramant: by the italians calamita55; by the english loadstone and adamant stone56, by the germans magness57 and siegelstein: among english, french, and spaniards it has its common name from adamant; perhaps because they were at one time misled by the name sideritis being common to both: the magnet is called σιδερίτης from its virtue of attracting iron: the adamant is called σιδερίτης from the brilliancy of polished iron. aristotle designates it merely by the name of the stone:58 Ἔοικε δὲ καὶ θαλῆς ἐξ ὧν ἀπομνημονεύουσι, κινητικόν τι τὴν ψυχὴν ὑπολαβεῖν, ἔιπερ τὸν λίθον ἔφη ψυχὴν ἔχειν, ὅτι τὸν σίδηρον κινεῖ: de anima, lib. i. the name of magnet is also applied to another stone differing from siderite, having the appearance of silver; it is like amianth in its nature; and since it consists of laminæ (like specular stone)59, it differs in form: in german katzensilber and talke.