*
Wrought iron has in itself certain parts Boreal and Austral:
A magnetick vigour, verticity, and determinate
_vertices, or poles_.
Iron settles itself toward the North and South; not with one and the same
point toward this pole or that: for one end of the piece of ore itself and
one extremity also of a wrought-iron wire have a sure and constant
destination to the North, the other to the South, whether the iron hang in
the air, or float on water, be the iron large rods or thinner wires. Even
if it be a little rod, or a wire ten or twenty or more ells in length; one
end as a rule is Boreal, the other Austral. If you cut off part of that
wire, and if the end of that divided part were Boreal, the other end (which
was joined to it) will be Austral. Thus if you divide it into several
parts, before making an experiment on the surface of water, you can
recognize the vertex[86]. In all of them a Boreal end draws an Austral and
repels a Boreal, and contrariwise, according to the laws magnetical. Yet
herein wrought iron differs from the loadstone and from its own ore,
inasmuch as in an iron ball of any size, such as those used for artillery
or cannon, or bullets used for carbines or fowling-pieces, verticity is
harder to acquire and is less apparent than in a piece of loadstone, or of
ore itself, or than in a round loadstone. But in long and extended pieces
of iron a power is at once discerned; the causes of which fact, and the
methods by which it acquires its verticity and its poles without use of a
loadstone, as well as the reasons for all the other obscure features of
verticity, we shall set forth in describing the motion of direction.
* * * * *
{32} CHAP. XIIII.
Concerning other powers of loadstone, and its
_medicinal properties_.
Dioscorides prescribes loadstone to be given with sweetened water, three
scruples' weight, to expel gross humours. Galen writes that a like quantity
of bloodstone avails. Others relate that loadstone perturbs the mind and
makes folk melancholick, and mostly kills. Gartias ab Horto[87] thinks it
not deleterious or injurious to health. The natives of East India tell us,
he says, that loadstone taken in small doses preserves youth. On which
account the aged king, Zeilam, is said to have ordered the pans in which
his victuals were cooked to be made of loadstone. The person (says he) to
whom this order was given told me so himself. There are many varieties of
loadstone produced by differences in the mingling of earths, metals, and
juices; hence they are altogether unlike in their virtues and effects, due
to propinquities of places and of agnate bodies, and arising from the pits
themselves as it were from the matrices being soul. One loadstone is
therefore able to purge the stomach, and another to check purging, to cause
by its fumes a serious shock to the mind, to produce a gnawing at the
vitals, or to bring on a grave relapse; in case of which ills they exhibit
gold and emerald, using an abominable imposture for lucre. Pure loadstone
may, indeed, be not only harmless, but even able to correct an over-fluid
and putrescent state of the bowels and bring them back to a better
temperament; of this sort usually are the oriental magnets from China, and
the denser ones from Bengal, which are neither misliking nor unpleasant to
the actual senses. Plutarch and Claudius Ptolemy[88], and all the copyists
since their time, think that a loadstone smeared with garlick does not
allure iron. Hence some suspect that garlick is of avail against any
deleterious power of the magnet: thus in philosophy many false and idle
conjectures arise from fables and falsehoods. Some physicians[89] have that
a loadstone has power to extract the iron of an arrow from the human body.
But it is when whole that the loadstone draws, not when pulverized and
formless, buried in plasters; for it does not attract by reason of its
material, but is rather adapted for the healing of open wounds, by reason
of exsiccation, closing up and drying the sore, an effect by which the
arrow-heads would rather be retained in the wounds. Thus vainly and
preposterously do the sciolists {33} look for remedies while ignorant of
the true causes of things. The application of a loadstone for all sorts of
headaches no more cures them (as some make out) than would an iron helmet
or a steel cap. To give it in a draught to dropsical persons is an error of
the ancients, or an impudent tale of the copyists, though one kind of ore
may be found which, like many more minerals, purges the stomach; but this
is due to some defect of that ore and not to any magnetick property.
Nicolaus puts a large quantity of loadstone into his divine plaster[90],
just as the Augsburgers do into a black plaster[91] for fresh wounds and
stabs; the virtue of which dries them up without smart, so that it proves
an efficacious medicament. In like manner also Paracelsus to the same end
mingles it in his plaster for stab wounds[92].
* * * * *