ds North and South, just as iron
touched with a loadstone does in shadow-clocks, and in compasses, and in
the mariners' compass. You will be able, if curious enough, to balance all
at the same time by fine threads a number of small rods, or iron wires, or
long pins with which women knit stockings; you will see that all of them at
the same time are in accord, unless there be some error in this delicate
operation: for unless you prepare everything fitly and skilfully, the
labour will be void. Make trial of this thing in water also, which is done
both more certainly and more easily. Let an iron wire two or three digits
long, more or less, be passed through a round cork, so that it may just
float upon water; and as soon as you have committed it to the waves, it
turns upon its own centre, and one end tends to the North, the other to the
South; the causes {31} of which you will afterwards find in the laws of the
direction. This too you should understand, and hold firmly in memory, that
* as a strong loadstone, and iron touched with the same, do not invariably
point exactly to the true pole but to the point of the variation; so does a
weaker loadstone, and so does the iron, which directs itself by its own
forces only, not by those impressed by the stone; and so every ore of iron,
and all bodies naturally endowed with something of the iron nature, and
prepared, turn to the same point of the horizon, according to the place of
the variation in that particular region (if there be any variation
therein), and there abide and rest.

* * * * *

CHAP. XIII.

*

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