MAGNETISM. 
any time with their several north poles in 
contact, the whole will be thereby weak- 
ened ; whereas, by leaving a piece of com- 
mon iron attached to a magnet, the latter 
will acquire strength. It is also well known 
that some pieces of steel quickly receive 
the magnetic influence, while others require 
considerable labour, and after all are 
scarcely impregnated. The oxide of iron 
cannot be impregnated, and those bars 
that have been so, when they become, par- 
tially oxydized, lose their power. Hence 
we see the necessity of preserving the nee- 
dles of compasses from rust. 
Magnets have the power to act notwith- 
standing the intervention of substances in 
any degree porous between them, and the 
body to be acted upon : thus, if a needle 
be put on a sheet of paper, and a magnet 
be drawn under it, the needle will follow 
the course of the magnet. The peculiar 
affinity of the load-stone for iron is em- 
ployed, with great success, by those who 
work in precious metals, for the separation 
of filings, &c. of iron from the smaller parti- 
cles of gold, &c. A magnet being dipped 
into the vessel, in Which the whole are 
blended, will attract all ferruginous parti- 
cles. 
To communicate the magnetic power to 
a needle, let it be placed horizontally, and 
with a magnet in each hand, let the north 
pold of one, and the south pole of the other 
be brought, obliquely, in coptact over tlie 
centre of the needle ; draw them asunder, 
taking care to press firmly, and preserving 
the same angle or inclination to the very 
ends of the needles, which should be sup- 
ported by two magnets, whose ends ought 
to correspond in polarity with those of the' 
needle. Observe to carry the magnets you 
press with clear away from the ends of the 
needle, at least a foot therefrom ; repeat 
the friction in the same manner several 
times, perhaps six, eight, or ten times, and 
the needle will be permanently magnetized. 
As we have already stated, by using other 
magnets in succession, the powers of the 
needle will be proportionably increased. 
But no effect will result from the friction 
if the bars are rusty, or, indeed, not highly 
polished j their angles must be perfect, and 
their several sides and ends completely 
flat. 
It is, perhaps, one of the most curious of 
the phenomena attendant upon this occult 
property, that the centre of every magnet 
is devoid of attraction ; yet, that when a 
needle is placed in a line vvitli a magnet. 
and within the influence of its pole, that 
needle also becomes magnetic ; or, rather, 
a conductor, possessing a certain portion of 
attractive power : and it is no less extraor- 
dinary, that the magnet retains its power- 
even in the exhausted receiver of an air- 
pump : this seems to be a formidable ob- 
jection to its being influenced by any fluid., 
Perhaps the opinion entertained by many 
of our most popular lecturers on this sub- 
ject, viz. that the earth itself is the great 
attractor^ may be nearest the truth. We 
are the more supposed to incline towards 
such an hypothesis, knowing that, at the 
true magnetic equator, the needle does 
not dip ; and from the well ascertained 
fact, that bars of iron, placed for a length 
of time exactly perpendicular, receive a 
strong magnetic power, their lower ends 
repelling the south, but attracting the north 
poles of magnets applied to them re- 
spectively. Th,e direction of the dipping 
needle was ascertained by one Robert Nor- 
man, about 250 years ago. He suspended 
a small magnetic needle, by means of a fine 
thread around its centre, so as to balance 
perfectly, over a large magnet : the south 
pole of the former was instantly attracted 
by-the north pole of the latter. He found 
that so long as the needle was held exactly 
centrical, at about two inches above tlie 
magnet, it remained horizontal ; but so soon 
as withdrawn a little more tow'ards one end 
than the other of the magnet, the equili- 
brium was destroyed, and that pole of the 
needle which was nearest to either pole of 
the magnet was instantly attracted, and 
pointed downwards thereto. By the mag- 
netic equator, we mean a circle passing 
round the earth at right angles with tlie 
magnetic poles, which do not correspond 
with the geographical poles, as may be 
fully understood by-the indications of all 
compasses to points diflfering from the lat- 
ter; and as the indications of compasses 
vary so much both at different times and 
places, we may reasonably conclude, that 
the magnetic poles are not fixed. The varia- 
tion of the dipping needle has not, in our 
latitude at least, varied more than half a 
degree since its depressive tendency was 
first discovered by Norman. 
The suspension of Maliomefs body, in 
the temple where it was deposited, is sup- 
posed to have resulted entirely from mag- 
netism, with wliich the Arabians were com- 
pletely unacquainted. 
'Magnetism, animal. About 30 years 
ago, Father Hehl of Vienna, imposed on 
O S 
