Hindiya it is kaddhak and harbaj which as if is derived from ahanruba —
since the two letters ya' and jim become often interchanged in many
languages.
Dioscorides says that the best kind is the colour of lapis lazuli and
when burnt, becomes converted into haematite (shadanaj). We have
neither seen such a magnet nor heard about it.
An unknown author has said that its best variety is black tinged with
a little of red colour, followed by the kind that is of the colour of iron.
It is said that a mine full of it and having an excellent kind is around
Zabtarah on the frontiers of Rome.
It is said that the boats lying within the Caspian Sea have date tree
planks rabetted to each other, while those in Mediterranean Sea have the
planks joined by means of nails. This is because the hills in the Caspian
Sea contain considerable quantities of magnet, posing a danger to ordinary boats. It is otherwise in the other seas.
This explanation, however, is incorrect in that the boats which have
date planks in place of nails also contain the anchor, instruments and
tools made of iron, and iron goods, especially the Indian swords.
There are gold mines near Zabulistan, which comprise stones and also
the wells that are known as Zarwan. These are alongside the town of
Khashbaji. It is surrounded by hills in which occur silver, copper, iron
and lead mines. There are magnetic rocks here. The rocks exposed to
the sun possess less attractive power than those that are submerged under
water. I despatched a man there to bring a powerful magnet piece. He
told me that at the skirt of the mountain of Sharkan, he drew out a piece
with a shovel which did not weigh less than 4 rath. It seems that there
was not such attractive power in that side of the mountain, for, if the
partition between the two were removed, the attraction would have increased, since this spade was quite heavy and the power to attract grows
with the weight.
In the Kitab al-Rahmah, Jabir bin Hayyan says:
We had a magnet which could lift a weight of 1 00 dirhatns of iron.
After passage of time, it was unable to lift a weight of 80 dirhatns,
even though its weight had not diminished. All that happened was
that its gravitational pull had been reduced.
This opinion is in accordance with our view that the magnet piece
which is in direct contact with the air and the sun loses its gravitational
force. Jabir further writes:
I had a 30 istar (= 19.5 grammes] piece which was able to draw 600
dirharns worth of weight of iron. Thirty istar weight is equivalent to
130 dirharns. 112 It was thus able to draw a weight equivalent to
three and one-third times.
This is indeed a strange and unique fact. Wartak the Magian displayed
