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BOOK V
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85
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it.
His death and that of Ptolemy who ordered that the statue should be of
his sister intervened. Dinocrates has been copied by the Arabs for in
this same manner they have made the iron bier, in which Mohammed is
said to be preserved, hang in the air in his temple in Mecca, according
to certain people. Pliny also relates that this power of lodestone to
attract iron was revealed to its discoverer when the iron nails of his
sandals and the ferrule of his staff adhered to a lodestone when he was
tending his flock. In a similar fashion it was demonstrated to our own
miners who worked in the iron mine called Magnes, mentioned above, when
they quit work. After a hard day's work the miners were accustomed to
throw their hammers and wedges on the floor of the mine working and on
the following day when they would return to work the tools were not
found in the places where they had been left but on the backs of the
workings where they would be suspended, having been drawn there by the
strength of this mineral. The miners, ignorant of this natural
phenomenon, believed it to be an indication of the approval of the
Gods. After they found out that it was a vein of lodestone they would
amuse themselves by hanging their tools from the ore. This same power
reveals the mineral to sailors. The Moors relate that abundant
lodestone is found on certain rugged shores of India and that it will
draw the nails from a vessel that approaches these places and will even
draw vessels loaded with iron to the shore and stop the journey. Pliny
relates that the Ethiopian mineral is so strong that it will draw all
other lodestone to itself. Lodestone will not attract iron that is
covered with rust, impure iron or iron that has been smeared with the
juice of onion or garlic.
To
no less degree, diamond resists its power. If a diamond is placed next
to iron a lodestone cannot draw it or if iron has been attracted to the
stone as soon as a diamond is placed along side of it the iron will
drop. When lodestone is removed from iron ore for a long time it loses
part of its strength and to prevent this it must be covered with iron
filings. There have been periods when glass workers have used this
mineral because they believed that it, in itself, influenced the
fluidity of the glass just as it influenced iron, according to Pliny.
Even doctors have used it. Dioscorides relates that when one-half dram
is drunk in water sweetened with honey it will draw out a dense humor.
Galen states that it has properties similar to hematite. Since it has
the same color as hematite after it is burnt, the latter is sometimes
sold for lodestone. Dioscorides preferred that which attracted iron
with ease, had a color inclined to blue, was dense and not very heavy.
Theamedes has
the opposite power to lodestone since the latter attracts iron, the
former repels it. It occurs in a mountain of Ethiopia not far from the
mountain where lodestone is found. If the memory of Pliny was not at
fault and the source from which he copied it correct, there are two
similar mountains in India near the Indus river. The nature of the one
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