Reverting
to the subject of Rubies—the Tourmaline was first brought to Europe
from Ceylon by the Dutch, " who gave it," says Harry Emanuel (1867), "
the name of c Aschentrekker,' from its sometimes
attracting, and sometimes repelling, hot ashes when these were laid
near it for any length of time." This Tourmaline will not only attract
ashes from burning coals, but will also repel them again, in an amusing
way : for, as soon as a small quantity of warm ashes leap upon it, and
appear as if they were endeavouring to writhe themselves by force into
the stone, they, in a little time, spring from it again, as if about to
make a new attempt. Its possessed quality of acquiring magnetic powers,
and becoming electrically " polar" by means of heat, readily
distinguishes the Tourmaline from any other gem. Otherwise this is
considered by some to be a Chrysolite when yellow, and a Sapphire when
blue ; being sold under such, and other spurious names. The crystals of
Tourmaline are occasionally parti-coloured ; frequently, those found in
Elba are red at one end, yellow in the middle, and black, or brown, at
the other end. These stones, when heated, or rubbed, acquire a
different degree of electricity at each end respectively. And, if
broken whilst thus electrically affected, their fragÂments, like
artificial magnets, present opposite poles. The lapidary, when cutting
Tourmaline for optical uses, has to remember that it is only
transparent in one direction, parallel with the axis of the crystal;
otherwise it will appear opaque on looking through it. The powers of
polarising light which the Tourmaline exhibits make it of particular
optical use. These powers are so special that when the Stone is cut into
