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combustible, and does not absorb oil or moisture, render it
extremely valuable in the manufacture of electrical maehinery.
 It is practically the only material now used for
commutator bars, for which it is eminently suitable on account
 of ifs insulating properties, great durakility, and
perfect cleavage, in consequence of which it can be procured
of any d-sired thinness.
It is used frequently to separate the iron discs that go to
make up the iron core of an armature ; the completed core
is again very generally insulated with this material to keep
the armature conductors electrically separated from the iron
core ; in fact, mica is generally used in the manufacture of
all dynamo electric machines, alternators, transformers, and
electrical apparatus generally, on account of its insulating
properties, combined with the other advantages mentioned
above. It is also used for lamp chimneys and masks for
workers in furnaces, &amp;c., on account of its non-conducting
properties for heat. There is no reason why the Ceylon
trade in mica should not be more expanded in the future ;
the chief inconvenience in its working lies in its occurrence
in small quantities in diverse localities instead of in large
masses in a few places.

iron Ores.
A considerable amount of excellent iron, as well as steel,
was manufactured by the Sinhalese in past times, but the
production of iron has for long almost or quite ceased. So
far as is known, the amount of available iron ore is small and
would not repay exploitation at the present time.

Manganese.
Ore of manganese in small quantitiesis widely disseminated
in Ceylon.

Gems.
These are for the most part obtained from the river
gravels, consisting of the débris of the crystalline rocks,
The gems occurring in Ceylon, with some of their synonyms
and varieties, are as follows : — ]
Varieties of corundum, ruby, sapphire, Oriental amethyst,
Oriental topaz, star stones ; fopaz, including pink and colourless
 varieties ; fourmaline of various colours; chrysoberyl, including
 cat’s-eye and alexandrite ; zircon (hyacinth, jargoon,
Matara diamond) of various colours; spinel, blue or red,
including Balas ruby ; moonstone ; garnet, red and brownishyellow,
 known as cinnamon stone; and beryl (aquamarine),
The more definite kinds of each of these are easily recogaizable,
 but the numerous gradations of tints make some of
these stones difficult to classify, so that dealers with limited