a marine production, the secretion of a particular polyp, agglomerated
according to certain laws, and disposed so as to resemble small trees
the sea it is covered with an almost cartilaginous net work of very
delicate texture, covered with tubercles, in the centre of each of
which is the polyp, of a milky-white colour, and provided with eight
tentacles round the mouth. ' This net-work is called the bark of the
polypi ; it is more delicate and soft than the centre, and is taken off
in order to show the trunk, which, when out of the water, acquires the
hardness of marble.
The substance of coral is composed of carbonate of lime, of organic elements in a great quantity, and of phosphate of lime.
all calcareous substances, it does not resist the file; it can also be
cut, carved, engraved, and polished in the same manner as shells.
Alkalies do not corrode it, and in diluted acids it