_Extinct_, at an end, dead.

What are the names of the principal islands of Coral formation?

The New Hebrides, the Friendly Isles, the Navigator's Isles, the
Society Islands, the Marquesas, the Gambier group, and others. These
groups are separated from each other by channels or seas, wider than
those which divide the individual islands which form the respective
groups; but all these waters abound with shoals and minor islets,
which point out the existence of a common base, and show that the work
by which they will afterwards be united above the level of the sea is
continually going forward.

_Shoals_, shallows; places where the water is of little
depth.

_Minor_, less, smaller than others.

_Existence_, being.

What is a singular characteristic of the Coral Islands?

On all of them a plentiful supply of sweet and fresh water may be
obtained by digging three or four feet into the coral; and even within
one yard of high-water mark such a supply is to be found. They are
mostly covered with a deep rich soil, and well wooded with trees and
evergreens of different kinds. These islands vary in extent, as well
as in the degree of finish to which they have arrived; some of the
largest being about 30 miles in diameter, and the smallest something
less than a mile;--all of various shapes, and all formed of living
coral.

_Diameter_, a straight line through the middle of a circle.

Is Coral put to any use by man?

White Coral, which is nowhere so abundant as about the shores of
Ceylon, and others of the neighboring Indian coasts, is employed as
lime by the inhabitants of that part of the world, for building
houses, &c., by burning it after the manner of our lime. This coral
lies in vast banks, which are uncovered at low water. Coral,
particularly the beautiful red sort, is likewise made into various
ornaments, as necklaces, &c.

Of what is our Lime composed?

Of a useful earth, which absorbs moisture and carbonic acid, and
exists as limestone, or in marble and chalk, which, when burnt, become
lime: in its native state it is called carbonate of lime, and is burnt
to disengage the carbonic acid; when made into a paste, with one part
water and three parts lime,[13] and mixed with some other mineral or
metallic substances, it forms plastic cements and mortars; and
afterwards, imbibing carbonic acid from the atmosphere, it becomes
again carbonate of lime, as hard as at first; and hence it