avy hammers,
till the mass splits down. Another method of detaching masses of rock,
is by driving wooden wedges into a deep artificial or natural crack,
or fissure; the wedges are then wet, and, in consequence of swelling,
burst the rock asunder.

_Quarried_, from _to quarry_, a term used for the getting of
stone from a quarry, or place where stones are dug from the
earth, or detached from a large mass of rock.

_Detach_, to separate.

For what is this Rock used?

On account of its great hardness, it is used for large public
structures, as bridges, churches, &c. The ancient temples and other
buildings in Egypt, Asia, and Italy, were built of different colored
granites, especially the beautiful Oriental red granite.

What is Slate?

The common name for a bluish fossil stone, very soft when dug out of
the quarry, and easily cut or split into thin plates,--a property
which renders it invaluable for a variety of purposes.

_Invaluable_, extremely valuable.

For what is it used?

Slate has superseded the use of lead for covering roofs, even of the
largest buildings; being lighter and more durable, it is preferable to
tile: it is also employed for slabs to form cisterns, shelves for
dairies, and other purposes, on account of its strength, coolness, and
the ease with which it can be cleaned; the latter quality renders it
also of great value in the business of education, as a cheap
substitute for paper. The ancients were unacquainted with the use of
slate.

What other kinds of stone are used in building?

Limestone, or the calcareous rocks of the geologist: of these there
are many varieties. Those which are easily cut and polished are termed
marbles, and are used in sculpture and in ornamental architecture. The
coarser marbles are used for the common purposes of building.

_Calcareous_, partaking of the nature of calx or lime,--a
term employed to describe chalk, marble, and all other
combinations of lime with carbonic acid.

_Geologist_, one who studies the science of Geology.

Of what do Calcareous Earths or Stones consist?

Calcareous earths, stones, or rocks consist of lime, or pure
calcareous earth, carbonic acid, and water.

What is Quick-Lime?

Limestone deprived of its carbonic acid and water by being subjected
to an intense heat in a kiln.

How are these Stones wrought?

To whatever purpose the stones are to be applied, the larger block