The Yale expositor., 1910-08-26


III are inherently symbolical of beau
ty, strength and permanence. They
preserve the tradition of something
stable and enduring. Mans use of
marble and granite has, of course,
dated from the days of antiquity; in
deed, of all components of the earth's
crust, no two, perhaps, have been
more universally pressed into the serv-
ice of construction and decoration.
The worlds yield of the finer classes
of marble proceeds from many coun-
tries, Italy. France. Belgium, Norway,
Sweden and America being especially
prolific in deposits.
Apart from the British Isles, where.
in particular, the gray Aberdeen and
red Peterhead varieties are justly
famed, granite occurs in Sweden, the
Tyrol, Italy. Sardinia, North America
and other districts.
Qualities of Marble and Granite.
In chemical composition marble is
essentially calcium-carbonate, or car
onate of lime. AS q consequence, the
stone is very sensitive to the action
of chemical agents present in the at
mosphere. On the other hand, while
marble is in this way more rapidly at
tackled than many other stones, its
power to resist the mechanical agents
of weathering, which are generally the
lively durable substance. The great
variety of colors shown by marble is
due mainly to the presence of compan-
ion minerals. Iron, when present in
the ferrous state, produces color vary
ing from light to dark green manga
nese and cobalt involve pinkish hues.
Accessory minerals, In short, give rise
10 an almost endless association and
blending of colors, shades, veins and
patterns.
Granite is a crystalline-granular ag-
gregate of quartz, felspar and mica,
and comprises all varieties of texture.
Generally 1t is the constituent felspar
which gives the rudy or the gray APP
pearance differentiating the rock. I'm
like marble, granite cannot be split up
with saws, and hence the expense and
labor of quarrying and preparing the
latter material for building and other
purposes 10 IeldllNGly 6lCalSis
According to the state geologist of
Georgia, probably no building stone in
the United States has in recent years
met with such universal favor and
given greater satisfaction than Geor-
gia marble. l. is, however, curious
10 learn that, Notwithstanding the
enormous quantity of native marble
capable of being quarried, and the
large number of undeveloped deposits
which the United States as a whole
possesses, considerable supplies of the
material are imported (mostly from
italy, for statuary purposes and In
terror decoration. The growth of the
use of Georgia marble for public
buildings in America is, however, pro-
ceeding on satisfactory lines, and its
merits are becoming generally known.
The imposing Minnesota state capitol
was built of white marble from the
Amicalola quarries, Pickens county
the Rhode Island state capitol. the Car.
negie public library, Atlanta, and the
Corcoran art gallery, Washington, OF
stone from the quarrfes of a southern
marble company
Greek Marbles.
In recent years the extensive quar-.
ri OF Mount Pentelicus, range stu
ated eight miles northeast of Athens,
have been re-explored. and are being
worked by a British company. From
this classical center came the material
used in the erection of some of the
worlds most famous buildings, among
them the Parthenon and the Propy.
laea. Pentelikon marble is almost pure
carbonate of lime. Owing, however, to
the presence of minute grains of by.
rites, the marble, which is a clear
white on being worked. assumes a
soft ivory tint after exposure, a fea.
ture which materially adds to its value
TO- decorative purposes. Blocks oil
immense size, up TO 1000 tons, in fact
are frequently dislodged from the
quarry bed. and, with suitable ma
ohinery, may be cut to any required
dimensions. The private railway oi