The Helena independent. [volume] (Helena, Mont.) 1875-1943, 1890-08-13
ROMAN BUILDING MATERIALS.


They We're Mostly Concrete OF SMALL
Lumps Of Stone.
From the arch@ologist's point Of view the
subject 10 an important one, az in many
cases the strength, prosperitv, or even the
very existence Of an ancient city has de-
pended on the local supply Of stone or brick
with which defenses against rival towns or
foreign enemies could be constructed, says
the Saturday Review. Rome itself is .
good example of this; every one of it's
many hills consists of q soft volcanic
tufa, which could easily be worked into
blocks for wallis of defense even by
the bronze tools of the prehistoric { settlers
on the Palatine and Capitoline hills. Later
on, when iron tools had come into common
use, the harder volcanic peperino from the
Alban hills wss readily obtained, and
formed circuit walls Of great strength and
durability. Next in order Of time came the
use of the beautiful travertine limestone
from the cliffs of Thur, and lastly, under
the empire, when magnifcence and
not military strength was aimed at
in the capital Of the worlds con-
querors, there was no longer any re-
the most gorgeous marbles, GRANTEES and al
abasters of every hue were poured into
Rome in almost incOnceivable abundance.
Whole armies of slaves were necessarily
laboring in the marble quarries of Africa,
Arabia. Asia Minor and Greece, and inn
ployed in Transporting the great blocks or
columns to the long Marmoratum or Mar
BILE Quay, which occupied nearly half mile
of. the Tiber bank below the Aventine
hill. In the main. however, the
local material which did the most to make
home the Eternal City was, not her rich
stores of stone or brick clay, but rather
that wonderful natural cement, the pozzo-
lana, which in some far-distant period was
showered down out of volcanic craters in
the Alban Hills, and formed bed of con-
siderable thickness over nearly the whole
surface of the Campagna Of Rome. This
curious volcanic product, which looks like
a red and rather earthly sort of gravel, has
the property. when mixed with lime. of
forming hydraulic cement of the great
est strength and durability.
Throughout the whole period Of the en-
pire the chief building material of Rome
was concrete made of small Jumps Of stone
or broken brick bedded in matrix of the
pozzOlana cement. This mixture, as soon
as 1t had set, became much harder than
most building stones, and each wall or
vault formed one coherent mass, as if it had
been cut out of a solid macs of rock. The
extraordinary strength of this kind of
DulAu1uk udb Docu COubCtiuIly tosGeO uUIAuB
the last ten years or 80 of destruction of
old buildings-the unhappy result of the
rapid growth of the modern capital of
Italy. The massive blocks of the grand old
"Wall of the Kings" near the railway sta
tion and in the gardens of Sallust were re-
moved and utilized for the new succeed
barracks with comparative ease. But the
massive concrete walls we're far too
much for the pick and hammer of the
demolishers; dynamite alone was of
sufficient force to shatter the obdurate
masses. The pozzolana is found in great
beds in various parts of Italy. It's earliest
use seems to have been at Puteoli, near
Naples, whence came it's Latin name of
Lapis puteolanus. And even in districts
where none of this volcanic earth was to be
found the ancient Romans imported it in
pretension.