Evening star., 1909-07-10
WHY STONE BUILDINGS DECAY

the cutting and dressing, 1t was thought
to be in prime condition. Quarryman and
builder were intensely surprised il stone
handled in this way went to pieces and
disintegrated in few years after having
been set in a building. Until more sar-
Gus study of economic geology was made
it was not recognized that heavy blast
ing. even severe blows from slcdges.
had A tendency to weaken the cementing
material that holds together the rock
grains or crystals I'm any stone. Now
quarryman would think of placing on the
market stone that had been stunned.
Even In continental Europe, which is AL
ways backward in discarding old meth
DDS and adopting modern Improvements.
this lesson has been learned. 1t was for
merly the practice to blast out stone. even
in marble qnarrieS. The effect upon the
delicate materials. especially such mar
bles as were brecciated or with elaborate
tapestried patterns caused, of course. by
the mingling of different elements) can
readily be ina gined. This is the reason
why the old marble quarries of Europe
present such remarkable spaIl banks. the
debris often preventing necessary devel-
opment work. Slowly but surely the
wasteful powder man IS being displaced.
and in his stead is installed the wire saw.
which cuts the stone from its native bed
without injurinS its texture il the slight
est. Here I'm America we use the chan
neling machine. which cuts the stone into
rectangular blocks with the minimum Of
waste and does not stun the stone"
Still another great improvement. the
writer tells us. has come in a knowledge
of the necessity for "a proper sea asoning OF
stone While the presence of interstital
water. sap" in all stone has been
recognized for d century. the part that it
plays In weatherins was unknown until
recently:
THE quarryman and stoneworker found
that a stone fresh from its bed and full
of quarry water was easy TO work, and
that II grew harder when the sap had
dried out. Hence stone was frequently
cut and set in building before ii had
seasoned and thus fell victim to frost.
Now the architect and the builder know
the danger in certain varieties of green
stone and provide against il in their spec
ificatiOns No one expecting a satisfac-
tory and durable job would think of usi:g
unseasoned timber and similar safe
guards are called for in the use Of stone
Much of the defective stonework OF
the past was caused by neglect OF a fun
damental principle In stone masonry-tte
need to set all stone Of markedly strait
fled or laminated formation on its natural
bed. As such stone splits most readily
along the plane of stratification. the cas-
lest way was TO split il up for thin ashar
and set it upright in the wall. But this
quality of cleavage naturally caused 1t
to scale off as moisture and frost got a
lodgment. While a disregard of this pre-
caution is responsible for a large portion
of the defective stonework of the past
fifty years. it has played no part in recent
work and the future is secure.
THE advocates of stone need ask tor
their material only the same measure OF
intelligent precaution that is taken in the
use of any other material. There have
been thousands of instances of disa ster
often costly In human life following the
use of poorly mixed concrete. badly burn
ed and improperly laid brick. and defec-
tive iron and steel work. The percentage
of failure In stone Is lower than In any
other material If choice is made of stone
that has proven its suitability to climatic
conditions; If il has been quaried i'm a
scientific manner: if Ii has been thor
oughly seasoned, and if ii is properly laid.
We may be sure that we have empioyed
the most durable material of construction
that is available"