The record-union., 1898-03-24
NODDED MARBLE.
Satisfactory Results Secured From
Experiments.

Experiments by John NicOlSOn, Pro-
fessor of Mechanical Engineering a.
McGill University, and myself have
demonstrated that under certain condi-
tions marble may be nodded like clay
and at the same time retain its entire
tensile strength. Satisfactory results
from these experiments have been Sc
cured after labors extending over three
years in the laboratory of McGill Uni
versity. The knowledge we have
gained is of equal Importance to the
scientific experimenter and the build
ers Of the great structures of stone that
are seen in the cities of both Canada
and the United States
1t is apparent that if marble will yield
to continuous pressure of a certain
force, without the aid of any process,
to soften it or render it in any way
more tractable, then there is a limit to
the pressure to which the lower stone
sections, the foundation of large build
ings, should be subjected
Our experiments have aimed at as
pertaining whether it is possible by sub
jecting rocks artificially to great pres
sure, under conditions which obtain
deep down in the earth's crust, to mold
them and cause them to flow like plas-
tic bodies. The material upon which
We have experimental so far is the
pure white statuary marble from Car
rara, and the experiments have shown
that this rock, so hard and brittle, may,
under certain conditions, be nodded
like clay
Small columns of the marble about
one and half inches high and one inch
in diameter We're accurately ground
and polished Heavy wrought iron
tubes were then made, initiating the
plan adopted in the construction of
heavy guns, by rolling long strips Of
Swedish iron around a bar of soft iron
and welding the strips to the bar as
they were rolled around it, The core
of soft iron comprising the bar was
then drilled out, leaving a tube of
Swedish welded iron, so constructed
that the fibers of the iron run around
the tube and thus give it great
strength, and at the same time, when
the pressure becomes sufficiently high,
allows it to bulge very considerably be-
tore breaking. This tube was then
very accurately fitted on to the column
of marble. This was accomplished by
giving a very slight taper to both the
column and the interior of the tube, and
so arranging it that the marble would
pass only about half way into the tube
when cold.
The tube was then expanded by heat
ing so as to allow the marble to pass
completely into it, leaving about three
quarters of an inch of free tube at eth
er end. On allowing the tube to cave
a perfect contact between the iron and
marble was obtained, and it was no
longer possible to withdraw the latter.
Into each end of the tube containing
the column an accurately fitting sliding
steel plug was inserted. and by means
of these the marble was submitted to
pressure far above that which would
be sufficient to crush it if not SO in
closed.
The machine employed in obtaining
the pressure was especially built for
these Investigations, and is so ar
ranged that the pressure may be main
tanned for weeks or months if REQUIRED.
Pressure Of from $1,000 to $4,000
pounds per square inch has been en-
ployed. Under these circumstances the
conditions of pressure to which the
marble is subjected are those found
deep down in the earths crust. in what
is known to biologists as the zone Of
fow"-that is to say, the marble /.
submitted to pressure far above that
which would be sufficient to crush it
but it cannot break or move until
very much higher pressure is reached.
under which the iron tube slowly gives
way, and is bulged out by the mar
bic, which acts like a fluid body with
in it.
The tube slowly buIges out until
very marked enlargement of the por-
ton surrounding the marble has taken
place. The tube is then cut omen
longitudinally along two lines on opno-
site sides by means of a milling ma
chine.
The marble within the tube is still
so hard and firm that it holds the two
sides of the tube together so firmly
that it is impossible to tear them apart
without mechanical aids
The marble adhering to each side ne
the tube can then be removed in a
solld block by opening out the metal
and the f1attened out column NAV hn
obtained by placing the two halves To-
gether. In one case the marble was
Hattened down to one-half its original
hlght-New York Herald.