The morning news. [volume] (Savannah, Ga.) 1887-1900, 1898-01-26
THE MOULDING OF MARBLE.
SOME INTERESTING EXPERIMENTS
IN PHYSICS.

New Light Upon Accepted Theories
of Glacial ActiOn-IrOn Merely
Very stir Liquid-PhenOmena of
Ice-High Buildings Concerned.
From the Chicago Inter-Oc Ocean.
Some very remarkable experiments just
reported by Profs. Adams and Nicholson
of McGill University in Montreal tend to
show that a substance so hard and brit
lie as marble may under certain condi-
tons. be nodded like clay. They passed
a miniature column of pure Carrara mar
bic in a sheath of iron and submitted it TO
graduated but long-continued pressure,
with the result that the marble shorten
ed and thickened, bulging so as TO swell
the, iron sheath. The iron then being cut
away, the marble, no longer cylindrical,
but greatly altered in shape. remained
still solid and brittle as before. No in
crease of temperature or other agency
than the pressure was applied in produc-
ing This result.
This experiment. remarkable in itself,
has implications that make it of peculiar
interest to persons as widely separated as
the scientific geologist and the practical
house builder. For on the one hand it
tends to throw light on intricate problems
as to the formation of the earth's crust,
while on the other it suggests a danger
from the building of such sky-scrappers as
are springing up in our cities, that hith-
erto has been quite overlooked. If mar
BILE one of the hardest OF stones, yields
and becomes plastic under sufficient pres
sure, then clearly there must be limit
to the hight to which one building stone
can be heaped upon another in the cree
ton of walls without mourning the dan
ger of such yielding of the stones of the
bottom of the wall as win endanger the
integrity of the entire structure. Short of
the point at which the stone crumbles
there is apparently point at which it
may slowly change its shape under stress
of steady and long-continueI pressure.
Thus there is introduced a new element
which the architect in estimating the
strength of material has overlooked. and
which must be reckoned with, if our mod
ern sky-crapers are to be permanent and
safe structures.
For the geologist, the interest in the proof
OF the Elasticity of marble rests on the
light 1t throws on certain obscure forrna-
tons of the earth's crust Ii proves that
under the conditions of pressure existing
deep IN the crust, stones may be nodded
into new shapes without being melted. In
point of fact, The nodded marble of these
experiments, when examined under The
microscope, was said to present many re-
sembianoes to certain natural rock whose
peculiar cleavage had been difficult to ex-
plain. II oftentiunes seems as if a LAYER of
rock had been twisted from the position
in which it apparently had formed. Some
times It is manifest from chemical
changes in the rock that it has been partly
melted during che process, and then there
is no difficulty in explaining it, but where
this fas not occurred IL was difficult to be-
lleYe that the change of shape has actually
taken place. But these experiments leave
no doubt in the matter. However brittle
a rock may seem to be, it is really. So it
appears, a plastic substance capable. I'M
der proper conditions of flowing into new
shapes as surely, if not readily, as putty
or dough is nodded.
Another interesting question on which
new light is thrown by this experiment is
the perpleXing one of the motion of gla-
ciers. As everybody knows. glacier is
in effect, sreat river of solid ice. 1t is
equally well known that the ice stream
flows along its channel, slowly to be sure
but just as surely as stream of water
The early students of glaciers doubted
this, but numberless careful observations
eliminating with the famous ones of Prof
T%ndail. have demonstrated the point be-
yond all controversy. OF course the bed
of the ice stream is usually steep. and
hence at first it seems nothing remark
able that the ice should slide along it,. So
the famous explorer of the Alps, De
Saussure who was among the first to re-.
cognize the motion of glaciers explained
this motion as mere sliding of the ice
Very soon. however, other observers saw
that this simple explanation by no means
suffced, for the most casual observation
showed that the channel through which
the glacier moves--its banks or borders
is not usually of uniform width from be-
ginning 10 end but on the contrary Wild
ems and narrows much as does the chan
mel of a river. And like the river of wa
ter. this river of ice at all times complete
~ hlls its channel, spreading out into la
goons of ice where the channel widens and
narrowing into slender stream as the
walls contract Clearly, then the ice
stream changes ats shape just as the
stream of water does; yer how is this pos
sible, SINCE ice is a solid, and a very brit
tie solid al that?
Numherless explanations have been put