The daily gazette., 1875-06-07

More about ZOu0hened Glass.
The Great MalleabfIity Of the New
Material-Its Utility In the INDUS

1hOTe dOONC IOU0hene0 CfLUSS
The Great MaIleabtIitv Of The New
,Materia!-Its Utility In the INDUS
trial Arts.
The invention Of q process for tough.
enlng glass by M. De la Bastie continues
TO attract great deal of attention, and
we present the following additional arti.
Gle on the new invention, from the Lon.
don Standard
This discovery has been made by a
French gentleman, M. Francois de la
bastie, and is the result of years Of ex-
perlence and labor. The brittleness of
glass ls caused by the want of cohesion
OF Its particles. This absence of cohe-
sion is 80 great that sudden change of
temperature is sometimes sufficient to
MAKE 1t ny to pieces, and delicate glass
IS shlvered by the slightest shock. It
has long been known that q gradual pro-
cess OF cooling adds to the cohesion of
the particles of glass; and plate glass.
and indeed all kinds of superior glass
are cooled very gradually in what are
termed annealing ovens. The idea oc-
CURED to M. de la Bastie that, by some
result might be obtained. and after yerv
many experiments he found that q sud
den plunge into bath of oil when the
glass was still at a cherry heat appeared
entirely to change its properties.
AT nrst he could only succeed in occa-
sional instances in rendering the glass
unbreakable, but by slow degrees and
endless experiments as to the exact de-
gree OF heat required he succeeded in
estab blishing an unfailing rule. Thus he
found that were the glass cooled in the
slgntest degree IN its passage from the
| oven to the oil bath, the required effects
were not obtained. In practice. there
fore, he tips the glass directly from its
stand in the oven into the bath placed
beside it. The process in no way alters
| the appearance OF the glass, nor detracts
from It's clearness or transparency.
10 the eye the glass remains as before.
put Its properties-indeed it may be said
Its very nature is changed. We saw
watch glasses and sheets Of window
glass thrown high into the air and fail
upon the ground with crash; some in
falling came half across wooden chair
in a way which would have snapped the
strongest and thickest ordinary glass
had it fallen from one-f fifth of the height
we saw delicate glass plates thrown reck-
lessly on to the floor, and window glass
placed under foot and trodden upon.
The glass might, no doubt, have been
broken with hammer, but it would
defy all ordinary risks of breakage.
Not only We're the properties of the |
glas3 changed, but its very nature was,
rs has been said. altered. It had ac-
quired so great hardness that it could /
no longer be cut with q diamond. It |
had lost much of its power of Conduct
ing heat. and when broken by deliberate
force it split up into thousand frag-
ments, which were so destitute of the
ordinary sharpness of glass that one
could plunge their hand into box full
OF them and bring out handful with
out fear OF cutting the fingers. Hence
it was evident that the whole molecular
arrangements OF the particles composing |
it had been modified. The loss Of con-
ducting power and this change in frac-
ture testified alike to the fact that the
alteration was not O mere surface change.
but was extended through the whole
body. OF the glass; and this was further
conclusively proved by the fact that
some plate glass, treated in the rough
state, and afterwards ground down to
little more than half its original thick
ness, could not be cut with diamond.
No change OF temperature subsequent
to the alteration affects the glass, or de-
prives. it of its strength. We saw an
argand chimney which had been over
and over again heated almost to redness
at one end, and yet it was as unbreaka.
BILE as at first. We saw water boiled in
a rough and very thick glass bowl on the
lire, and then taken off and left to cool,
and the experiment had been repeated
dozens of times without impairing its
properties. The success of the inven-
tion is indeed complete and unquestion-
able. Although it cannot be cut with
the diamond, the glass can be engraved
with tho sand blast, and can be ground !
In the same manner as other glass.
'Ihn fact nf Ita raaiSfine tha |
is drawback, as it would have to be
cut into the sizes required for windows
before being treated in the oil bath, but
experiments are at present being made |
which seem to promise favorable result
In cutting it by some other method. F.
Hitherto the invention has not been
worked upon large scale, the whole of ,
the glass at present operated upon hav-
ing been treated by M. De la Bastie, who 4
is fortunately possessed Of ample pri-
vate means, in his laboratory. Works
are in course of erection in France to t
work the invention commercially. Z
The advantages of this new invention
and the new fields which it opens for
the employment of glass are immense.
OF the benefit to housekcepors by the
rendering of all the table glass, win
dows, and pier glasses unbreakable, we G
need say nothing. for this will be appa- q
rent to every reader. In the article of a
glass chimneys alone the consumption |
8 at present enormous. We should be q
afraid to mention the number of mil
ions Of chimneys for lamps which we !
nave heard are manufactured yearly in .
France alone. Short indeed is the life !,
If chimney at present, and the con- !,
tant breakage is one reason why lamps
ire not much more extensively used 9
han they are. Ia