, 1875-08-14
TOughenea GLASS;

precilcally unbreakable would be 10 confer s
benefit upun humanity. Until now all effort,
| in this direction have failed. Patience and
perseverance will, however, do much, and
discovery has been lately announced which
will reyoluti0nize the manufacture and in
crease 10 fabulous extent the uses Of glass
This discovery has been made by French
gentleman. AsFrancois De Ia Bastie. a. d Is
the result of years of experiment and labor.
By the kindness OF Messrs, Rev, of Mincing
Lane. the agents Of II. De la Bastie, We
have been enabled to inspect this invention,
and to be present at the application of tests
which are absolutely decisive as to irs success.
The brittleness of glass is caused by the
want Of cohesion of its particles This
absence of cohesion is So great that q sndden
change OF temperature is sometimes suficier t
20 make 1t fly 10 pieces, and delicate glass is
shiveryd by the slightest shock II has long
been known that a gradual process Of cooling
adds to the cohesion Of the particles Of glass:
and plate glas, and indeed all kinds of sup
rior glass, cooled very gradually in what
are termed annealing ovens The idea oc-
CURED to NJ De la Bastie that by some modi-
fcation OF the process far better result migh
be obtained, and after many experiments he
found that sudden plunge into bath Of oil
when the glass wsS still at cherry heat ap.
peared entirely 10 change it's properties. At
first he could only succeed in occasional in
stances in rendering the glass unbreakable,
but by slow degree and endless experiments
as the exact degree Of hat required he sue
eeeded III establishing an unf,lling rule
Thus he found that were the glass cuuled in
the slightest degree in lis passage from the
oven to the oil bath, the required effects were
not obtained. In practice, therefore, he tips
the glass directly from its stand in the oven
into the bath placed beside IL.
The process in no way alters the appearance
of the glass, nor detracts from i,s clearneSs OF
Transparency To the eye the glass remains
as before, but its proP-rties-indeed, 1t may
be said, its very nature Is changed. We saw
watch glass and sheets of window glass
thrown high into air and fall nPcn he ground
with a crash some III falling came hall
across a wooden chair in way which wouId
- ---rr-A tho s'--.s.saa' and thickest ordi-
nary glass had it fallen from one fifth of the
height; We saw delicate glass plates thrown
reeklessly on to the hOor, and window glas>
glass might, no doubt, have been broken
with hammer, but it would defy all Ordi-
nary risks of breakage. Not only were thr
properties Of the glass changed, but its very
nature was, as has been said, altered. 1t had
acquired so great hardness that it conld no
longer be cut with diamond. 1t had lorr
much Of its power of conducting hea'i and
" hen broken by deliberate force 1t split uP
into n thousand fragments, which were So
destitute Of the ordinary sharpness Of glass
mat oLt NDuiu lihll-s bhC A''AAA AAi'c . "'N
full Of them and bring out handful wItkOu
fear of cutting the fingers. Hence 1t wa
evident that the hole molecular arrange
ments Uf The particles composing II had bes
modified. This loss of conducting power and
this change in fracture testified alike TO the
fact that the alteration WAS not a mere sur
face change, but was extended through the
whole b dy If the glase; and this was further
conclusiveiy proved by the fact that sOmr
plate glass. treated in the rough state, and
afrerward ground down to little more Than
half i's original thickness, could not be cut
with the diamond. No change OF ,empera
ture Subsequent TO the alteration affects the
glass, or deprives 1t Of I's strength We saw
all argand chimney which had been over and
over again heated almost TO redness at one
end, while the temperature at the other re-
manned unaltered, and yet 1t was as unbreak-
able as at first We saw water boiled IN a
rough and very thick glass DO on the fire,
and then taken off aud left to cool, and The
! experiment had been repeated dozens Of time-
without impairing its properties. The sue
cess Of ih- Invention Is indeed complete and
| unoestionabie Although it cannot be cut
! with the diamond, the glass can be engraved
with the sand blast, aud can be ground IN
the same manner as other glass The t"ei
Of its resisting the Diamond Is u drawback
! as it would have 10 be cut into the sIzs re
| auired for windows before being treated III
| The oil bath, bat experiments are at pre7e Mt
! beng made which seem to pr mise favor
able result in cutting it by some other method;
| Hitherto the invention has not been worked
upon q large scale, the whole OF the glass nj
presen; operated upon having been treated by
NJ. De la Basic, who Is fortunately Pp--e~s-c
IF ample private means, III his sborato'y
| Works are az present IN course Of erection IL
France 10 work the invention commercially