The daily dispatch. [volume] (Richmond [Va.]) 1850-1884, 1875-05-04
from the London Times

! to overcome its inherent brittleness and lin.
bility to fracture. and at the same time To
preserve its trans parepcy. have proved sue.
cessful-if. indeed, they have ever been
made. which is doubtful II is true that the
French philosopher Reaumur many years
since hardened glass somewhat by exposing
it to high temperature for con.
siderable time. But this process, which
is technically termed identification, while
it hardens, at the same time crystallizes
the glass and renders it opsque, the produc;
being known as Rcaumer's porcelain. Seven
years since. however, NJ. Francois de la Bas-
tie. n French engineer, after long and patient
investigation into The subject, discovered Il
simple means of rendering glass practically
unbrittle, aud at the same time Of preServ-
ing its transparency. There were many
delicate conditions involved in the process
by which be obtained this result, his success
being achieved much in the same way as Pal
liSSy'S, but on cndeavoring to repeat the sue.
cessful experiment he failed signaIly. For
two years more N. dc Ia Bastic, who pos
scsscS ample means, strove without avail
10 rediscover the secret OF his sue
cess. AT length, however, he succeed
ell in SO doing, and has since been
engaged in perfecting his invention
into practical working. The process of con-
version in the main is very simple one so
simple that 1t seems singular it was never
thought Of before. Broadly stated, 1t con.
siSts in heating the glass to certain temper
ature and plungirig it while hot into bath
consisting Of heated oleaginous compound.
There are, however, many conditions IN con-
nection with the details Of the process upon
which satisfactory result depends. and the
neglect of any, even in a slight degree, con-
Sti,utes the difference between success and
failure. Thus the glass may be underheat-
ed, and may not be susceptible to the effect
of the BATH, or il may be over
heated. and then 1t will lose its
shape; or, again, it may be rightly heated,
and yet be spoiled in the course OF
transfercncc to the bath. Moreover, the
olcaginous constituents Of the bath and their
temperature have an important bearing upon
the ultimate result. These and numerous
other points Of detail have all been satStac-
torily settled by NJ. de Ia Bastie, who has de-
signed furnaces and baths by means Of which
his toughening process can be carried out
practically without fear of mischance. The
time occupied in the actual process Of tenn
pernc is merely nominal, for directly the
articles are brought 10 the required tempera-
lure IutN axe pibbSSls lhlO thC Dulh ahu III
s,antly withdrawn. The cost Of tempering,
too, is stated to be very small.
We have observed that NJ. de Ia Bastie
went through 4 long course OF experimental
research before he attained success. be first
worked, as an engineer naturally would,
uron mechanical principles. Knowing that
the fragillty OF glass results from the weak
ness Of the cohesion Of its molecules he not
unreasonably expected that by forcing these
molecules more closely together, and thus
rendering the mass more compact, the
strength and solidily Of the material would
be increased. But this doctrine, which holds
good with iron and steel, Is Sir Joseph
Whitworth has practically demonstrated,
does not apply to glass. compression failing
! to tougher it even il applied 10 it when in
/ fluid or soft condition. By applying heat,
however, which is only force in another form,
| the desired end is attained. and the physical
| properties OF the material become altered in
s. very remarkable manner. To this singular
! fact we can testify, from the inspection OF
number of tuughened-gias articles at the Of
fees of Messrs. Abel Rey & Brothers, 20
Mncing lane, the representatives OF NJ. de Ia
BaS'e in England. In these articles, which
consisted Of watch glasses, plates. dishes, and
sheet glass, both colored and plain, neither
Transparency nor color is affected at all, and
the ring or sound only slightly. These arti-
cles, some Of them being exceedingly thin,
were thrown inoiscriminately across room
against a wall and tell spinning on the deal
floor. Water was boiled in saucer oyera
fire, and the saucer was quickly removed TO
comparatively cold place, and was unaffected
10y the sudden change of temperature One
corner OF piece Of glass was held By the
tha hnpn mo
exceedingly hot, but the heat was not
communicated to the other portion Of the
CLASS, neither was it cracked from unequal
expansion. A comparative experiment was
then made with i piece Of ordinary plate
glass aud Il similar piece OF toughened glass,
in order 10 show their respective powers Of
resistance 10 fracture from the force of i'm
pact by a falling weight. In each case the
glass was about six inches square, and was
placed in frame. the weight being dropped
upDn its centre. With the ordinary glass,
a tWO-ouuce brass weight falling On il from
q height of II and Is inches respectively
did no damage, but al "a inches the glass
was broken into several fragments. With
a thinner piece of tUughuneu glass no I'M
preston was made by the same weight
falling from heights ranging from to
10 feet. the weight simply rebound
ing from off the glass. An eight.
ounce iron weight. tried at and feet
rcspcc,iyclv. gave similar results. Upon the
height being increased to SIX feet, however,
me class broke. But here another singular
result WAS produced; instead of breaking
into about dozen pieces, Is did the ordl-
nary glass, it was literally smashed to atoms.
The ltrvest fragments measured about nall
All inch iu- leugtb and breadth, and these
we're easily reduced by the fingers to atoms
VARYING in size from that Of pins point TO
1hx of a large pins bead. The llscs OF trac-
tnre- In the fragments presented TO the eye
Tie .ppearsnce Of irregular lace work, and
these liues were, moreover, apparent 10 the
touch, but more palpaby on one side OF the
glass than the other. Which of the t%o sides
was The one that received the first impact OF
the blow we are not able to determine. An
other REGULARITY il that the edges OF the
fracture is by no means so sharp, ana there
fore capable Of causing inclsed wounds, as
are those of ordinary glass. 1t would seem
that the toughened glass possesses enormous
cohesive power, but that If the equilibrium
Of the mass is disturbed at any one point the
disturbance or disntegration Instantly eX-
tends throughout the whole piece, the atoms
no longer possessing the power OF coheslon.
OF the practical nature OF NJ. de la Baslle'S
uniuue discovery there can be no question
whutever, nor can there be any douot OF It's
value in the arts, sciences, and manufactures.
The anplications which suggest themselves
are inuumerable, and above and beyond the
usefulness of the process with regard TO arti-
cles of domestic use come important consld-
erations affecting the applied sciences, espe-
riallv in connection with chemical manufac-