The New Orleans bulletin. [volume] (New Orleans [La.]) 1874-1876, 1875-05-04
TOUGHENED GLASS,
A WONDERFUL DISCOVERY.

About seven years since, NJ. Francois de
la Bastie, French engineer after long and
patient investigation into the subject, dis
covered simple means Of rendering glass
practically unbrittle, and at the same time OF
preserving its transparency. Broadly stated,
it consists in heating the glass at certain
bath consisting Of heated oleaginous COM
pound. There are, however, many condi-
tons in connection with the details Of the
process upon which satisfactory result de-
ponds, and the neglect of any, even in a
slight degree, constitutes the difference be-
tween success and failure. Thus, the glass
may be underheated and will not be suscept-
ible to the effect of the bath, or it may bs
overheated and it will then lose its shape,
or. again, it may be rightly heated and yet be
spoiled in the course of transference to the
bath Moreover the oleaginous constituents
of the bath and their temperature have an i'm
portant bearing upon the ultimate result.
These and other numerous points of detail
have all been satisfactorily settled by NJ. de
La Bastie, who has designed furnaces and
baths by means of which his toughening pro-
cess can be carried out practically without
fear of mischance. The time occupied in the
actual process of tempering is merely noml-
nal, for directly the articles are brought to
the required temperature they are plunged
into the bath and instantly Withdrawn. The
cost of tempering, too, is stated to be very
small.
The physical properties of the material be-
come altered in very remarkable manner.
To this singular fact we can testify, from the
inspection of q number of toughened glass
articles at the Office of Messrs. Abel Rsy and
Brothers, 80 Mincing lane, the representa-
a 1lo Ia in Enn0ond 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 articles, some of them being
exceedingly thin-were thrown indiscrlmi.
nately across o room against a wall and fell
spinning on the deal floor. Water was boiled
in saucer over a fire and the saucer was quick
ly removed to comparatively cold place, and
was unaffected by the sudden change OF
temperature. One corner of piece OF glass
was held by the hand in gas flame until
the corner became exceedingly hot, but the
heat was not communicated to the other
portion of the glass, neither was it cracked
from UNEQUAL expansion. A comparative ex-
pertinent was then made with piece Of or
binary plate glass and a similar piece OF
toughened glass, in order to show their
respective powers of resistance to frac-
ture from the force of impact by q
falling weight In each case the glass
was about six inches square, and
was placed in frame, the weight being
dropped on its center. With the ordinary
glass, 2-ounce brass weight, falling on it
from o height Of IL inches and 18 inches re-
spectively, did no damage; but at "a inches
the glass was broken into several fragments.
With a thinner piece of toughened glass, no
impression was made by the same weight
falling from heights ranging from feet to 10
feet, the weight simply rebounding from off
the glass. An S-ounce iron weight, tried at
2 feet and 4 feet respectively, gave similar re-
suits. Upon the height being increased to 6
feet, however, the glass broke.
OF the practical nature of NJ. de 10 Bastie' 5
unique discovery there can be no question
whatever, nor can there be any doubt of its
value in the arts, sciences and manufactures.
The applications which suggest themselves
are innumerable, and above and beyond the
usefulness of the process with regard to ar
ticles of domestic use, come important con-
siderations affecting the applied sciences, es-
pecially in connection with chemical manu-
features and similar industries, where ma
terial, alike uninAuenced by the action Of
heat or acids, has been so long and SO vainly
sought for--notaoly in connection with vitr;ol
chambers in the manufacture Of sulphuric
acid, and for piping in chemical works. The
glass is readily engraved, either by fuoric
acid in the usual way, or by Mr.. Tilghman S
elegant sand blast process. 1t can be easily
polished, and it can also be cut by the wheel,
as for luste- work and the ike.-Londoa
Times.