The new North-west. [volume] (Deer Lodge, Mont.) 1869-1897, 1875-05-28
Toughsned Glass.
From the London Times.

About seven years since, M. Francois de
Ia Bastie, French engineer, after long
and patient investigation into the subject,
discovered simple means of rendering
glass practically unbrittle, and at the same
| time preserving its transparency. Broadly
stated, it consists in heating the glass at a
certain temperature and plunglng it while
| hot into bath consisting of a heated olea-
ginous compound. There are, however,
many conditions in connection with the de-
| tails OF the process upon which satisfac-
tory result depends, and the neglect of any
even in slight degree, constitutes the
difference between success and failure.
Thus, the glass may be underheated and
will not be susceptible to the effect of the
bath, or it may be overheated and then it
will lose its shape, or, again, it may be
rightly heated and yet be spoiled i'm the
course of ftransference to the bath. More
over, the oleaginous constituents OF the
bath and their temperature have an i'm
portant bearing upon the ultimate result.
These and numerous other 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
process can be carried out practically with
out fear of mischance. The time occupied
in the actual process of tempering is merely
nominal, for ordirectly the articles are brought
to the required temperature they are plung-
sx<o %1c hot s,,cA vxSfh axvs,
The cost, of tempering to, is stated to be
| very small.
The physical properties of the material
become altered in very remarkable man
ner. To this singular fact we can testify,
from the inspection of a number of tough
| ened glass articles at the offices of Messrs.
Abel Rey and brothers, 30 Mincing Lane,
| the representatives Of M. de la Bastie in
England. In these articles, which consist
ed of watch glasses, plates, dishes and sheet
glass, both colored and plain, neither trans
parency nor color is affected at all. and the
ring or sound only slightly. These arti-
cles. some of them being exceedingly thin
were thrown indiscriminately across II
room against wall and fell spinning OH
the deal floor. Water was boiled in sau-
| Ger over fire and the saucer was quickly
removed to a comparatively cold place, and
| was unaffected by the sudden change of
temperature. One corner of q piece Of
glass was held by the hand in a 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 COM
| parative experiment was then made with a
piece of ordinary plate glass and similar
piece Of toughened glass, in order to sh ow
| their respective powers of resistance to
fracture from the force OF impact by a fal-
ling weight. In each case the glass was
about six inches square, and was placed in
frame, the weight being dropped upon its
center. With the ordinary glass 2 ounce
brass weight, falling on it from height of
IL inches and IS inches respectively, did no
damage, but at "a inches the glass was bro
| ken into seye raj fragments. With thin
ner piece of toughened glass, no impression
was made by the same weight falling from
heights ranging from 2 to 10 feet, the
weight simply rebounding from the glass.
An ounce iron weight, tried ate feet and
feet respectively, gave similar results.
Upon the height being increased to 6 feet,
however, the glass broke. But here an
other singular result was produced; instead
Of breaking into about dozen pieces, as
did the ordinary glass, it was literally
smashed to atoms. The largest fragments
measured half an inch in length and
breadth, and these were easily reduced by
the fingers to atoms varying in size from
that of a pins point to that of pins head.
The lines of fracture in the fragments pre-
sented to the eye appearance of irregular
| lace work, and the lines were, moreover,
apparent to the touch, but more palpably
SO on one side of the glass than ON the 9th
er. Which of the two sides was the one
that received, the first impact of the blow
we were not able to determine. Another
popularity is that the edges of the fracture
are by no means 80 sharp, and therefore
capable of causing incised 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 disintegration extends
throughout the whole piece, the atoms nc
longer possessing the power of cohesion.
OF the practical nature of M. de la Bastie'l
unique discovery, there can be no question
J whatever, nor can there be any doubt of it:
value i'm the arts, sciences, and manufac.
lures. The applications which suggest
themselves are innumerable; and above a,l(
beyond the usefulness Of the process with
regard to articles of domestic use, come i'm
portant considerations affecting the applied
, sciences, especially in connection will
; / chemical manufactures and similar indus
| tries, where q material, alike nninfuencet
by the action of heat or acids, has been 81
, long and SO vainly sought for-notably II
connection with vitriol chambers in th'
manufacture Of snlphuric acid, and fo
] piping in chemical works. For the presen
, there remains one purpose to which tough
= 4
ened glass cannot be so easily applied, ant
D that is to window glazing in odd sizes, a
il cannot be cut by diamond or other or
/ binary means. Our GLACIERS will therefor
have respite, but we cannot give then
4 much hope that it will prove long one, a
experiments of considerable promise are be
ing conducted with the view of solving thi
I problem. Moreover, the glass can be Gu
TO the proper sizes before tonghening If dc
sirable. The glass, however, is readily on
: graved, either by fluoric acid in the usua
2 way, on by Mr.. Tilghman's elegant san'
D blast process. It can be easily polished
4 and il can also be cut by the wheel. as 10
! luster work and the like.
A THE TEXAS CATTLE DRIvE..-The dro
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