225 
UNBREAKABLE OR TOUGHENED GLASS : A NOVEL 
MODE OF MANUFACTURE. 
By PERRY F. NURSEY, C.E. 
[PLATE CXXIL] 
A CONSIDERABLE degree of well-merited attention lias 
of late been directed towards an invention which may be 
justly termed remarkable, even in these days of startling dis- 
coveries, inasmuch as it is one which promises to effect a com- 
plete change in the physical character of glass. This invention 
is the toughening process of M. Franpois Royer de la Bastie, 
by which the natural brittleness of ordinary glass is exchanged 
for a condition of extreme toughness and durability. And this 
invention is perhaps the more remarkable in that it does not 
emanate from one engaged in, or practically conversant with, the 
manufacture of glass, nor is the discovery due to one of the 
great lights of science of our day ; neither was it the result of 
a happy momentary inspiration. On the contrary, M. de la 
Bastie is a French private gentleman of fortune, residing in his 
native country, who, however, is given to the study of scientific 
matters. He was educated as an engineer, but his position and 
means rendered it unnecessary for him to follow the profession 
into which he had been initiated. He, however, is fond of 
experimenting in matters relating to engineering, and amongst 
other things he, some years since, conceived the idea of render- 
ing glass less susceptible to fracture, either from blows or from 
rapid alternations of heat and cold. The early training of his 
mind naturally led him to look to mechanical means for the 
accomplishment of this end ; and he, in the first place, set 
himself a purely mechanical problem to solve. He thought — 
as did Sir Joseph Whitworth with regard to steel — that by 
submitting glass when in a soft or fluid condition to great 
compressive power, he should force its molecules closer together, 
and, by thus rendering the mass more compact, the strength 
and solidity of the material would be greatly increased. This 
was not an unreasonable line of argument, inasmuch as the 
VOL. XIV. — NO. LVI. Q 
