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POPULAR SCIENCE REVIEW. 
fragility of glass results from the weakness of the cohesion of 
its molecules. Success, however, did not follow experiment, 
and the mechanical problem was laid aside unsolved. 
M. de la Bastie, however, continued to regard the question 
from an engineering point of view, and turned his attention to 
another method of treatment. Aware that the tenacity of steel 
was increased, and that a considerable degree of toughness was 
imparted to it by dipping it, while hot, into heated oil, he 
experimented with glass in a similar manner. The results were 
sufficiently successful to encourage him to persevere in this 
direction, and, by degrees, to add other fatty constituents to 
the oil bath. Improved results were the consequence ; and they 
continued to improve until at length, after several years of 
patient research and experiment, De la Bastie succeeded — with a 
bath consisting of a mixture of oils, wax, tallow, resin, and 
other similar ingredients— -in producing a number of samples of 
glass which were practically unbreakable. As may be supposed, 
there were other conditions upon which success depended 
besides the character and proportions of the ingredients con- 
stituting the bath. M. de la Bastie, not being a glass manu- 
facturer, purchased sheets of glass, as well as glass articles, 
which he heated in a furnace or oven, to a certain temperature, 
and transferred to the oleaginous bath, which was also heated 
to a given temperature. These questions of relative tempera- 
ture, therefore, had to be worked out ; and De la Bastie had 
further to determine, very precisely, the condition of the glass 
most favourable for the proper action of the bath upon it. 
This he found to be that point at which softness or malleability 
commences, the molecules being then capable of closing sud- 
denly together, thus condensing the material when plunged into 
a liquid at a somewhat lower temperature than itself, and 
enclosing some portion of the constituents of the bath in its 
opened and susceptible pores. Having determined all these 
conditions, and constructed apparatus, M. de la Bastie was 
enabled to take ordinary glass articles, and pieces of sheet 
glass, and to toughen them so that they bore an incredible 
amount of throwing about and hammering without breaking. 
Just, however, as De la Bastie had perfected his invention, he 
lost the clue to success, and for two years he was foiled in every 
attempt to regain it. There was the hard fact staring him in 
the face, that he had succeeded in depriving glass of its brittle- 
ness, as shown by specimens around him ; but there was the 
harder fact before him, that he had lost the key of his success. 
Nevertheless he laboured on, and at the end of the period above 
mentioned he had the satisfaction of finding all his anxieties at 
an end ; his toils were requited by the re-discovery of his secret. 
He has since worked at it most assiduously, and has now 
