WHY IS NOT GLASS MALLEABLE?
In the region of glass, we have a puzzle as confounding as the philosopher's stone (which, oddly enough, is the name given to that color in glass which is known as Venetian brown sprinkled with gold spangles), the elixir vitæ, or the squaring of the circle, and which has occasioned quite as much waste of hopeless ingenuity. Aristotle, one of the wisest of men, is said, we know not on what authority, to have originated this vitreous perplexity by asking the question. "Why is not glass malleable?" The answer to the question would seem to be easy enough, since the quality of malleability is so opposed to the quality of vitrification, that, in the present state of our knowledge (to say nothing about the state of knowledge in the time of Aristotle) their co-existence would appear to be impossible. But, looking at the progress of science in these latter days, it would be presumptuous to assume that any thing is impossible. Until, however, some new law of nature, or some hitherto unknown quality shall have been discovered, by which antagonist forces can be exhibited in combination, the solution of this problem may be regarded as at least in the last degree improbable.
Yet, in spite of its apparent irreconcilability with all known laws, individuals have been known to devote themselves assiduously to its attainment, and on more than one occasion to declare that they had actually succeeded, although the world has never been made the wiser by the disclosure of the secret. A man who is possessed with one idea, and who works at it incessantly, generally ends by believing against the evidence of facts. It is in the nature of a strong faith to endure discouragement and defeat with an air of martyrdom, as if every fresh failure was a sort of suffering for truth's sake. And the faith in the malleability of glass has had its martyrology as well as faith in graver things. So far back as the time of Tiberius, a certain artificer, who is represented to have been an architect by profession, believing that he had succeeded in making vessels of glass as strong and ductile as gold or silver, presented himself with his discovery before the Emperor, naturally expecting to be rewarded for his skill. He carried a handsome vase with him, which was so much admired by Tiberius that, in a fit of enthusiasm, he dashed it upon the ground with great force to prove its solidity, and finding, upon taking it up again, that it had been indented by the blow, he immediately repaired it with a hammer. The Emperor, much struck with so curious an exhibition, inquired whether any body else was acquainted with the discovery, and being assured that the man had strictly preserved his secret, the tyrant instantly ordered him to be beheaded, from an apprehension that if this new production should go forth to the world it would lower the value of the precious metals.[10] The secret, consequently, perished. A chance, however, arose for its recovery during the reign of Louis XIII., a period that might be considered more favorable to such undertakings; but unfortunately with no better result. The inventor on this occasion submitted a bust formed of malleable glass to Cardinal Richelieu, who, instead of rewarding him for his ingenuity, sentenced him to perpetual imprisonment, on the plea that the invention interfered with the vested interests of the French glass manufacturers.[11] We should have more reliance on these anecdotes of the martyrs of glass, if they had bequeathed to mankind some clew to the secret that is supposed to have gone to the grave with them. To die for a truth, and at the same time to conceal it, is not the usual course of heroic enthusiasts.
Many attempts have been made to produce a material resembling glass that should possess the quality of malleability, and respectable evidence is not wanting of authorities who believed in its possibility, and who are said to have gone very near to its accomplishment. An Arabian writer[12] tells us that malleable glass was known to the Egyptians; but we must come closer to our own times for more explicit and satisfactory testimony. Descartes thought it was possible to impart malleability to glass, and Boyle is reported to have held the same opinion. But these are only speculative notions, of no further value than to justify the prosecution of experiments. Borrichius, a Danish physician of the seventeenth century, details an experiment by which he obtained a malleable salt, which led him to conclude that as glass is for the most part only a mixture of salt and sand, he saw no reason why it should not be rendered pliant. The defect of his logic is obvious; but, setting that aside, the fallacy is practically demonstrated by his inability to get beyond the salt. Borrichius also thought that the Roman who made the vase for Tiberius, may have successfully used antimony as his principal ingredient. Such suppositions, however, are idle in an experimental science which furnishes you at once with the means of putting their truth or falsehood to the test. There is a substance known to modern chemistry, luna cornea, a solution of silver, which resembles horn or glass, is transparent, easily put into fusion, and is capable of bearing the hammer. Kunkel thought it was possible to produce a composition with a glassy exterior that should possess the ductile quality; but neither of these help us toward an answer to Aristotle's question. Upon a review of the whole problem, and of every thing that has been said and done in the way of experiment and conjecture, we are afraid we must leave it where we found it. The malleability of glass is still a secret.