Various - Harper's New Monthly Magazine, No. IX.—February, 1851.—Vol. II.

Among the strangest phenomena observed in glass are those which are peculiar to tubes. A glass tube placed in a horizontal position before a fire, with its extremities supported, will acquire a rotatory motion round its axis, moving at the same time toward the fire, notwithstanding that the supports on which it rests may form an inclined plane the contrary way. If it be placed on a glass plane – such as a piece of window-glass – it will move from the fire, although the plane may incline in the opposite direction. If it be placed standing nearly upright, leaning to the right hand, it will move from east to west; if leaning to the left hand, it will move from west to east; and if it be placed perfectly upright, it will not move at all. The causes of these phenomena are unknown, although there has been no lack of hypotheses in explanation of them. 8 8 The most plausible reason assigned is that of the expansion of the tube toward the fire by the influence of the heat. The fallacy of this theory is at once shown by the fact that, although heat does expand bodies, it does not increase their weight; therefore, notwithstanding that one side of the tube may be expanded, its equilibrium will remain unimpaired.

It is not surprising that marvels and paradoxes should be related of glass, considering the almost incredible properties it really possesses. Seeing that it emits musical sounds when water is placed in it, and it is gently rubbed on the edges; that these sounds can be regulated according to the quantity of water, and that the water itself leaps, frisks, and dances, as if it were inspired by the music; seeing its extraordinary power of condensing vapor, which may be tested by simply breathing upon it; and knowing that, slight and frail as it is, it expands less under the influence of heat than metallic substances, while its expansions are always equable and proportioned to the heat, a quality not found in any other substance, we can not be much astonished at any wonders which are superstitiously or ignorantly attributed to it, or expected to be elicited from it. One of the most remarkable is the feat ascribed to Archimedes, who is said to have set fire to the Roman fleet at the siege of Syracuse by the help of burning-glasses. The fact is attested by most respectable authorities, 9 9 Diodorus Siculus, Tzetzez, Galen, Lucian, Anthemius, and others. but it is only right to add, that it is treated as a pure fable by Kepler and Descartes, than whom no men were more competent to judge of the possibility of such an achievement. Tzetzez relates the matter very circumstantially; he says that Archimedes set fire to Marcellus's navy by means of a burning glass composed of small square mirrors, moving every way upon hinges; which, when placed in the sun's rays, directed them upon the Roman fleet, so as to reduce it to ashes at the distance of a bow-shot. Kircher made an experiment founded upon this minute description, by which he satisfied himself of the practicability of at least obtaining an extraordinary condensed power of this kind. Having collected the sun's rays into a focus, by a number of plain mirrors, he went on increasing the number of mirrors until at last he produced an intense degree of solar heat; but it does not appear whether he was able to employ it effectively as a destructive agent at a long reach. Buffon gave a more satisfactory demonstration to the world of the capability of these little mirrors to do mischief on a small scale. By the aid of his famous burning-glass, which consisted of one hundred and sixty-eight little plain mirrors, he produced so great a heat as to set wood on fire at a distance of two hundred and nine feet, and to melt lead at a distance of one hundred and twenty, and silver at fifty; but there is a wide disparity between the longest of these distances and the length of a bowshot, so that the Archimedean feat still remains a matter of speculation.

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 10 This story is attested, with slight variations, by several writers, Petronius, Dion Cassius, Pliny, and Isidorus. Pliny says that the populace, imagining that their interests would be injured by the discovery, destroyed the workhouse, tools, and dwelling of the artificer. 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 11 Blancourt. 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.