THE HISTORY AND MYSTERY OF THE GLASS-HOUSE
Upward of two thousand years ago, perhaps three, a company of merchants, who had a cargo of nitre on board their ship, were driven by the winds on the shores of Galilee, close to a small stream that runs from the foot of Mount Carmel. Being here weather-bound till the storm abated, they made preparations for cooking their food on the strand; and not finding stones to rest their vessels upon, they used some lumps of nitre for that purpose, placing their kettles and stew-pans on the top, and lighting a strong fire underneath. As the heat increased, the nitre slowly melted away, and flowing down the beach, became mixed up with the sand, forming, when the incorporated mass cooled down, a singularly beautiful, transparent substance, which excited the astonishment and wonder of the beholders.
Such is the legend of the origin of Glass.
A great many centuries afterward – that is to say, toward the close of the fifteenth century of the Christian era – when some of the secrets of the glass-house, supposed to have been known to the ancients, were lost, and the simple art of blowing glass was but scantily cultivated – an artificer, whose name has unfortunately escaped immortality, while employed over his crucible accidentally spilt some of the material he was melting. Being in a fluid state it ran over the ground till it found its way under one of the large flag-stones with which the place was paved, and the poor man was obliged to take up the stone to recover his glass. By this time it had grown cold, and to his infinite surprise he saw that, from the flatness and equality of the surface beneath the stone, it had taken the form of a slab – a form which could not be produced by any process of blowing then in use.
Such was the accident that led to the discovery of the art of casting Plate-Glass.
These are the only accidents recorded in the History of Glass. For the rest – the discovery of its endless capabilities and applications – we are indebted to accumulated observation and persevering experiment, which, prosecuting their ingenious art-labors up to the present hour, promise still farther to enlarge the domain of the Beautiful and the Useful.
The importance of glass, and the infinite variety of objects to which it is applicable, can not be exaggerated. Indeed it would be extremely difficult to enumerate its properties, or to estimate adequately its value. This thin, transparent substance, so light and fragile, is one of the most essential ministers of science and philosophy, and enters so minutely into the concerns of life, that it has become indispensable to the daily routine of our business, our wants, and our pleasures. It admits the sun and excludes the wind, answering the double purpose of transmitting light and preserving warmth; it carries the eyes of the astronomer to the remotest region of space; through the lenses of the microscope it develops new worlds of vitality which, without its help, must have been but imperfectly known; it renews the sight of the old, and assists the curiosity of the young; it empowers the mariner to descry distant ships, and to trace far-off shores, the watchman on the cliff to detect the operations of hostile fleets and midnight contrabandists, and the lounger in the opera to make the tour of the circles from his stall; it preserves the light of the beacon from the rush of the tempest, and softens the flame of the lamps upon our tables; it supplies the revel with those charming vessels in whose bright depths we enjoy the color as well as the flavor of our wine; it protects the dial whose movements it reveals; it enables the student to penetrate the wonders of nature, and the beauty to survey the marvels of her person; it reflects, magnifies, and diminishes; as a medium of light and observation its uses are without limit; and as an article of mere embellishment, there is no form into which it may not be moulded, or no object of luxury to which it may not be adapted.
Yet this agent of universal utility, so valuable and ornamental in its applications, is composed of materials which possess in themselves literally no intrinsic value whatever. Sand and salt form the main elements of glass. The real cost is in the process of manufacture.
Out of these elements, slightly varied according to circumstances, are produced the whole miracles of the glass-house. To any one, not previously acquainted with the component ingredients, the surprise which this information must naturally excite will be much increased upon being apprised of a few of the peculiarities or properties of glass. Transparent in itself, the materials of which it is composed are opaque. Brittle to a proverb when cold, its tenuity and flexibility when hot are so remarkable that it may be spun into filaments as delicate as cobwebs, drawn out like elastic threads till it becomes finer than the finest hair, or whisked, pressed, bent, folded, twisted or moulded into any desired shape. It is impermeable to water, suffers no diminution of its weight or quality by being melted down, is capable of receiving and retaining the most lustrous colors, is susceptible of the most perfect polish, can be carved and sculptured like stone or metal, never loses a fraction of its substance by constant use, and, notwithstanding its origin, is so insensible to the action of acids that it is employed by chemists for purposes to which no other known substance can be applied.
The elasticity and fragility of glass are among its most extraordinary phenomena. Its elasticity exceeds that of almost all other bodies. If two glass balls are made to strike each other at a given force, the recoil, by virtue of their elasticity, will be nearly equal to the original impetus. Connected with its brittleness are some very singular facts. Take a hollow sphere, with a hole, and stop the hole with your finger, so as to prevent the external and internal air from communicating, and the sphere will fly to pieces by the mere heat of the hand. Vessels made of glass that has been suddenly cooled possess the curious property of being able to resist hard blows given to them from without, but will be instantly shivered by a small particle of flint dropped into their cavities. This property seems to depend upon the comparative thickness of the bottom. The thicker the bottom is, the more certainty of breakage by this experiment. Some of these vessels, it is stated, have resisted the strokes of a mallet, given with sufficient force to drive a nail into wood; and heavy bodies, such as musket-balls, pieces of iron, bits of wood, jasper, bone, &c., have been cast into them from a height of two or three feet without any effect; yet a fragment of flint, not larger than a pea, let fall from the fingers at a height of only three inches, has made them fly. Nor is it the least wonderful of these phenomena that the glass does not always break at the instant of collision, as might be supposed. A bit of flint, literally the size of a grain, has been dropped into several glasses successively, and none of them broke; but, being set apart and watched, it was found that