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VITRUM (ὕαλος), glass. A singular amount of ignorance and scepticism long prevailed with regard to the knowledge possessed by the ancients in the art of glass-making. Some asserted that it was to be regarded as exclusively a modern invention, while others, unable altogether to reply the mass of evidence to the contrary, contented themselves with believing that the substance was known only in its coarsest and rudest form. It is now clearly demonstrated to have been in common use at a very remote epoch. Various specimens still in existence prove that the manufacture had in some branches reached a point of perfection to which recent skill has not yet been able to attain; and although we may not feel disposed to go so far as Winckelmann (I. c2 §20), who contends that it was employed as an ordinary material for all manner of domestic utensils by the Egyptians, Greeks, and Romans.
We find the process of glass-blowing distinctly represented in the paintings of Beni Hassan, which if any faith can be reposed in the interpretation of hieroglyphics according to the phonetic system,a were executed during the reigns of Osirtasen the First, the contemporary of Joseph, and his immediate successors, while a glass bead has been found at Thebes bearing the name of a monarch who lived 3300 years ago, about the time of the Jewish Exodus. Vases also, wine-bottles, drinking-cups, bugles, and a multitude of other objects have been discovered in sepulchres and attached to mummies both in Upper and Lower Egypt, and although in most cases no precise date can be affixed to these relics, many of them are referred to by the most competent p1210 judges to a very early period. (Wilkinson, Ancient Egyptians, vol. III p88, &c.).
A story has been preserved by Pliny (H. N. XXXVI.65), that glass was first discovered accidentally by some merchants who having landed on the Syrian coast at the mouth of the river Belus, and being unable to find stones to support their cooking-pots, fetched for this purpose from their ship some of the lumps of nitre which composed the cargo. This being fused by the heat of the fire, united with the sand upon which it rested and formed a stream of vitrified matter. No conclusion can be drawn from this tale, even if true, in consequence of its vagueness; but it probably originated in the fact recorded by Strabo (XVI p758) and Josephus (B. J. II.9), that the sand of the district in question was esteemed peculiarly suitable for glass-making, and exported in great quantities to the workshops of Sidon and Alexandria, long the most famous in the ancient world (see Hamberger and Michaelis on the Glass of the Hebrews and Phoenicians, Commentar. Soc. Gott. vol. IV; Heeren, Ideen, I.2 p94). Alexandria sustained its reputation for many centuries; Rome derived a great portion of its supplies from this source, and as late as the reign of Aurelian we find the manufacture still flourishing (Cic. pro Rabir. Post. 14; Strabo, l.c.; Martial, XI.11, XII.74, XIV.115; Vopisc. Aurel. 45; Boudet, Sur l'Artº de la Verrerie né en Egypte; Description de l'Egypte, vol. IX p213).
There is some difficulty in deciding by what Greek author glass is first mentioned, because the term ὕαλος, like the Hebrew word used in the book of Job (XXVII.18) º and translated in the LXX by ὕαλος, unquestionably denotes not only artificial glass but rock-crystal, or indeed any transparent stone or stone-like substance (Schol. ad Aristoph. Nub. 737). Thus the ὕελος of Herodotus (III.24), in which the Ethiopians encased the bodies of their dead, cannot be glass, although understood in this sense by Ctesias and Diodorus (II.15), for we are expressly told that it was dug in abundance out of the earth; and hence commentators have conjectured that rock-crystal or rock-salt, or amber, or oriental alabaster, or some bituminous or gummy product might be indicated. But when the same historian in his account of sacred crocodiles (II.69) states that they were decorated with ear-rings made of melted stone (ἀρτήματα τε λίθινα χυτὰ καὶ χρύσεα ἐς τὰ ὦτα ἐνθέντες), we may safely conclude that he intends to describe some vitreous ornament for which he knew no appropriate name. The σφραγὶς ὑαλίνη and σφραγῖδε ὑαλίνα of an Athenian inscription referred to B.C. 398 (Böckh, Corp. Inscrip. n150 §50), together with the passage in Aristophanes (Acharn. 74) where the envoy boasts that he had been drinking with the Greek king "ἐξ ὑαλίνων ἐκπωμάτων" decide nothing, especially since in another comedy (Nub. 737) Strepsiades describes a ὕαλος, or burning-glass, as a transparent stone sold in the shops of apothecaries, and we know that any solid diaphanous substance ground into the form of a lens would produce the effect. Setting aside the two problems with regard to glass, attributed to Aristotle, as confessedly spurious, we at least find a satisfactory testimony in the works of his pupil and successor, Theophrastus, who notices the circumstance alluded to above, of the fitness of the sand at the mouth of the river Belus for the fabrication of glass.
Among the Latin writers Lucretius appears to be the first in whom the word vitrum occurs (IV.604, VI.991); but it must have been well known to his countrymen long before, for Cicero names it, along with paper and linen, as a common article of merchandise brought from Egypt (pro Rab. Post. 14). Scaurus, in his aedileship (B.C. 58), made a display of it such as was never witnessed even in after-times; for the scena of his gorgeous theatre was divided into three tiers, of which the under portion was of marble, the upper of gilded wood, and the middle compartment of glass (Plin. H. N. I XXXVI.34 §7). In the poets of the Augustan age it is constantly introduced, both directly and in similes, and in such terms as to prove that it was an object with which every one must be familiar (e.g. Virg. Georg. IV.350, Aen. VII.759; Ovid. Amor. I.6.55; Prop. IV.8.37; Hor. Carm. III.13.1). Strabo declares that in his day a small drinking-cup of glass might be purchased at Rome for half an as (XVI. p758; compare Martial, IX.60), and so common was it in the time of Juvenal and Martial, that old men and women made a livelihood by trucking sulphur matches for broken fragments (Juv. V.48; Martial, I.4, X.3; Stat. Sylv. I.6.73; compare Dion Cass. LX.17).º When Pliny wrote manufactories had been established not only in Italy, but in Spain and Gaul also, and glass drinking-cups had entirely superseded those of gold and silver (H. N. XXXVI.66, 67), and in the reign of Alexander Severus we find vitrearii ranked along with curriers, coachmakers, goldsmiths, silversmiths, and other ordinary officers whom the emperor taxed to raise money for his thermae (Lamprid. Alex. Sev. 24).
The numerous specimens transmitted to us prove that the ancients were well acquainted with the art of imparting a great variety of colours to their glass; they were probably less successful in their attempts to render it perfectly pure and free from all colour, since we are told by Pliny that it was considered most valuable in this state. It was wrought according to the different methods now practised, being fashioned into the required shape by the blowpipe, cut, as we term it, although ground (teritur) is a more accurate phrase, upon a wheel, and engraved with a sharp tool, like silver ("aliud flatu figuratur, aliud torno teritur, aliud argenti modo coelatur," Plin. H. N. XXXVI.66). Doubts have been expressed touching the accuracy of the last part of this statement; but since we have the most positive evidence that the diamond (adamas) was employed by engravers of gems (Plin. H. N. XXXVII.15; Solin. 52; Isidor. XVI.13, 3), and might therefore have been applied with still greater facility to scratching the surface of glass, there is no necessity for supposing that Pliny was not himself aware of what he meant to say, nor for twisting his words into meanings which they cannot legitimately assume, especially since hieroglyphics and various otherº devices are now to be seen on Egyptian vases and trinkets which have been engraved by some such process (Wilkinson, vol. III p105). The diatreta of Martial (XII.70) were glass cups cut or engraved according to one or other of the above methods. The process was difficult, and accidents occurred so frequently (Mart. XIV.115) that the jurists found it necessary to define accurately the circumstances under which p1211 the workman became liable for the value of the vessel destroyed (Dig. 9 tit. 2 s27 §29; see Salmasius ad Vopisc. Saturn. c8). The art of etching upon glass, now so common, was entirely unknown, since it depends upon the properties of fluoric acid, a chemical discovery of the last century.
We may briefly enumerate the chief uses to which glass was applied.
2. Glass Pastes presenting fac-similes, either in relief or intaglio, of engraved precious stones. In this way have been preserved exact copies of many beautiful gems, of which the originals no longer exist, as may be seen from the catalogues of Stosch, of Tassie, of the Orleans collection, and from similar publications. These were in demand for the rings of such persons as were not wealthy enough to purchase real stones, as we perceive from the phrase "vitreis gemmis ex vulgi annulis" (Plin. H. N. XXXV.30). Large medallions also of this kind are still preserved, and bas-reliefs of considerable magnitude (see Winckelmann, I. c2 §27).
3. Closely allied to the preceding were imitations of coloured precious stones, such as the carbuncle, the sapphire, the amethyst, and above all, the emerald. These counterfeits were executed with such fidelity, that detection was extremely difficult, and great profits were realised by dishonest dealers who entrapped the unwary (Plin. H. N. XXXVII.75). That such frauds were practised even upon the most exalted in station is seen from the anecdote given by Trebellius Pollio of the whimsical vengeance taken by Gallienus (Gall. c12) on a rogue who had cheated him in this way, and collections are to be seen at Rome of pieces of coloured glass which were evidently once worn as jewels, from which they cannot be distinguished by the eye (Plin. H. N. XXXVII.26, 33, 75; Senec. Ep. 90; Isidor. Orig. XVI.15 §27; Beckmann, History of Inventions, vol. I p199 Eng. Trans. 3d edit.).
4. One very elegant application of glass deserves to be particularly noticed. A number of fine stalks of glass of different colours were placed vertically, and arranged in such a manner as to depict upon the upper surface some figure or pattern, upon the principle of a minute mosaic. The filaments thus combined were then subjected to such a degree of heat as would suffice to soften without melting them, and were thus cemented together into a solid mass. It is evident that the picture brought out upon the upper surface would extend down through the whole of the little column thus formed, and hence if it was cut into thin slices at right p1212 angles to the direction of the fibres, each of the three sections would upon both sides represent the design which would be multiplied to an extent in proportion to the total length of the glass threads. Two beautiful fragments evidently constructed in this way are accurately commented upon by Winckelmann (I. c2 §22, 23, 24), and another recently brought from Egypt is shown on the frontispiece to the third volume of Wilkinson's work. Many mosaic pavements and pictures (opus musivum) belong to this head, since the cubes were frequently composed of opaque glass as well as marble, but these have been already discussed in p915 of this work.
5. Thick sheets of glass of various colours appear to have been laid down for paving floors, and to have been attached as a lining to the walls and ceilings of apartments in dwelling houses, just as scagliuola is frequently employed in Italy, and occasionally in our own country also. Rooms fitted up in this way were called vitreae camerae, and the panels vitreae quadraturae. Such was the kind of decoration introduced by Scaurus for the scene of his theatre, not columns nor pillars of glass as some, nor bas-reliefs as others have imagined (Plin. H. N. XXXVI.64; Stat. Syl. I.5.42; Senec. Ep. 76; Vopisc. Firm. c3; Winckelmann, I. c2 §21; Passeri, Lucernae Fictiles, p67, tab. LXXI).
6. The question whether glass windows were known to the ancients has, after much discussion, been set at rest by the excavations at Pompeii, for not only have many fragments of flat glass been disinterred from time to time, but in the tepidarium of the public baths a bronze lattice came to light with some of the panes still inserted in the frame, so as to determine at once not only their existence, but the mode in which they were secured and arranged (Mazois, Palais de Scaurus, c. viii, p97; Ruines de Pompéi, vol. III p77; Becker, Gallus, vol. II p20). [Domus, p432.]
7. From the time that pure glass became known, it must have been remarked that when darkened upon one side, it possessed the property of reflecting images. We are certain that an attempt was made by the Sidonians to make looking-glasses (Plin. H. N. XXXVI.66), and equally certain that it must have failed, for the use of metallic mirrors, which are more costly in the first instance, which require constant care, and attain but imperfectly the end desired, was universal under the Empire. Respecting ancient mirrors, see Speculum.
8. A strange story with regard to an alleged invention of malleable glass is found in Petronius (c. 51), is told still more circumstantially by Dion Cassius (LVII.21), and is alluded to by Pliny (H. N. XXXVI.66), with an expression of doubt, however, as to its truth. An artist appeared before Tiberius with a cup of glass. This he dashed violently upon the ground. When taken up it was neither broken nor cracked, but dinted like a piece of metal. The man then produced a mallet, and hammered it back to its original shape. The emperor inquired whether any one was acquainted with the secret, and was answered in the negative, upon which the order was given that he should be instantly beheaded, lest the precious metals might lose their value, should such a composition become generally known.
a The first edition of Smith's Dictionary was in 1842; the first general decipherment of hieroglyphics dates to 1822, and presented many uncertainties and controversies for decades after that. The "Osirtasen the First" of the next sentence is one of the many curious readings of those first days of Egyptology (in this case we owe the reading to Sir John Gardner Wilkinson's edition of the fragments of the Turin Papyrus): the founder of the Twelfth Dynasty is usually referred to today as Sesostris I. His dates are currently put at 1971‑1926 B.C.; and much less certainty, and, to tell the truth, interest, is evinced by modern archaeologists in making the pharaohs correspond to Biblical references.
b Here's a more modern view of the Trivulzio cage cup:
Photo © Carole Raddato 2013, by kind permission.
The full sequence of photographs of which this is a part shows clearly that the article in Smith's Dictionary gets the inscription wrong; it actually reads Bibe vivas multis annis. The cup is currently in the Museo Archeologico of Milan.
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