so-called after its founder Obsidius, four elephants made of which were dedicated by Augustus in the temple of Concord were also known; and a statue of Menelaus, made of the same material, was returned to the Heliopolitans by Tiberius: (24) The opal opalites, or paderos, obtained from India, the largest of which then known, of the size of a hazel-nut, belonging to the senator Nonius, was valued at about £2000, which he would not yield to M. Antony; this stone was sometimes engraved: (25) The adamas, of which seven varieties were known to the ancients, was only used for cutting other gems, or worn rough, but was not engraved, or even faced, the art of polishing it having been discovered by Louis de Berghem in the 15th century. The list of Pliny, indeed, contains many other stones, which have been either confounded with those already described their names having been derived from different sources-or else they are species of the same. Many of these had fanciful names, as (26) the Aromatites of Arabia and Egypt, so-called from its fragrance: (27) The alectorius, worn by the wrestler Milo, so-called from being taken out of the gizzard of a fowl: (28) The aspilates, a fiery stone, said by Democritus to be found in the nest of Arabian birds. In the selection of stones for engraving, the gem-engravers adapted the material to the subject -Bacchanalian subjects were often engraved on amethysts; marine, on beryls; martial, on carnelians, sards, and red jaspers; rural, on green jasper; celestial, on chalcedonies. Superstitious virtues were also attributed to the different varieties of gems thus the amethyst was supposed to protect from the influence of wine; and according to Dioscorides, the jasper was particularly adapted for amulets; and Alexander of Tralles recommends the subject of Hercules engraved on a Median stone, to be worn on the finger as a remedy against the cholic.

The art of engraving precious stones at the earlier periods of the Egyptian monarchy was comparatively unknown, although these people made beads of carnelian, felspar, root of emerald, jaspers, lapis lazuli, amethyst, and other hard stones. For the purposes of seals, however, and for intagli, steatite scarabaei were generally used, and engraved gems are either of the greatest rarity or suspected, till the time of the Ptolemies. A remarkable exception to this rule is a square signet of yellow jasper, engraved with the name and titles of Amenophis II. (about 1450 B.C.) and his horse, in the British Museum. Under the Ptolemies and Romans, the Gnostic gems, called Abraxas, generally of lapis lazuli, blood-stone, and jasper, begin to appear, but these are made by the same process as the Greek, from which they were derived. The Green Jasper Abraxas, Ethiopians, according to with figure of Iao. Herodotus, engraved signets. The same may be said of the neighbouring Phoenicia, which either imitated the cylinders of the Babylonians, or the scarabaei of the Etruscans. In Assyria, the oldest gems are of cylindrical shape, from one to two inches long, and half an inch thick, pierced through their long axis for a cord to attach round the wrist. The earlier ones are of serpentine, the later of the time of Sargon or Shalmaneser, of agate, jasper, quartz, and syenite, engraved with figures of the gods, and the names of their possessors in cuneiform. The inscriptions, indeed, are often difficult to read, but names similar to those of Assyrian and Babylonian monarchs occur,

WAI

one cylinder having a name like that of Nebuchadnezzar. The Babylonian are of the same type, and chiefly of hæmatite, loadstone, steatite, and jasper; have also figures of deities, and the names of deities or the possessors, generally executed in a coarse rude style by the graver. Oval gems, indeed, appear, from the impressions on the clay tablets, to have been in use at the same time; that of cylinders passed to the Persians, under whom the art became much better, and chance has preserved the cylinder signet of Darius I., found in Egypt.

These cylinders were abandoned for conical gems, principally of chalcedony, engraved on the base with figures of deities, in use prior to the conquest of Alexander, and were at a later period, commencing in the 3d c. A.D., followed by hemispherical agate gems, with heads, animals, and Pehlevi inscriptions, generally of a rude and debased style of art. These, again, at a later period, were succeeded by convex stones en cabochon, often garnets, sards, carbuncles, engraved on the upper surface, with rude figures of animals, heads and other devices also, accompanied with Pehlevi inscriptions, and these probably continued till the rise of Mohammedanism in the East, when the art was confined to the engraving of cufic legends on the most valuable of oriental stones, often with a great degree of dexterity. In Judea, the use of signets (see SEALS) prevailed, and the most important known instance is the Urim and Thummim, or breastplate of the high-priest, consisting of twelve precious stones, engraved with the names of the twelve tribes; but no Hebrew engraved stones earlier than the 5th or 6th century are known. Amongst the other oriental nations of antiquity, the Bactrians and early Hindus seem to have exercised the art of engraving on stones, although no works of great merit of these nations have been found, and those of a later age are mere seals engraved with sentences of the Koran, or the names of the possessors, and when smeared with black or coloured inks, were impressed on documents as stamps. Of the other nations of antiquity, the Chinese only have had seals (see SEALS) of crystal, soapstone, porcelain, and other substances, with devices in relief for using as stamps, the subjects being mottoes from poetical and other works.

The Greeks, at the earliest period, are not sup posed to have employed engraved stones for their signets, the earliest rings being of solid metal, such as the legendary ring of Minos; but at a later period, those of Helen, Ulysses, and the legendary one of Gyges, are said to have had engraved stones. Orestes, in the tragedies, is also recognised as the son of Agamemnon by his engraved ring; and Mnesarchos, the father of Pythagoras, who lived about 700 B. C., was an engraver of gems. The earliest instance of an engraved gem is the emerald ring of Polycrates, set in gold or engraved by Theodorus of

strokes, the compositions rarely contain more than two figures. Artists of great merit, as Dioscorides, Apollonides, and Chronios flourished at this age. The names of the artists who engraved the gems, and of the proprietors, are occasionally found upon them. The devices were various: Augustus had first a sphinx, then his portrait engraved by Dioscorides; Nero, Apollo and the Muses; Galba used first a dog, subsequently the head of Augustus. After the Antonines, indeed, the art rapidly declined, and portraits after Severus are rare, although even that of Mauricius is said to occur. Sard Portrait of Caligula. At the middle period of the Empire, the work is exceedingly rude, often merely scratched out by a diamond point in carnelians, jaspers, and garnets. Some works, indeed, of the later or Byzantine period exist, but they are of poor merit and execution, and the subjects are taken from Christian subjects. The gems of this later period are sometimes square, generally, however, the long or convex oval. The camei, or gems in relief, the ancient ectypa sculptura, appear at the period of the Roman Empire. This term camei, of uncertain origin, is applied to engravings on stones of two or more layers, such as the onyx or sardonyx, and niccolo, and is different from the relief-gems cut out of stones of one colour. Ancient camei, indeed, are of the greatest rarity, and are not older than the imperial days of Rome. The smaller ones were used for rings; the larger, which are often perforated, are supposed to have been worn in the armour or dress, phalera. They were worked out with the diamond point; chiseled, so to say, out of the stone; and have, when examined, a rough appearance. The most remarkable ancient camei known are those of the Vienna collection, supposed to represent the apotheosis of Augustus, on which are Augustus, Jupiter, and Rome enthroned, the Earth, Ocean, Abundance, Germanicus, Victory, a triumphal car, Tiberius, and German captives; another, in the same collection, with Ptolemy II. and Arsinoe, the great cameo in the Bibliotheque at Paris, representing the apotheosis of Augustus; another in the collection of the Netherlands; and a fourth in the Vatican; a cameo at St Petersburg, one foot long, and another, eight and a half inches wide by six inches high, in the Marlborough collection, with the heads of Didius Julian and Manlia Scantilla. At a later period, the art had considerably declined, and the Christians of the later days of the Empire were content with engraving inscriptions on camei. These gems were principally worn as objects of attire, and Heliogabulus is said to have placed even intagli in his shoes. The names of artists are rarely found upon camei; a celebrated one of the Marlborough collection, indeed, has the name of Tryphon, but there is considerable doubt about the authenticity of the inscription.

Samos about 740 B.C.; while the laws of Solon against counterfeiting signets shew that they may have been in early use. At the period of the Persian war they were by no means uncommon. Later, the writings of the Platonists and Stoics constantly allude to gems, and the flute-player Ismenias, 437 B. C., purchased an emerald engraved with a figure of Amymone. Still later, the poet Eupolis instances the extravagant prices given by the Cyrenæans for engraved stones in rings. Yet it Greek Sard, with is doubtful if any real Greek Indian Bacchus. intagli earlier than the war of Peloponnesus can be identified, those hitherto cited in low relief, enclosed in a guilloche or engrailed border, and of a hard and stiff style of art, having been probably cut from the bases of scarabaei of Etruscan work. At a later period, their use was universal, and the names of celebrated engravers, such as Pyrgoteles and Apollonides, are known, the first named having the privilege of engraving the portrait of the monarch, Alexander the Great: Ptolemy V., presented as a most precious gift his portrait engraved on an emerald to Lucullus; and Cleopatra had a gem with Bacchus. The style of engraving of this age is fine and noble, the hair indicated by fine wiry lines; the subjects are generally heroic, but busts and portraits of divine, regal, and historical personages appear. Sards, amethysts, and jacinths were in use. Contemporaneous with the Greek school, if not earlier, was the Etruscan, consisting of scarabs entirely carved out of sard, carnelian, agate, with engraving often of exquisite work, but generally harsh, and sometimes of severe style, with subjects derived from the earliest Hellenic myths, and occasional inscriptions in the Etruscan language, the names of the personages represented, seldom more than one figure appearing on the gem. The subject is surrounded with a guilloche or engrailed border, and the scarabs were pierced through their long axis, to set as rings or to wear as other objects of attire. Similar scarabs, but of green jasper, and of Phoenician workmanship, have been found in Sardinia. These gems probably were made from the beginning to the middle of the 3d c. B. C., when Etruria fell into the power of the Romans, who derived their engraved stones from the Greek successors of Alexander, as engraved rings, with their subjects, are mentioned at the close of the republic, the device of Scipio Africanus being a head of Scyphax; that of Sylla, the submission of Jugurtha; of Pompey, a lion carrying a sword; and of Cæsar, Venus armed with a dart. So great had the passion for these charming little works of art increased, that Scaurus, the step-son of Sylla, had even a collection of gems, dactyliotheca. Pompey sent the collection of Mithridates as an offering to the Capitol; and Cæsar, to outvie his great competitor, presented six such collections to the shrine of Venus Genetrix; and Marcellus another to the cella of the Palatine Apollo. At the commencement of the Empire, the portraits follow the costume and art of the period; the hair is expressed by broad

Carnelian Etruscan Scarabæus:
Centaur and Deer.

The subjects of ancient gems embrace the whole circle of ancient art, and follow the laws of its development, animal forms being succeeded by those of deities and subjects derived from the battles of Greeks and Amazons and Centaurs, the exploits of Hercules, and other heroes; then by scenes from tragedians and later myths; and, finally, by portraits, historical representations, and allegories. The inscriptions consist of the names of deities, heroes, and subjects; dedications to deities; the names of artists, sometimes in the genitive case, but often accompanied with the verb epoci,

'was making' (the affected imperfect used after the time of Alexander the Great); addresses to individuals; gnomic or other sayings, indicating that the gems are amulets against demons, thieves, and various evils; or charms for procuring love; the names of the possessors, and sometimes addresses, occasionally even distichs of poetry, and various mottoes. These inscriptions were often added by subsequent possessors, and are not of the age of the gem itself. The number of artists, although very considerable, does not exceed 100 authentic names; and the true names are supposed to be distinguished from false ones by being placed at the side of the composition in very small letters terminating in dots; but even these have been successfully imitated by modern artists, and the greatest criticism and learning have been displayed to detect real ancient names by their orthography and palæography. The number of false antique stones produced by eminent engravers since the revival of the arts, has rendered the diagnosis of gems so difficult, that no branch of archæology requires greater judg. ment. All gems of high artistic merit and great finish are suspected, especially those with groups of many figures, regular edges, and polished faces, or too great a polish in the deep parts. Coarser imitations have been produced by backing pastes or coloured glass (see GEMS, IMITATION) with stones, and mounting them in rings, so as to pass for a gem. The appearance of wear and friction has been produced by introducing them for awhile into the gizzards of turkeys, or in pierced boxes plunged in the beds of rivers. The judgment upon gems can be, however, only matured by a careful study and familiarity with all branches of ancient art. The coarser imitations of pastes, the tongue, the file, and the graver will detect; but old gems re-engraved, or new compositions invented, require the most careful survey. The place or circumstance of discovery is only a feeble guarantee against deception, the commerce in false antiques being successfully plied upon the unwary even in the far East.

The chief implement used by the ancient engravers appears to have been made by splitting diamonds into splints (adamantis crusta) by a heavy hammer, and then fixing these points like glaziers' diamonds into iron instruments, with which the work was executed by the hand (ferra retusa). The drill, terebra, was also extensively used for hollowing out the deeper and larger parts of the work, and emery powder, the smaris or Naxian stone, for polishing. The so-called wheel, a minute disk of copper, secured to the end of a spindle, and moistened with emery powder or diamond dust, and driven by a lathe, does not appear to have come into use till the Byzantine epoch. It has been conjectured that the artist used lenses of some kind, or globes filled with water, to execute his minute work; but the ancient, like the modern engraver, rather felt than saw his way. All these processes were not employed by the same artist, for besides the engraver (scalptor cavarius, dactyliographus), a polisher (politor), not to mention arrangers (compositores gemmarum), and merchants (gemmarii, mangones gemmarum) who drove a flourishing trade in emeralds and pearls and engraved stones in the days of Horace.

there was

The general fall of the arts at the period of the Byzantine Empire, seems to have been accompanied by the decline of the art of engraving on gems; and the Merovingian and Carlovingian monarchs were obliged to use antique gems, instead of those engraved by the artists of their day. Rockcrystals, however, were engraved in a Byzantine style of art, with sacred subjects, in the 9th c.; but

the art was all but lost till the rise of Lorenzo de Medici, when Giovanni delle Corniole at Florence, and Domenico dei Camei at Milan, worked under his patronage. A subsequent school of gemengravers originated with Pietro Maria de Pescia, who worked for Leo X.; the chief representatives of the school are Michelino, Matteo de Benedetti, the celebrated painters Francia, M. A. Moretti, Caradosso of Milan, Severo of Ravenna, Leonardo da Vinci, J. Tagliacarne, Bernardi of Castel Bolog nese, who died 1555, celebrated for a Tityus copied from M. Angelo. These were succeeded by Matteo del Nassaro of Verona, who worked for Francis L, and produced a crucifixion on heliotrope, so that the red spots seemed drops of blood issuing from the wounds of Christ; Caraglio, who flourished in Poland in 1569; Valerio dei Belli, who chiefly employed rock-crystal; Marmita, Domenico di Polo, Nanni, Anichini of Ferrara, and Alessandro Cesari, celebrated for a cameo head of Phocion; Dei Rossi, a Milanese, engraved the largest cameo of modern times; Jacomo da Trezzo, celebrated for his portrait, is said to have been the first to engrave on the diamond in 1564-an honour disputed, however, by Birago, another Milanese, both artists having been in the service of Philip II. of Spain, who made a portrait of Don Carlos and the arms of Spain on this gem.

The art, which had declined at the close of the 16th c. in Italy, flourished in the 17th c. in Germany under Rudolph II., for whom Lehmann engraved at Vienna; and in France, where Coldoré worked for Henri IV. and Louis XIII. In the 17th c., Sirletti, who died at Rome in 1737, excelled in portraits, and copied antique statues with great excellence. The two Costanzi are celebrated in 1790, one for the head of Nero on a diamond. Rega of Naples is said to have come nearest to the antique. Natter of Nuremberg, who died in 1763, is celebrated for his intagli; Guay and Barier were celebrated in the French school; and the English produced Reisen, who died 1725; Claus, who died 1739; Smart, celebrated for the rapidity of his works; and his pupil Seaton, a Scotchman, who engraved portraits of the great men of his day. The greatest artist of the age, however, was Natter. Of the subsequent Italian school, Ghinghi, Girometti, Cerbara, Bernini, and Putenati are much praised. The 19th c. produced many good English engravers, as Marchant, Burch, Wray, and Tassie; while Pistrucci, celebrated for his charming cameo, Weigall, and Saulini, who made intagli, complete the list of modern gem-engravers.

The

With respect to ancient gems in the dark and middle ages, they were preserved in shrines, châsses, and other ecclesiastical vessels in which they were set, the passion for collecting them as works of art having commenced with Lorenzo de Medici, who formed the Florentine collection, and had his name incised on his gems. The large camei of the European collections, however, appear to have been brought by the Crusaders from the East. French collection dates from Charles IX., and was augmented by the successive kings of France; it is very rich in gems of all kinds; that of Berlin containing the united cabinets of the Elector of Brandenburg and the Markgraf of Anspach, collected by Stosch, consists of nearly 5000 stones. The Vienna collection, far less numerous, is remarkable for its large camei. In England, the collection of the British Museum, collected originally by Townley, Hamilton, Payne, Knight, and Cracherode, consists of about 500 stones, some of great beauty and merit, but is very poor in camei. The private collection of the Duke of Devonshire, formed in the last half century, comprises upwards of 500 intagli

and camei, including some of the finest known. The Marlborough, still more numerous, comprises many fine camei and intagli, and numerous works of the renaissance. The Pulzky collection, now in Italy, contains many rare and choice intagli. A celebrated collection, the Poniatowsky, formed upon the base of the old collection of Stanislaus, last king of Poland, was so filled with forgeries by its last possessor, executed by Roman artists with inscriptions by Diez, that it entirely lost its value on dispersion. The Hertz collection, the last great one sold, was remarkably rich in fine Etruscan scarabæi and other intagli. There are probably about 10,000 gems reputed to be antique. Yet these are only a mere instalment of those formerly existing. The immense value placed by the ancients on their gems, may be seen by the scabbard of Mithridates, valued at 400 talents, or £7572; the pearl given by Julius Cæsar to Servilia, worth £4800; that swallowed by Cleopatra, valued at £5000; and the pearls and emeralds worn by Lollia Paulina, wife of Caligula, valued at £320,000-all the spoils of provinces and the heirlooms of her family. These, indeed, were probably not engraved, but in modern times great sums have been paid to celebrated engravers, as much as £800 for one cameo.

Although the acquisition of gems is too costly for private individuals, impressions in glass, called pastes (see GLASS), in sulphur, gutta percha, or plaster of Paris, can be easily obtained, and they answer almost all the purposes of study. Some ancient impressions in terra cotta, indeed, exist, and the poorer classes of Greece and Rome were content with glass pastes. The value of antique gems, owing to the great difficulty of discerning those really so, has considerably declined in this country, and even their authority is very cautiously cited by archæologists. The principal writers of antiquity who treated of gems are, Onomacritus or the Pseudo-Orpheus, Dionysius Periegetes, Theophrastus, and Pliny, whose chapter is compiled from antecedent Greek and Roman authors. Isidorus, 630 A.D., gives an account of the principal stones; so do Psellus and Marbodus in the 11th c.; Mariette, Pierres Gravées (4to, Paris, 1750); Raspe, Catalogue des Empruntes des Pierres Gravées (4to, Lond. 1757); Millin, Introduction à l'Etude des Pierres Gravées (12mo, Paris, 1796); Krause, Pyrgoteles (8vo, Halle, 1856); Koehler, Ueber die Geschnittene Steine (8vo, St Petersb. 1851); King, Antique Gems (8vo, Lond. 1860).

GEMS, ARTIFICIAL. Ever since the chemical composition of our most valued gems-the diamond, ruby, opal, &c.-has been known, attempts have been made, with more or less success, to reconstruct them in the laboratory by the influence of intense heat, electrical action, &c. Amongst the most successful workers in this field, we may mention Ebelmen,* Despretz, Sainte-Claire Déville, and Becquerel.

There are at present no reasons for believing that diamonds of any appreciable size will be formed artificially; Despretz has, however, succeeded, by intense voltaic action, in obtaining minute, darkcoloured crystals of carbon.

Boron, which was discovered simultaneously in 1807 by Davy in England, and by Gay-Lussac and Thénard in France, was first exhibited in a crystallised form by Wöhler and Sainte-Claire Déville. They have not, however, succeeded in obtaining perfectly pure crystals. The different tints which they exhibit are due to the presence of small quan

* Ebelmen's memoirs on this department of chemistry are contained in the first volume of Salvetat's Recueil des Travaux Scientifiques de M. Ebelmen. Paris, 1855.

tities of carbon in a crystalline state (the same condition in which it occurs in the diamond) and of aluminium. It is not impossible that in the discovery of crystallised boron, we may have advanced a step towards the artificial production of the diamond. The boron crystals possess a brilliancy, hardness, and refractive power scarcely inferior to those of the diamond.

one

Sainte-Claire Déville and Caron have published a very important Memoir in the Comptes Rendus (1858, vol. xlvi.), in which they describe various processes by which they have succeeded in obtaining small crystals of white and green corundum, rubies, sapphires, &c. By the action of the vapours of fluoride of aluminium and boracic acid on another, they obtained crystallised alumina (corundum) in large, but thin crystals, some of which were about 4 of an inch in length, and which in their hardness, and in all their optical and crystallographic properties, resembled natural corundum. When a little fluoride of chromium was added, a similar process yielded violet-red rubies of a perfectly natural tint; with rather more fluoride of chromium, blue sapphires were yielded; and with still more of this ingredient, green corundum was obtained, presenting the natural tint of the variety known as ouvaroffite. A mixture of equal equivalents of the fluorides of aluminium and glucinum, when similarly acted on by boracic acid, yielded crystals of chrysoberyl or cynophane, which, although very minute, were perfect in their form, and in all respects resembled the natural crystals. The action of fluoride of silicium on zirconia yields small crystals of zircon or hyacinth (Zr2O,,SiO3); and by the action of silicic acid on a mixture of the fluorides of aluminium and glucinum, hexagonal plates of extreme hardness were obtained, which in some respects resembled emerald (which they were attempting to form), but were not identical in composition with that gem.

The latest researches on this subject are those of Becquerel in the Comptes Rendus (1861, vol. liii. p. 1196). After having for many years tried to obtain gems from solutions of silicates, and by feeble electric currents, he now uses intense currents, with high tension, and in this way has succeeded in obtaining opals, &c.

GEMS, IMITATION, or Pastes, Pierres Précieuses Artificielles, French imitations of the precious stones, are made of glass specially prepared. It differs from ordinary glass in its greater density; at the same time it is made with the greatest possible amount of transparency and purity. Its composition, generally, may be said to be silica of very pure quality, probably quartz crystals, potash, and oxide of lead; but the exact proportions are varied almost by every maker, and each has a secret ingredient or two to add.

The colours employed are usually the same as those used for colouring ordinary ornamental glass, but upon their careful admixture, and upon the skilful cutting to represent the crystalline form of the real gem, the success of the manufacture chiefly depends. By some persons, the cutting is carried to such a marvellous perfection, that their work would deceive the eye of most ordinary judges, when well set and foiled, or backed with silver or tinfoil. See FOIL

The glass used for artificial gems is very generally called strass, from the name of a German who claimed the invention. But if we seek the real inventor of factitious gems, we must go far beyond the time of Strass, for we find Pliny describing, under the name of gemmæ vitrea, certain imitations of precious stones which were known in his time, some of which were certainly made of coloured