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stance, or else through some imperceptible fissures in the soldering, during the few centuries they have lain under ground; and curiously enough the marks made by the successive deposits of the rising liquid on the interior of the glass exactly imitate the natural layers of an Agate. At the sale of Barbetti's collection of Phoenician antiquities, some hollow rims of glass sepulchral urns filled with water, which had doubtless penetrated in the same manner as in the spherical bosses above mentioned, were bought at high prices by credulous antiquaries, who took for granted the truth of the wily Italian's assertion, that they contained a wonderful perfume with which they had been filled at the time of their manufacture. And to increase the prodigy, he pretended that this liquid was of so powerful an odour, that one of these rims having been broken by accident in a room in Paris, all the persons present were immediately driven out by its strength!

JADE.

Jade is a semi-opaque stone of a soapy appearance, and varying in colour from a dirty white to a dull olive. Amulets made of it were believed in the Middle Ages to prevent all diseases of the kidneys; hence the name of the stone from Hijada, the Spanish for "kidney," and its scientific title of Nephrite. Many vases and figures in this material are to be seen in collections, but few of them probably are antique. The sole merit of these works lies in the extreme difficulty of their execution on account of the excessive hardness of the stone, which circumstance greatly recommends it to the Chinese and to their brethren in taste, certain amongst the rich and curiosity-loving of the English collectors. I scarcely believe the stone to have been known to the ancients, from the fact that its popular name is due to the Spaniards or

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Portuguese, who first imported it from the East; for if commonly employed in ancient art,' we should have expected to find it still designated by some Italian corruption of its Latin synonym. Pliny mentions a Syrian stone, the Adadunephros, or "kidney of Adonis;" but as there was also the "eye" and the "finger" of the same personage represented by gems, we may conclude they all owed their names merely to their similarity in form to those parts of the human body. Even had the Jade been known at an earlier period, the ancient love of the beautiful and their correct taste would have prevented their throwing away their labour and time upon so ugly and refractory a material.

JET.

This name is a corruption of Gagates, its ancient appellation; but it was then chiefly used in medicine and in magic, as a means of fumigation. It was also employed for staining pottery an idelible black: "fictilia ex eo inscripta non delentur." Anklets and bracelets are found turned out of it, as well as of the similar substance, Kimmeridge coal, the works of the Roman-British inhabitants of our coasts:2 but the intagli in Jet palmed off upon antiquarians so abundantly within these few years, are known now to be recent forgeries.

1 I have, however, met with one or two intagli of the Gnostic class upon either this stone or else a bad plasma, not to be distinguished from it by the eye.

2 A complete suite of Jet ornaments, comprising two hair-pins with heads composed of pine-cones, almonds, and trefoils, bracelets,

rings, a half-crotalon with the head of Medusa, in all 26 articles, were discovered in two stone-coffins, deposited under the chief entrance of Saint Geréon, Cologne, at the time of the repairs of that church in 1846. They are supposed to have been the ornaments of some priestesses of Cybele.

THE FORMS OF ANTIQUE GEMS.

In the age of Pliny the favourite form was, he says, the oblong, meaning thereby the very long oval in which antique gems are so often to be found. In the next degree of favour stood the lentile-shaped, or a sphere much flattened on both sides, now called a "stone cut en cabochon," or in jewellers' phrase "tallow drop." Lessing has some ingenious speculations as to the general adoption of this form, which is to be seen in fully half the number of intagli existing. He endeavours to show that it facilitated the engraving of the design, and assisted the perspective by bringing the various depths of the intaglio into the same plane. But the most probable motive was, that the projecting surface of the gem forming a corresponding depression in the wax might serve to protect from defacement the impression of the intaglio in that soft material.3

Next in favour came the cycloidal or elliptic shape, a very common one in the intagli of the preceding century; and last of all the circular. Angular stones were disliked, and indeed we never meet with fine intagli cut upon such, for whenever gems of this shape do occur, which is but seldom, they present engravings belonging to the latest ages of the Empire; and such are also octangular. A square antique intaglio I have never met with. Gems with a hollow or irregularly projecting surface were naturally regarded as inferior to those of a flat and even exterior. To understand this remark, it is necessary to have seen in what manner the Romans employed the harder precious stones, as Rubies and Sapphires, and we find that they never attempted to reduce them to any regular shape, but set them retaining their natural form, to which the lapidary had

3 Besides, the protuberant form of ornamental and showy when worn the coloured gem rendered it more on the finger.

contrived to give a certain degree of polish. Hence such a stone, if naturally presenting a regular shape, or that of the original crystal, was much more ornamental than those occurring, as is most usual, in the ungainly form of irregularly rolled pebbles. The most valuable coloured gems, almost as rude (with the exception of a slight polish) as when picked up amongst the gravel of the Indian torrent, may be seen adorning, more by their intrinsic value than by their beauty, the most precious treasures of antiquity, as the Iron Crown, that of Hungary, and the five coronets of the Gothic kings of Spain now deposited in the Hôtel de Cluny.

CHEMICAL COMPOSITION OF GEMS.

Diamond: pure Carbon. Specific gravity, 3.50; hardness = 10. Sapphire nearly pure Alumina. Sp. gr., 4; hardness 10 nearly. Ruby the same, but slightly less hard.

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Emerald: Glucine, 12.5; Silica, 68.5; Alumina, 15.75; Oxide of Chromium, 0.3; Oxide of Iron, 1; Lime, 0.25. Sp. gr., 2.7; hardness

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7.5 to 8.

Jacinth: Zircon, 70; Silica, 25; Oxide of Iron, 0.5. Sp. gr., 4.5 to 4.7; hardness

= = 7.5.

Garnet: Silica, 33.75; Alumina, 27.25; Oxide of Iron, 36; Oxide of Manganese, 0.25. Sp. gr., 4.2; hardness = 6 to 7. Amethyst or Coloured Quartz: Silica, 97.5; Oxide of Iron, 0.75; Alumina, 0.25. Sp. gr., 2.6; hardness = 7.

Turquoise: Alumina, 73; Oxide of Copper, 4.5; Oxide of Iron, 4; Water, 18. Sp. gr., 2.8; hardness = 5.

Lapis-lazuli: Silica, 49; Alumina, 11; Lime, 16; Soda, 8; Oxide of Iron, 4; Magnesia, 2; Sulphuric Acid, 2. Sp. gr., 2.95; hardness, scratches glass.

Calcedony (including Carnelian, Onyx, Plasma): Silica, 84; Alumina, 16. Sp. gr., 2.6; hardness, somewhat greater than Flint.

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Horses of Achilles mourning over the slain Patroclus: Greek. Yellow Sard.

ON THE TESTS OF ANTIQUITY IN GEMS,

AND ON

THE INSTRUMENTS USED BY THE ANCIENT ENGRAVERS.

ON commencing the Second Section of this work, which treats of the Intagli and Camei considered in themselves, it will be a most suitable introduction to the subject, to make a few observations on the two points, forming the title of this chapter, so intimately connected with each other. No definite rules can indeed be given, as nothing but long experience, and the careful examination of large numbers of gems belonging to every period, can supply that almost intuitive perception in the art, so impossible to be acquired in any other manner. The remarks that follow are the result of much thought, and of many years study of antique gems, and of the careful examination of some of the principal European collections.

If we consider the purpose to which intagli were almost exclusively applied, at the time of their execution, namely, that of signets, to be worn set in rings, we shall naturally look with suspicion upon any engraved gems the dimensions of which

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