The Greeks—who were acquainted with it at least as early as the time of Homer—gradually introduced ivory as a material for sculpture. In certain forms of combination with gold, it gave origin to the art of chryselephantine sculpture, so called from the Greek primitives, gold and ivory. This art, which was perhaps more luxurious than tasteful, was introduced about six hundred years before the Christian era; and it was much admired for its singular beauty. It was not, however, till the days of Phidias that it attained to its full splendour. Two of the masterpieces of this sculptor—the colossal statues of Minerva in the Parthenon at Athens and the Olympian Jove in his temple—were formed of gold and ivory. The Minerva was forty feet high, and the Olympian Jupiter was one of the wonders of the world. In the latter of these, the exposed parts of the figure were of ivory, and the drapery of gold. It was seated on a throne elaborately formed of gold, ivory, and cedar-wood; it was adorned with precious stones; and in his hand the god sustained an emblematic figure of Victory, made of the same costly materials.
The Romans used ivory as a symbol of power; but they applied it practically to an infinite variety of purposes. Their kings and magistrates sat on ivory thrones of rich and elaborate construction—an idea received from the Etruscans. The curule chairs of ivory and gold that belonged to the office of consul, together with the sceptres and other articles of similar description, were all of Etruscan origin. The libri elephantis were tablets of ivory, on which were registered the transactions of the senate and magistrates; the births, marriages, and deaths of the people; their rank, class, and occupation, with other things pertaining to the census. The Romans also applied this material to the manufacture of musical instruments, combs, couches, harnesses of horses, sword-hilts, girdles. They were acquainted with the arts of dyeing and incrusting ivory, and they also possessed some splendid specimens of chryselephantine statuary. Ancient writers, indeed, mention no fewer than one hundred statues of gold and ivory; but they furnish us with no particulars of the mode of executing these colossal monuments of art in a substance which could only be obtained in small pieces. A head, smaller than the usual size, a statue about eight inches in height, and a bas-relief, are the only specimens that exist in the present day.
After the fall of the Roman Empire, the taste for ivory ornament became almost extinct. There were some periods, however, in the early part of mediæval history when this material was not forgotten: when the caliphs of the East formed of it some of the beautiful ornaments of their palaces; when the Arabian alchemists subjected it to the crucible, and so produced the pigment ivory black; when a Danish knight killed an elephant in the holy wars, and established an order of knighthood which still exists; when Charlemagne, the emperor of the West, had ivory ornaments of rare and curious carving.[3] It is, however, at a period subsequent to the return of the crusaders that we must date the commencement of a general revival of the taste in Europe. It would be interesting to trace the steps by which ivory regained its place in the arts and commerce of nations; but on this point we must not linger. From the low countries it spread to the far North. Its relations with art and beauty soon became widely recognised; the growing luxury of the Roman pontificate encouraged its applications; and towards the end of the fifteenth century it was extensively employed as an article of ornament and decoration in every country and court of Europe. The Portuguese were the first to revive a traffic with Africa which had been dormant for upwards of 1000 years. It was originally confined to the immense stores of ivory which the natives had accumulated for the purposes of their superstition; but these soon became exhausted, and the inexorable demands of European commerce once more prompted the destruction of the mighty and docile inhabitant of the wilderness. Elephant-hunting became a trade; and a terrible havoc was commenced, which has been unremittingly pursued down to the present time.
The term ivory, originally derived from a Greek word signifying heavy, is indiscriminately applied to the following varieties of osseous matter:—
1. The tusks and teeth of the elephant.—Naturalists recognise two species of elephants—the Asiatic (Elephas Indicus) and the African (Elephas Africanus.) The former of these species is indigenous to the whole of Southern India and the Eastern Archipelago; but the largest and most valuable Indian elephant is that of Ceylon. The second species is found throughout the whole of Africa; and on the banks of the great rivers and lakes of the unexplored regions of the interior, hordes of the finest African elephants are supposed to wander in security. It was until very recently believed that the Asiatic elephant yielded the largest teeth, and those imported from Pegu, Cochin-China, and Ceylon, sometimes weighed 150 lbs. Specimens, however, have been obtained from the interior of Africa of much greater weight and dimensions. Mr Gordon Cumming has in his collection a pair of teeth taken from an old bull elephant in the vicinity of the equator, of which the larger of the two measures 10 feet 9 inches long, and weighs 173 lbs.; and Mr Cawood, who resided thirty years at the Cape, has another pair in his possession measuring 8½ feet each, and weighing together 330 lbs.
Besides these contemporary races of elephants, the market is extensively supplied by the fossil ivory derived from the tusks of the great mammoth or fossil elephant of the geologist. The remains of this gigantic animal are abundantly distributed over the whole extent of the globe. They exist in large masses in the northern hemisphere, deeply embedded in the alluvial deposits of the tertiary period. Humboldt discovered specimens on some of the most elevated ridges of the Andes; and similar remains have been found in Africa. In the frozen regions of the far North, surrounded by successive layers of everlasting ice, the fossil ivory exists in a state of perfect preservation, and it constitutes indeed an important article of commerce in the north of Europe.
2. The teeth of the hippopotamus, or river-horse.—These, under the inappropriate term of 'sea-horse teeth,' supply the most suitable ivory for the dentist. In addition to twenty grinders, the animal has twelve front teeth, the outer on each side of the jaw being the largest and most prized. This ivory is much harder, closer in the grain, and more valuable than that of the elephant. It is remarkable, moreover, for the extreme hardness of its enamel, which is quite incapable of being cut, and will strike fire with a steel instrument. The large teeth of the hippopotamus weigh on the average 6 lbs., and the small ones about 1 lb. each. Their value ranges from 6s. to 40s. per lb.
3. The teeth of the walrus, or sea-cow.—These are nearly straight, and measure from 2 feet to 2½ feet in length. The exterior portion of the tooth possesses a much finer grain and texture than its core, which in appearance and properties bears a close resemblance to ordinary bone. Of a yellowish cream-colour and mottled, this ivory is much less valuable than the teeth of the hippopotamus. It is seldom applied in our day to other than dental purposes; but its antiquity is interesting. The Scandinavian relics of the eleventh and twelfth centuries, with which our museums are so profusely enriched, are for the most part formed of the teeth of the walrus. The elegant spiral horn of the narwhal or sea-unicorn also produces ivory of a superior quality. It is not to any great extent applied to useful purposes, but is more frequently preserved in museums and collections as a beautiful natural curiosity.
The tusks and teeth of the elephant—the latter, for the sake of distinction, are termed grinders—are formed after the ordinary manner of the teeth of animals. The organism which converts the earthy constituents of the blood into cellular tissue and membrane, contributes in the same way to form the teeth by the successive deposition of layer upon layer of the soft vascular pulp. The marks of these depositions, or laminæ, are clearly distinguishable in the longitudinal striæ of the section of a tooth. Mr Corse Scott states that the Indian elephant has only ten or twelve laminæ in the tooth, while that of the great mammoth has twenty-four, besides having a much more regularly disposed enamel. The tooth is hollow about half-way up, but a very small tubular cavity is visible throughout its entire length. This, sometimes called the nerve, is in reality the apex of successive formations in the process of growth. The grinders are seldom used in the arts. They are of a different texture, the laminæ more loosely combined, and possessing a tendency to separate, which renders them unfit for nearly all useful purposes. Ivory has the same chemical constitution as ordinary teeth—that is, cartilage united to such earthy ingredients as the phosphate of lime.
But it is very remarkable that the fossil ivory of the mammoth, and specimens of the historic period of Pompeii or Egypt, contain sometimes as much as 10 per cent. more of fluoride of calcium than the ivory of the present day. We apprehend, however, that this property—first investigated by Dr George Wilson—may be derived from long-continued contact with earth, since fluoride of calcium is the chief ingredient in the enamel or exterior portion of the tooth. Ancient ivory, having thus gained in its inorganic bases, becomes deficient in the gelatinous constituents necessary to its preservation. We recently had a singularly beautiful application of the knowledge of this principle in the case of the ivory specimens sent from Nineveh by Mr Layard. On their arrival in England, it was discovered that they were rapidly crumbling to pieces. Professor Owen recommended that the articles should be boiled in a solution of albumen, which was done accordingly, and the ivory rendered as firm and solid as when it was first entombed.