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The Chinese and Japanese decorate much of their lacquer work,,such as screens, with this shell, and in Cashmere, India, the material is often used for inscriptions on grave stones. Shell fishhooks are common in the South Sea Isles, while in North Africa and in the far East much furniture is inlaid with small pieces of shell. The Chinese and Japanese seem to have a better method of polishing their carvings and their inlay work than have the European workers, and some fine examples of craftsmanship are sometimes seen. The Chinese are especially fond of etching mother-of-pearl, and this they do by using a corrosive acid.

Here, fishing is carried on with the aid of diving apparatus in water of four to 20 fathoms in depth. The pearl, of course, is the first objective of these operations, and when the gems have been extracted, the shells are collected and taken to the base of operations. Most of the shells contain no pearls, but the price obtained for the inferior article is appreciable.
The pearling center is Broome, in Western Australia, and from there most of the fishing boats set out during February. They are out for about three months, after which they return for reprovi sioning, if necessary. The West Australian shell is considered the best for commercial purposes, and it realizes over $700 (£250) a ton. It is large and of a good color, the edges sometimes toning to a silver white or silver gray. Some hundreds of fishers are engaged in pearling, the majority of whom are Chinese and Japanese. The quantity of shells collected varies from year to year; in 1928, 2,212 tons, valued at $963,636 (£345,227) were exported from Australia, but in 1930, the amount was somewhat greater.
In the Persian Gulf, the fishing is carried out by natives, also in February or in April. No modern diving suits or apparatus are used in this area, although these have been offered and provided on many occasions. Here, of course, the precious pearl is found in its most esteemed qualities, and the shell is of very minor importance. The shell, known as lingah from the pearling port of Lingah, is good in quality but rather small, the edges often being dark.
From the coasts of New Guinea, some silver white shells are obtained, and these realize a high price. The yellowish shells are not so valuable. Near to this area (the Aulu Archipelago), the Malays and Chinese fish for pearls, and some fine shells with yellow backs and borders are found. Like other varieties, they are recognized by specific names, and the more highly colored specimens come from the shallower seas since they are more exposed to the sun’s rays than those which are brought up from deeper waters.

Mother-of-pearl, which is familiar to most of us in such forms as bead necklaces, crosses, handles of knives, forks, and spoons, is nothing more than the shell of the pearl oyster. This shell not only encloses the oyster and serves as its home, but it also sometimes contains the precious gem we know as the pearl.
The shell has been slowly and laboriously constructed by the oyster and, as has already been described in the chapter which dealt with the precious pearl, it consists of four distinct layers. The beautiful iridescence for which it is so greatly admired is caused by light interference effects from the minute exposed surfaces of which it is built; if a dilute acid is applied to the nacre, all the calcareous salt may be dissolved, leaving a pellicle of connective tissue which retains its iridescence until it is disturbed.
Pearl shells are found in various areas, including the Red Sea, the Gulf of Panama, the Australian seas, the Persian Gulf, and the Bay of California, but the largest number suitable for working come from the northern and western coastal waters of Australia. This area stretches for about 2,000 miles and runs roughly from Cape York to Shark Bay along the coasts of Queensland, Western Australia, and the Northern Territory. This field came into prominence in the year 1865 when supplies from other areas were decreasing.

England once had the monopoly of tortoiseshell, but for some years, other countries have had a large share in the trade. The Indian islands are now probably the chief suppliers, and the em-poria are Singapore, Manila, and Batavia. The shells find their way to Germany, Italy, England, and France, where they are worked into the different articles which may be seen in most cities. Italy produces most of the finished goods to-day.
Some years ago, the piqu£ gold and tortoiseshell ornaments were very fashionable, but owing to decreased demand, they are now not manufactured. At the London International Exhibition of 1851, a Parisian manufacturer showed an exceedingly fine display of tortoiseshell jewelry. In China and Japan, cups are still made from shell, but in England, little else than boxes, cigarette holders, combs, spectacle frames, and the backs of brushes and mirrors are now made, and even those are in small demand.
As with anything of commercial value, tortoiseshell is now widely imitated, and plastics are used in most instances. Translucent horn, stained to the correct color, is also sometimes used to simulate the natural shell. Modern plastics, of which a very large range may now be had, make excellent superficial substitutes for many opaque and translucent materials since they can be made in any color. Their extensive and growing uses are, however, of more importance in spheres outside jewelry. If heated, the casein plastics char and give off an odor similar to that of burning milk; tortoiseshell fuses to a black mass, which smells like burning hair. Further, the microscope will reveal round, reddish particles in tortoiseshell, which are absent in the plastics. The refractive index of tortoiseshell is about 1.55, and the specific gravity 1.26 to 1.35.

Sometimes tortoiseshell is inlaid with mother-of-pearl, gold, or silver, as may be seen on occasions in brooches, earrings, and hair ornaments. This is carried out by arranging the ornamental pieces on the shell and then pressing them in with the aid of boiling water. The article is then suddenly submerged in cold water and pressure again applied.
Tortoiseshell was regarded as a valuable ornamental material in very early days, and it was then probably more highly esteemed than now since today we have such a wide choice of both natural and artificial substances. The shell was brought to ancient Rome from the East via Egypt, and the Romans used it largely as a veneer on their furniture. According to Pliny, Carvillius Pollio was the first to apply tortoiseshell to ornamental purposes. Strabo, Diodorus, and Pliny all write of boats made from shells of the tortoise, but how these boats were constructed is not described.
Besides being used in the manufacture of toilet articles and jewelry, its most common function, tortoiseshell has been extensively used in the making of Buhl furniture. It was formerly much used as an inlay in cabinets, picture frames, and clock cases. Boule (1642-1732), a cabinet maker in the service of Louis XIV, used this shell largely as a veneer with wood in the making of furniture, and hence the term buhl has since been applied to all similar work.

In general, tortoiseshell is worked in much the same way as is horn. The plates are separated from the bony skeleton of the animal by heat, but care is needed as an excessive heat tends to darken the color. Again, although boiling will soften the shell, prolonged boiling spoils the color. For this reason, salt is often added to the water, but this has the disadvantage of rendering the shell brittle if too strong a solution is used.
A factor which makes the working of tortoiseshell much easier is the facility with which it may be joined together and shaped. Two’pieces may be united by simple pressure alone, but more often a gentle heat is used. In the latter instance, edges are first beveled, scraped clean, and then compressed in a press which is placed in boiling water. The press is tightened from time to time, and in a few hours the joint is complete without injury to color or to texture.
Tortoiseshell may also be molded, and by this means cigarette cases, boxes, beads, and larger articles are produced. In molding, the shell is first cut roughly to size in the flat and then placed in a mold which is lowered in boiling water. In about half an hour, the block may be pressed into the mold, carrying the shell with it. The article is subsequently finished on a lathe. As the shell is fairly expensive, chips and dust are collected and used later; they are softened, pressed together, and molded, but the resulting material is almost opaque and therefore of inferior appearance and value. Coloring matter is also often used in this process.

Tortoiseshell is not obtained from the tortoise, as the name may lead one to believe, but from the hawk’s-bill turtle. The turtle is a group of animals which lives in the sea, or they spend most of their time in the water since their food consists almost wholly of fish and molluscs. Many varieties of turtle are very useful as food and they are regarded by some as great delicacies, but the hawk’s-bill does not come within this class. Its chief value lies in its shell, which consists of thick, horny, overlapping shields or plates. This is the source of the material which we know as tortoiseshell.
There are 13 such plates on the back of the animal (known in the trade as blades); five occupy the center, and four may be found on each side. All overlap each other, the largest sometimes reaching the size of 14 inches by 8 inches, and the weight of about nine ounces. The marginal plates, 24 in number, are commercially of inferior value, but all consist of a horny material which cannot be considered as true shell, although they are distinctly harder, more brittle, and less fibrous than ordinary horn, which they closely resemble.
The thirteen larger plates are called the heart, and the back plates are known as hoofs or claws. The 24 marginal pieces, which have rounded edges, are called feet, or noses. As a rule, these are one-eighth to one-quarter of an inch in thickness, and the shell from an average sized turtle weighs from five to six pounds. The value of this material depends on the richness of the mottled colors and the capacity for a high polish which it takes and rein ins. The most sought after color is the warm, translucent yellow, spotted with rich, brown tints.
The hawk’s-bill turtle may be found in most tropical and subtropical seas, but the brown and light colored shells are imported chiefly from India and China. The finest comes from the Eastern Archipelago, especially from the east coast of the Celebes and New Guinea. The West Indies, Australia, Africa, and the Brazilian coasts are also well known homes of the turtle.

Some mention must also be made of vegetable ivory. This is a kind of palm, known to botanists as phytelephas, but usually called the tagua palm. It is a native of tropical South America, growing wild along the west coast from Panama through Colombia and Ecuador. It is found in damp localities and usually grows apart from other shrubs.
The plant is a palm fern, 10 to 20 feet high, with a short trunk, crowned with large, bright green, feathery leaves. The head is filled with seeds, these being enclosed in a hard covering. The fruit is somewhat similar to a coconut, growing in drupes about the size of a man’s head. The seeds are hard, white, and finely grained, very much like real ivory, and as they ripen, they get harder.
A single plant may have six to eight heads, each weighing about 20 to 25 lbs. Natives gather the matured nuts after they have fallen to the ground and sell them to traders. The American Indians use these nuts or seeds for making small, ornamental articles, but we import them under the name of “corozo nuts,” and use them in the making of buttons, umbrella handles, chess men, counters for card games, and other small articles.
Vegetable ivory may be distinguished from genuine ivory by touching it with concentrated sulphuric acid. The former will show a pink coloring in about ten minutes’ time (which may be removed by washing in water). Real ivory is unaffected. Good imitations of real ivory are made from many of the modern plastics, while a German product is the result of chemically treating coral. This latter largely possesses the properties which render natural ivory so easily workable.

Although ivory carving flourished during the Renaissance, the Nineteenth Century saw its greatest development. All kinds of beautiful articles were produced, and these were enhanced by the addition of suitable gem stones. In a far earlier age, ivory had been used for decorative purposes and numerous references to it occur in the Bible, thus showing that it was regarded as being of great value in those days. It seems to have been used in the deed ration of the Temple. The Ninevah ivories in the British Museum are of very great antiquity, yet they are still in a good state of preservation.
In Europe, Germany, France, and Belgium are now the chief centers of ivory carving and working, but the larger and more intricate pieces which demand unlimited time, patience, and ingenious skill for their execution come from the East. China, Japan, India, and the East Indian Islands all export quantities of carved ivory goods and a wide range of their work, both good and bad, may be seen in many countries. Chinese ivories of outstanding beauty are rare, and the older pieces were never signed by the artist, which makes it difficult to assign a date to them.
In addition to ornamental and decorative articles, ivory is also used in the making of billiard balls, handles of knives and forks and toilet articles, but since the material is affected by extremes of temperature, its practical uses in these directions are limited. Only the best quality may be used in the making of billiard balls, and these are far superior to those made from an artificial material for the latter lack the elasticity of the natural substance. The making of billiard balls requires great accuracy of workmanship. When first cut, ivory is semi-transparent, and as it dries, it becomes much lighter in color and more opaque. Shrinkage also takes place, so tusks are usually first seasoned, as is wood, before being cut.

Hippopotamus ivory is beautifully white arid hard; it is generally covered with a white enamel, and when dried, the tusks often split into two perfectly equal longitudinal halves. The enamel is, as a rule, first removed by acid or by other means before working on the material. Since no large pieces are obtained from this type, it is used in the making of smaller objects, such as umbrella and stick handles.
Walrus ivory is coarser than hippopotamus ivory, and it is fairly rare. It has a nodular appearance when cut and polished, being very dense and uniform in consistency. Tusks are about three feet in length, and weigh from 7 to 15 lbs. Narwhal ivory comes from the single horn of an Artie whale. It is thick, perfectly straight, but it often contains fissures and cracks. The point of the tusk is always very sharp, and the whole tusk, as well as that of the cachalot whale, is very small.
On account of its characteristic properties, ivory lends itself to the art of carving, and many beautiful specimens and collections exist. Jean Coujou, Albrecht Diirer, Michaelangelo and other artists found expression in ivory carvings. Bowls and tankards were once especially favored, but today, all kinds of articles, both useful and ornamental, are made. Figures of animal and human life, if well carved, are greatly admired as are also miniature paintings on ivory, for the natural color of the material resembles that of the human skin. In articles of utility, however, the use of ivory has, in recent years, been largely replaced by many of the synthetic plastics.