The secrets of the Eastern dye-pot are responsible for the unrivalled beauty and durability of the Oriental rug. These secrets of extracting coloring matter from roots, leaves, flowers, barks, and various other vegetable and animal products by a process of boiling, fermenting, etc., were guarded religiously and descended from father to son, many of them having been lost as the family became extinct. Each dyer or family of dyers has some peculiar and secret method of producing certain shades.

Our great knowledge of chemistry has aided us little in our effort to duplicate and produce certain colors which the Orientals produced with the simplest ingredients and without any knowledge of chemistry whatever. Every kind of plant from which dyestuff is obtained is a product of geographic environment, the quality of which depends upon certain conditions of climate and soil. For this reason those of one locality may be superior to those of another. On the other hand it must not be forgotten that there are many classes of vegetable dyes which are not scientifically or honestly made.

After the wool has gone through the washing process and dried it is dipped into one or more pots, according to the shade desired, for a certain length of time, when, without being wrung out, it is hung up over the dye-pot to drip and after being washed once more in cold water it finally is spread out in the sun. Even when the same process is followed each time it is seldom that two bunches of material dyed have exactly the same shade, as the density of the dye and its shade differs somewhat with each dip of wool from a previous pot. This probably accounts in part for the innumerable shadings seen in the rugs of certain localities. Formerly the dyers employed as mordants, valonia, pomegranate rind, sumac, and the barks of certain trees, but in some districts of late they use alum. This, with the lime solution in which the wool is washed before dyeing to increase the brilliancy of the dyes, makes the yarn brittle and lessens its wearing quality. Most vegetable dyes fade, but they fade into softer and more pleasing shades. The best colors for service are, as a rule, the blues, yellows, and reds, all of which improve greatly with age. The browns are apt to lose their lustre, while the blacks, which are really mineral, being made by the action of vinegar on iron shavings, seem most corrosive and gradually eat the wool. Many of the antiques you will find in a splendid state of preservation with the exception of the black, which has eaten the pile down to the warp threads. Natural colored black and brown wools and brown camels' hair are frequently used and they are, of course, durable.

There is no doubt that the increasing demand in this country for the Eastern rug, together with the Russian influence in the Orient, tends towards more hasty commercial methods of manufacture and is, to a great extent, responsible for the introduction there of aniline dyes. The coal tar products have been readily accepted by the Eastern dyers, as they are cheaper, more easily used, and offer a greater number of brilliant shades, all of which appeal very much to the Oriental taste.

The aniline dyes are more commonly used through Asia Minor and, to some extent, in the Caucasus and even in Persia. In 1903 a law was enacted by the Persian government forbidding the importation of chemical dyes and seizing and destroying all fabrics in which they were used. It was also decreed that a dyer found guilty of using them would have his right hand cut off. The government has never been very strict in enforcing this law, else there would be at the present time many one-handed men in Persia.

As there is no such law in Asia Minor, fully seventy-five per cent. of the rugs now imported from that country are aniline dyed. The Kurdistan, Khorasan, and Kirman products, as well as those made by the Nomads in the Fars district of Persia, have been particularly free from outside influences and as a rule are honestly dyed.

The nomadic life of the Kurds in former times enabled them to gather plants more easily and so they were able to obtain good vegetable dyes. Now that they do not roam as much the result is, less vegetable and more aniline dyes. Formerly also, the best wool only was used by the Kurds for the making of rugs and the women chose only that which they knew would take the colors well. Now the men sell the best part of the wool and the women use what is left and press aniline dyes into service to hide any possible defect.

Some of the coal tar products will resist light, water, and air even better than many of the vegetable pigments, but the former have a tendency to make the wool fibres more brittle so that they break easily, while the latter preserve the wool and lengthen the life of the fabric.

Each nation uses to a large extent its favorite color, thus the Persian is partial to the dark greens and yellows, the Turk to the reds, and the Armenian to the blues. Asia Minor and Persia being countries of intense sunshine, in which the colors of the sky and land are most pronounced, the neutral tints and hues make little impression on such surroundings and are therefore little used. All the rug making people use more or less yellow, blue, orange, red, ruby, and green, excepting the Turk, who regards the latter as a sacred color and not to be trodden on. He therefore seldom uses it in any but those of the prayer design.

An expert can often distinguish between an aniline dyed rug and a vegetable dyed one merely by feeling of it, as the coal tar product robs the wool of its oil, making it stiffer, harder, and dryer. Another way to differentiate is to examine some of the white which lies next to some bright color like blue, red, orange, or green and see if it has become tinted with the brighter color. If not, wet the two and after they dry see if the white has taken any of the other color. If so it is probably aniline. In the Orient they use a string of amber beads with which to test the dyes. The beads are drawn over the surface of the rug so that the colors reflect through them. If aniline they are said to have a cloudy appearance, while if vegetable they have a clear wavy appearance. If there is any knowledge imparted by this test it certainly is only in the hands of the experienced. A vegetable dye will fade into a lighter tone of itself, while in a chemical dye some one of the colors used to make up the composite color will disappear. For instance a blue, which has been used with yellow to make green, may entirely disappear, leaving the yellow; thus in the aniline product the surface will show the changed color and the original color will show down next to the warp, while in the vegetable dyed product there will simply be two shades of the same color.

Weavers frequently choose colors according to their symbolic significance, so that they work into their rugs a sort of poetry which only the initiated can read. Thus to the Persian, the Chinese, and the Indian Mohammedan, white is an emblem of mourning; green is regarded by the Mohammedan as a sacred color and denotes immortality; blue to the Persian means air, while to the Mongolian it means authority and power; black denotes sorrow, evil, and vice; red denotes joy, happiness, life, truth, virtue, and sincerity; yellow is a Chinese color for royalty; orange is the Buddhist and Mohammedan color for sorrow, and rose for divine wisdom. The following is a list of some of the most common Oriental colors with a short description of the sources from which they are derived:

Red.—The best and most lasting is the rich carmine known as Kermes and consists of dried insects which live on a species of oak tree. These insects are collected in the month of June and are killed by being exposed to the vapors of acetic acid evolved by heating vinegar. Kermes was known to have been used in Syria in the time of Moses, and is probably the most lasting and most preservative of all dyestuffs. Of late years, however, it has been to a large extent supplemented by cochineal, which is more brilliant. Madder root, ground and boiled, is the basis of a multitude of reds and is also noted for its fastness. From it can be obtained many degrees of red from pink to intense scarlet, but the shade most commonly used by the Persians of to-day is obtained by combining madder with alum and grape juice. Although cochineal is used considerably by Eastern dyers, it is really a modern dye, being obtained from dried insects which are found on the cacti of Mexico. It gives soft, beautiful reds, is absolutely fast and is very expensive. With bichromate of potash it gives purple; with sulphuric acid, crimson and scarlet, and with madder, cherry and various shades of pink. One of the best, richest and most lasting vermilions was made by a secret process from sheep's blood, but the secret has long since been lost. In recent years many reds have had as a basis the dye woods, such as Campeachy wood, Brazil wood, and others. They are sometimes obtained from onion skins, ivy berries, beets, and other plants, but these latter pigments are not as enduring as those previously mentioned.

Blue.—Indigo dissolved in sulphuric acid, to which is added alum, forms a basis of most blues and was used long before the Christian era. It is obtained from the leaves of various specimens of Indigofera which are cultivated largely in India. The deep Persian blue is obtained by applying indigo over madder. It can be compounded with almost any other dyeing material known and it is by this mixing process that beautiful violets, porcelain blues and pinks are obtained. A superb dark blue found in some of the antique Persian rugs has been in disuse for nearly a half century. The secret of making it seems to have been lost and no one has been able to reproduce it.

Green.—Indigo in combination with one of the yellows furnishes most of the greens. With buckthorn it produces Chinese greens, both bright and dull.

Brown.—Browns are most frequently obtained by mixing madder with yellow or by dyeing with madder over yellow. Valonia, catechu, gall-nuts, and the green husks of walnuts also enter largely into the making of browns.

Yellow.—The principal yellows are obtained from the Persian berries, from turmeric, from saffron and sumac roots. Persian berries give a fast dull yellow. Turmeric is from the root of a plant growing abundantly in East India and China and it gives a bright orange color. Orange yellow is also obtained from henna and by combining madder and turmeric. A light yellow is obtained from larkspur; a greenish yellow from a fungus of the mulberry, and, of late years, a buff colored yellow has been obtained from quercitron bark.

Black.—Black seems to be the only color which the rug makers of older days were unable to produce from vegetable or animal sources. The principal black used was that made from iron filings with vinegar and pomegranate rind, but it destroyed the fibres of the wool. For this reason very little black was used in the antique pieces excepting where the fleece of black sheep could be obtained. Nowadays logwood, which grows in Central America, is the essential basis of all blacks in wool, although other colors are frequently used with it to modify or intensify the shade.

Purple.—From very early times the Phoenicians were renowned for a purple which they obtained from a shellfish found in the Ægean Sea, but the secret of making it has long since become a lost art. A great many shades of purple, heliotrope and lavender are obtained from the different red dyes in combination with indigo and the dye woods as well as from the bodies of marine insects and mollusks.

Gray.—Gray is secured from Smyrna gall-nuts with copperas.

Salmon.—Salmon is obtained by mixing madder with valonia.

Violet.—Violet is frequently made from milk, sour grape juice, madder and water.