This property is usually obtained by mixing soft and hard soaps, or, more rarely, by adding gum tragacanth to a hard soap. In the textile trades the wool scourer employs a neutral olive-oil soap, or, on account of its cheapness, a neutral curd or curd mottled brand; the cotton cleanser, on the other hand, uses an alkaline soap, but for cleaning printed cottons a neutral olive-oil curd soap is used, for, in this case, free alkali and resin are objectionable; olive-oil soap, free from caustic alkali, but often with sodium carbonate, is also used in cleansing silk fibres, although hard soaps free from resin are frequently employed for their cheapness.
The majority of plant specimens are most suitably fastened on paper by a mixture of equal parts of gum tragacanth and gum arabic made into a thick paste with water.
For attaching it to the paper a strong mucilage of gum tragacanth, containing an eighth of its weight of spirit of wine, answers best.
The most important vegetable productions are - cereals, cotton, gum tragacanth, liquorice, olive oil, opium, rice, saffron, salep, tobacco and yellow berries.
The exports are: - Cereals, cotton, cotton seed, dried fruits, drugs, fruit, gall nuts, gum tragacanth, liquorice root, maize, nuts, olive oil, opium, rice, sesame, sponges, storax, timber, tobacco, valonia, walnut wood, wine, yellow berries, carpets, cotton yarn, cocoons, hides, leather, mohair, silk, silk stuffs, rugs, wax, wool, leeches, live stock, minerals, &c. The imports are: - Coffee, cotton cloths, cotton goods, crockery, drysalteries, fezzes, glass-ware, haberdashery, hardware, henna, ironware, jute, linen goods, manufactured goods, matches, petroleum, salt, sugar, woollen goods, yarns, &c.
Manna and gum tragacanth are also collected.
Among the valuable vegetable products forming articles of export are various gums and dyes, the most important being gum tragacanth, which exudes from the astragalus plant in the hilly region from Kurdistan in the north-west to Kermn in the south-east.
Of dye-yielding shrubs and plants camwood and indigo may be mentioned; of those whence gum is obtained the copal, acacia and African tragacanth (Sterculia tragacantha).
Ferri sulphas exsiccatus, which has two subpreparations: (a) Pilula ferri, " Blaud's pill " (exsiccated ferrous sulphate 150, exsiccated sodium carbonate 95, gum acacia 50, tragacanth 15, glycerin 10, syrup 150, water 20, each to contain about I grain of ferrous carbonate); (b) Pilula aloes et ferri (Barbadoes aloes 2, exsiccated ferrous sulphate I, compound powder of cinnamon 3, syrup of glucose 3).
Silk and cocoons Opium Gum tragacanth Wool .
Gum tragacanth, familiarly called gum dragon, exudes from the stem, the lower part especially, of the various species of Astragalus, especially A.
In colour gum tragacanth is of a dull white; it occurs in horny, flexible and tough, thin, twisted flakes, translucent, and with peculiar wavy lines on the surface.
Gum tragacanth is used in calico-printing as a thickener of colours and mordants; in medicine as a demulcent and vehicle for insoluble powders, and as an excipient in pills; and feltsetting and mending beetles and other insect specimens.
Gum kuteera resembles in appearance gum tragacanth, for which the attempt has occasionally been made to substitute it.
Under the name of Caramania gum it is mixed with inferior kinds of gum tragacanth before exportation.