The bark, very dark externally, is an excellent tanning substance; the inner layers form the quercitron of commerce, used by dyers for communicating to fabrics various tints of yellow, and, with iron salts, yielding a series of brown and drab hues; the colouring property depends on a crystalline principle called quercitrin, of which it should contain about 8%.
Of the vegetable oils, in addition to cotton-seed and coco-nut, olive oil is the basis of soaps for calico printers and silk dyers; castor oil yields transparent soaps (under suitable treatment), whilst crude palm oil, with bone fat, is employed for making brown soap, and after bleaching it yields ordinary pale or mottled.
The oxymuriate of tin used by dyers is SnCl4.5H20.
Gall nuts, gathered on the neighbouring Kurdish mountain slopes, are mostly exported, but are also made use of by native dyers; and hides, wax, cotton and gum are sold.
Up to 1857 the utmost the dyer could add was " weight for weight," but an accidental discovery that year put dyers into the way of using tin salts in weighting with the result that they were enabled to add 40 oz.
The use of tin salts, especially stannic chloride, SnC1 4, enables dyers to weight all colours the same as black.
It is much resorted to for weighting coloured silks by dyers on the continent, and, though a very clumsy method, no substitute has been found so cheap and easy of application.
Many dyers' furnaces, a little silver refinery, and perhaps a bakery have also been noticed.
Since, however, the value of all good furs has advanced, dyers and manufacturers have made very successful efforts with this fur.
The Paris dyers do excellent work in this direction, but the colour is not so durable, probably owing to a less pure water.
Boldon Book, dated 1183, contains the first mention of Darlington as a borough, rated at 5, while half a mark was due from the dyers of cloth.
Until the 19th century it was governed by a bailiff appointed by the bishop. The mention of dyers in the Boldon Book and Hatfield's Survey probably indicates the existence of woollen manufacture.
Drapers, dyers and glovers in the, 6th century.
Among the vegetable products not yet mentioned the most important are the mulberry, grown in almost all provinces, but principally in those bordering on the Mediterranean, and above all in Valencia, the chief seat of the Spanish silk production and manufacture; tobacco, which is also imported, hemp and flax, grown chiefly in Galicia and other northern provinces; among dye-plants, madder, saffron, woad (Isatis tinctoria), and wild woad or dyers weed (Reseda luteola); ground-nuts (Arachis hypogaea), grown for their oil, for the preparation of which the nuts are exported in considerable quantity to France; liquorice, cummin, colocynth, &c. Esparto, chiefly from the arid lands of the south-east, is largely exported to Great Britain.
Up to 1840 the mill hands, with the exception of English dyers and calico printers, were New England girls.
In later documents mention is made of eighteen gilds of work-people, whose names are nowhere given, but they probably included workers in wood, workers in metal, workers in stone, weavers, leather-workers, potters, ivory-workers, dyers, fisher-folk, butchers, hunters, cooks, barbers, flowersellers, sailors, basket-makers and painters.
Dyers' shops, a tannery and a shop where colours were ground and manufactured - an important business where almost all the rooms of every house were painted--are of special interest, as is also the house of a surgeon, where numerous surgical instruments were found, some of them of a very ingenious and elaborate description, but all made of bronze.