Dingler has endeavoured to separate the colouring matter of the different sorts of Brazil wood, so as to obtain the same tint from the coarser as from the best Pernambuco. His process consists in treating the wood with hot water or steam, in concentrating the decoction so as to obtain 14 or 15 pounds of it from 4 pounds of wood, allowing it to cool, and pouring into it two pounds of skim milk; agitating, then boiling for a few minutes, and filtering. The dun colouring matters are precipitated by the coagulation of the caseous substance. For dyeing, the decoctions must be diluted with water; for printing they must be concentrated, so that 4 pounds of wood shall furnish only 5 or 6 pounds of decoction, and the liquor may be thickened in the ordinary way. These decoctions may be employed immediately, as by this treatment they have acquired the same property as they otherwise could get only by being long kept. A slight fermentation is said to improve the colour of these decoctions; some ground wood is put into the decoction to favour this process.
As gelatine produces no precipitate with these decoctions, they consequently contain no tannin. Gall-nuts, however, sumach, the bark of birch or alder, render the colour of Brazil wood more durable, upon alumed linen and cotton goods, but the shade is a little darker.
In dyeing wool with Pernambuco, the temperature of the bath should never be above 150° Fahr., since higher heats impair the colour.
According to Dingler and Kurrer, bright and fast scarlet reds may be obtained upon wool, by preparing a decoction of 50 pounds of Brazil wood in three successive boils, and setting the decoction aside for 3 or 4 weeks in a cool place; 100 pounds of the wool are then alumed in a bath of 22 pounds of alum and 11 pounds of tartar, and afterwards rinsed in cold water. Meanwhile we fill two-thirds with water, a copper containing 30 pails, and heated to the temperature of 150° or 160° F. We pour in 3 pailfuls of the decoction, heat to the same point again, and introduce 30 pounds of wool, which does not take a scarlet, but rather a crimson tint. This being removed, 2 pails of decoction are put in, and 30 pounds of wool which becomes scarlet, but not so fine as at the third dip. If the dyer strengthens the colour a little at the first dip, a little more at the second, and adds at the third and fourth the quantity of decoction merely necessary, he will obtain an uniform scarlet tint. With 50 pounds of Pernambuco 1000 pounds of wool may be dyed scarlet in this way, and with the deposits another 100 may be dyed of a tile colour. An addition of weld renders the colour faster but less brilliant.
Karkutsch says the dye may be improved by adding some ox-gall to the bath.
In dyeing cotton the tannin and gallic acid are two necessary mordants, and the colour is particularly bright and durable, when the cloth has been prepared with the oily process of Turkey red.
It is said that stale urine heightens the colour of the Brazil dye when the ground wood is moistened with it.
The quantity of Brazil or Nicaragua wood imported into the United Kingdom in 1835, was 6,242 tons, whereof 1,811 were exported; of Brazilietto 230 tons. The duty upon the first article is 5s. per ton.
BREAD (Pain, Fr.; Brod, Germ.) is the spongy mass produced by baking the leavened or fermented dough of wheat or rye flour, at a proper heat. It is the principal food of highly civilized nations. The skilful preparation of this indispensable article constitutes the art of the Baker. Dough baked without being fermented constitutes cakes or biscuits; but not bread strictly speaking.
Pliny informs us, that barley was the only species of corn at first used for food; and even after the method of reducing it to flour had been discovered, it was long before mankind learned the art of converting it into cakes.