DYEING. 



229 



Adjective 



Colouring 



Matters. 



inferior sort of carmine is prepared, and also a liquid 

 lake for miniature painting. Alum and tartar produce 



.__ ^. a little brownish red precipitate. Sulphate of iron 

 ^" v """ ' causes the tincture to assume a black colour, inclining 

 to violet. Sulphate of copper produces a very copious 

 precipitate of a still darker colour. A solution of ace- 

 tate of lead causes an abundant precipitate of a pretty 

 fine deep red. A solution of nitro-muriate of tin gives 

 a very copious precipitate of a fine rose colour : the li- 

 quor remaining transparent, and perfectly colourless. 



132. It has been remarked, that the decoction of 

 Brazil wood is less proper for dyeing when fresh, than 

 when it has been kept for some time after being pre- 

 pared ; and it is even said, that it answers the purpose 

 best after it has undergone a certain degree of fermen- 

 tation. Hellot recommends the hardest water that can 

 be procured for making the decoction : such water 

 deepens the colour, by means of the earthy salts which 

 it contains. Having boiled the wood reduced into 

 chips for three hours, the liquor is poured into a cask ; 

 fresh water is added to the Brazil, it is boiled three 

 flours longer, and the liquor is added to the former. 

 When the wood is used in a dye-bath, or flat, it is pro- 

 per to inclose it, and indeed all colouring woods, in a 

 thin linen bag. 



(.'.Tsalpinia 133. The colouring matter of the Caesalpinia sappan 



Mppaa. ig go nearly allied in its properties and effects to that 

 of Brazil wood, that any particular account of it is un- 

 necessary. The principal difference between these 

 woods, is in regard to the quantity of colouring matter 

 wlu'ch they afford. That of the best sappan wood, ac- 

 cording to the experiments of Dr Bancroft, does not 

 amount to one-half of that which may be obtained 

 from an equal weight of Brazil wood, while, at the 

 same time, it is less bright. 



Tfwhwood. 13-t. Peachwood is almost as heavy and deeply co- 

 loured an the true Brazil wood, but it does not afford 

 one-third the quantity of colouring matter, which is 

 both less beautiful and less durable. Some of the va- 

 rieties of this wood are still more inferior in quality, 

 and sell proportionably cheap. The best is produced 

 near the Rio de la Hacha, eastward of St Martha, and 

 gives nearly half as much colouring matter as Brazil 

 wood. The Dutch have given it the name of Stock- 

 vish-hout ( stock-fish- wood). Camwood, the wood of a 

 tree imported from Africa by the Portuguese, afford* a 

 red colouring matter similar to that of peachwood, and 

 may be treated in the same manner as a dye. Jamaica 

 brazileito, and Bahama brazilftto, probably belong to 

 the same species, though they are usually classed as 

 different They afford the least valuable of the dyeing 

 woods, and are only employed for producing inferior 

 and fugitive colours. 



135. Barmood is obtained from Africa, principally 

 from Angola, and is used as a dye. With the alumi- 

 noii^ mordant, it affords yellowish-brown reds to wool 

 and cotton, though they are rather fugitive on the lat- 

 ter. The colour extracted from barwood may be sad- 

 dened by employing solutions of iron along with it, 

 either alone or conjointly with alum. The dark red, 

 which is commonly seen upon the British imitations of 

 East India silk handkerchiefs, is generally given by 

 barwood and sulphate of iron. 



136. Red saunders, the wood of a tree which is brought 

 from Coromandel, i-i also used as a dye. Its colouring 

 matter is imperfectly soluble in water, even with the 

 awutance of potash or soda. Dr Bancroft found, that 

 a diluted sulphuric acid acted very efficaciously in ex- 

 tracting the colour of this wood. Vogler says, tliat, by 



Adjective 

 Colourinj 



M.tttere. 



nwood. 



Red sun- 

 4m. 



extracting the colour of red saunders by alcohol, he 

 communicated to wool a colour almost equal to scarlet. 

 A very bright and lasting orange may be given to 

 broad-cloth, prepared, as usual, with alum and tartar, 

 by employing equal portions of ground sumach and 

 rasped saunders. 



137. The wood of the Hfematoxylon Citmpec/iianum Logwood, 

 affords a colouring matter, which is used very exten- 

 sively in dyeing. In commerce, it is known by the 



name of logwood, and also of India or Campeachy 

 wood. Logwood is so heavy as to sink in water ; it 

 possesses great hardness, and, by the compactness of 

 its grain, takes a fine polish. Its prevailing colour is 

 red, tinged with shades of orange, yellow, and brownish 

 black, and is extracted in the same manner as that of 

 Brazil-wood. Six quarts of distilled boiling water are 

 capable of extracting almost all the colouring matter 

 of one pound of logwood properly chipped. The de- 

 coction is of a yellow colour, and has a sweetish taste. 

 If the decoction be made with common water, it ex- 

 hibits a full red, or dark blood colour, probably by the 

 action of the, calcareous earth which common water 

 usually contains in combination with it; but by adding 

 to it sulphuric, nitric, or muriatic acid, the yellow is 

 restored. 



138. When logwood is of a good quality, it yields The deeoc- 

 from one-fifteen8i to one-twentieth of its weight of tion loses its 

 pure colouring matter, soluble in water and in alcohol, 



if the decoction after being obtained has been speedily 

 evaporated to dryness ; but if an interval of several 

 weeks has been allowed to intervene, or if the evapo- 

 ration has been conducted slowly, and the decoction 

 has been exposed to the sun and air, the colouring mat- 

 ter will absorb a large quantity of oxygen from the 

 atmosphere, and become nearly insoluble in water, 

 while the colours dyed from it will be more fugitive 

 than those produced by a decoction recently prepared. 

 In this respect it differs greatly from Brazil wood. 



139. Chips of logwood being boiled in water acidulat- HOW afftct- 

 ed with sulphuric acid, afford a brownish yellow decoc- ed by dif- 

 tion, which communicates to wool a strong yellowish ferent a- 

 bright snuff colour, of considerable durability. Nitric B cnt8g 

 acid being mixed with a decoction of logwood, produces a 



fine bright yellow, which becomes a yellowish brown 

 by boiling, and imparts the same colour to wool. Cloth 

 boiled with a decoction of logwood, slightly acidulated 

 by muriatic acid, takes a brownish yellow colour. If 

 a sufficient quantity of alum be added to a decoction of 

 logwood, the colouring matter is all precipitated in 

 combination with the alumnfe, of a purple or reddish 

 violet colour. A sulphate of iron occasions a copious 

 bluish black precipitate. All the solutions of tin pro- 

 duce purple or violet colours, and a complete precipita- 

 tion of the colouring matter. Sulphate of copper gives 

 a purplish blue colour ; sulphate of pure zinc, a dark 

 purple ; muriate of mercury, an orange red ; muriate 

 of antimony, a beautiful crimson ; acetate of lead, a 

 black precipitate, with a slight tinge of red ; muriate 

 of barytes, a reddish purple ; muriate of magnesia, a 

 yellow ; sulphate of lime, a purple ; arseniate of pot- 

 ash, a deep yellow. 



1 4-0. Tile best and most permanent of the purple or 

 violet colours obtained from logwood, are produced 

 by mordants, principally composed of the solutions of 

 tin. In another part of this article, we shall describe 

 the process employed for dyeing in this way upon wool, 

 a colour which was very fashionable in France, upward* 

 of thirty years ago, under the name of Prune de Mon- 

 sieur. Wool dyed with logwood, and either sulphate 

 1 



