LOGWOOD.

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which solution are added 3-5 kilos, of hydrochloric acid. The goods areplaced in this mixture, and the temperature raised to boiling, when the fibretakes a deep indigo-blue, which passes into bluish-black after washing inwater. The two last-mentioned dyeing processes resemble those in use forthe fixation of catechu colours: there is, indeed, a similarity of behaviour, asfar as the dyeing process is concerned, between hematoxylin and catechin.Uniform greys are obtained by means of logwood, by first mordanting thefabric by working in a weak solution of pyrolignite of iron. After oxidationand cleansing, the goods are dyed by being winced in a dye-beck containingthe logwood reduced to powder, or in the shape of shavings, and by elevatingthe temperature gradually to boiling. The decodlions and extracts of logwoodserve for the preparation of a very large number of steam and applicationcolours, of the making up of which we quote the following as representingthe ingredients:—

Steam-Black on Cotton. —Extradl of logwood, at 6° Baume (sp. gr. 1*044),5 kilos.; acetic acid, 1*25 kilos.; pyrolignite of alumina, at io° Baume (sp. gr.1*075), 1*25 kilos.; pyrolignite of iron, at 14 0 B. (sp. gr. 1*106), 1*25 kilos. ;white starch, 750 grms. This mixture is to be boiled for an hour, and keptstirred until cold. It is next printed on, dried, and steamed.

Steam-Black for Roller-Printing .—Extradl of logwood, at 17 0 B. (sp. gr.1*134), 5*5 litres ; pyroligneous acid, at 2 0 B. (sp. gr. 1*014), 2 litres ; pyroligniteof iron, at 12 0 B. (sp. gr. 1*091), 6 litres ; starch, 2*125 kilos.; gum substitute,2*125 kilos.; oil, 0*12 litre.

Steam- and Application-Black for Roller-Printing. —Water, 2*5 litres ; pyro-lignite of iron, at 14 0 B. (sp.gr. rio6), n litres; pyroligneous acid, at 2 0(sp. gr. 1*007), 4*5 litres; extract of logwood, at 20° B. (sp. gr. 1*162),6*75 litres ; white starch, 3*508 kilos.; gum substitute, 4 kilos.; Gallipoli oil,1*5 litres.

Bluish Application-Black. —Logwood decodtion, at 4 0 B. (sp. gr. i*02g),20 litres ; white starch, from 3 to 4 kilos. This mixture is boiled, and after ithas become cool there are added to it, of chlorate of potassa, 40 grms., and ofrose-red liquor (mordant for), 2 kilos. The black produced by this mixture isvery rapidly developed by exposing the fabrics in heated ageing-rooms.

Extradl of logwood is also used mixed with the extradls of the red woodsand of quercitron, for the production of brown and pomegranate application-colours upon cotton, while the logwood extradl by itself is applied for steam-ed application-lilacs. The following may serve as instances of the makingU P these colours :—

Deep Lilac Colour for Block-Printing. —Water, 48 litres ; extradl of logwood,at io° B. (sp. gr. 1*075), 8 litres ; gum, 17 kilos. ; alum, 3*8 kilos.; nitrate ofcopper solution, at 50° B. (sp. gr. 1*532), 250 grms.

Steam-Lilac for Roller-Printing. —Logwood extradl, at 8° B. (sp. gr. 1*060),8 litres; acetate of alumina, at 15 0 B. (sp. gr. 1*116), 1*5 litres. This acetateis made up of—Water, 5 litres ; alum, 2*5 kilos.; acetate of lead, i*8 kilos.;oxalic acid, 240 grms.; gum, 1*25 kilos.

Application-Lilac. —Logwood decodtion, at 5 0 Baume (sp. gr. 1*036), 10 litres ;water, 4 litres ; gum, 8 kilos.; sal-ammoniac, 750 grms. ; salt for rose-red,*

Has been described above under Brazil Wood, and is prepared as follows:—12 kilos, nitricac »d, at 30° B. (sp. gr. 1*261); water, 3*25 kilos.; sal-ammoniac, 1*23 kilos.; bichloride of tin,1 5 kilos.; pure metallic tin, 1*5 kirns.