ANILINE BLUES.

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affinity for cotton than most aniline colours. In some cases, where conve-nience requires highly concentrated solutions, these colours also are dissolvedin alcohol, wood-spirit, or glycerine.

In dyeing the same general principles are observed as in case of magenta.In Hofmann’s violets for wool and worsted the goods should be entered at120 0 F., and the temperature be very gradually raised up to 212 0 F. Greatcare should be taken not to add an excess of colour, which is certain toproduce flushing or bronzing. The annexed specimen is dyed with Hofmann’sB., as prepared by Messrs. Brooke, Simpson, and Spiller. Cotton andmixed goods may be dyed as directed for magentas.

The following method of fixing the aniline colours upon cotton is due toLloyd and Dale:—To 4J litres of gum-water we add 240 to 300 grms. of puredry tannin, and the colouring matter more or less according to the shaderequired. After printing and steaming at a pressure of about 50 to 75 grms.to the square centimetre, the pieces are then passed through a bath oftartrate of antimony or bitartrate of potash and antimony (tartar-emetic),containing 13^ grms. of this salt to the litre, and heated to 45 0 to 85° C. Thegoods are then rinsed and dried. A variation of the method is to print on thecalico a thickened solution of tannin (133 grms. of tannin to a litre of gum-water for full, and 20 to 27 grms. for light shades). After printing, the piecesare steamed for an hour, and passed into the antimonial bath. They are nextwell washed and dyed in the colour-bath, which is slightly acidulated, andheated slowly to the boiling-point, at which it is maintained for twentyminutes. If after washing the white grounds are still faintly stained, they arebleached by being passed through a weak solution of chloride of lime, andafterwards through soap-lyes.

The addition of acids renders the tone more blue, but at the same time itdeadens the colour and impairs its affinity for the fibre, especially in case ofcotton.

ANILINE BLUES.

Paris Blue (Persoz, De Luynes, and Co.), Lyons Blue (Girard and De Laire),Mulhouse Blue (Gros-Renaud), Azurine (Calvert and Lowe), Azuline ,Rosaniline Blue, Blcuine , Oxyphenylanilide , DioxyphcnylaniUde, NightBlue , Methylaniline Blue, Triphenylic Rosaniline, Toluidine Blue , Roso-toluidine Blue, Opal Blue, Regina Blue, Nicholson Blue , Guernsey Blue.

Lauth observed on December 24th. i860,* that when magenta, especiallyazaleine, is heated with a reducing agent, such as protochloride of tin, apurple and even a blue were obtained. In continuing these researches heobserved that a blue matter could be easily obtained by heating azaleine withvarious organic compounds, such as aldehyde, several of the hydrurets ofbenzyl, acetyl, and many natural essences. This blue colour cannot resistthe action of acids and of light, and is therefore practically useless. Theaction of aldehyde and the composition of the blue itself have been investi-gated by M. Willm, and are exhibited by the following formula :—

z JCgGHaoN^ + S^H^+SHO^ s^H^NO^ +jC^-Igi NH^O^ .

Azaleine. Aldehyde. Blue, or Acetate of Ammonia,

Oxyphenylanilide.

* See vol. xxxi. of the “ Bulletin de la Societe Industrielle de Mulhouse.”

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