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DYEING AND CALICO PRINTING.

In dyeing with coralline the bath is prepared as follows:—The colour isdissolved in alcohol, a little soda added, and the alkaline liquid poured intoa large quantity of water. By a slight addition of tartaric acid the colour isset at liberty without being precipitated. In this bath shades are obtainedintermediate between those of cochineal and magenta. Cotton requires to bepreviously mordanted with tin-salt and sumac or gall-nuts. The goods arethen entered into the colour-bath, which should be lukewarm, and are workedfor ninety minutes. For a full shade 500 grammes of coralline are consumedper piece. The shade obtained resists steaming and washing, but is quicklyaffeCted by soap, alkalies, and light. By a momentary exposure to ammoniait may be modified to a carmine, but this colour is exceedingly unstable.

Coralline thrown down from its solution in acetic acid by the addition ofwater, and dried at a temperature below its point of fusion, is a fine redpowder, which can be printed as a pigment colour by means of albumen.

Yellow coralline is a modification of the above colour; the exaCt mode ofthe preparation has not been made public. It yields upon wool very fine orangeshades, which are thus obtained :—2J kilos, of yellow coralline are dissolvedin 10 litres of caustic soda at io° B. at the temperature of 6o° C. It ispoured into 100 litres of water, heated again, and when completely dissolved1 litre of bichloride of tin at 55 0 B. is added, previously diluted with 5 litresof water. On filtering we obtain 20 litres of a bright orange lake. 10 litresof this without previous washing are mixed with 2 kilos, of powdered gumand 350 grms. of oxalic acid. The mass is heated till the gum and acid aredissolved, strained, and printed on wool. After twelve hours it is steamedfor forty minutes.

The accompanying specimen of coralline yellow is produced by thefollowing process. The colour is dissolved in dilute ammonia to the strengthof 32 0 Tw. One measure of this solution is mixed with 4 measures of starchpaste, containing 14 lbs. per gallon, printed, dried, and steamed for one hour.

The following formula gives a good red upon delaines, resembling Turkeyred:—

Red coralline .80 grms.

Dissolve in a hot mixture of litre of glycerine and £ litre of water. In aseparate vessel 140 grms. of calcined magnesia are stirred up in £ litre ofwater. The whole is then mixed together with | litre of solution of gum,containing 500 grms. per litre.

Another derivative of phenol is picric acid, otherwise known as trinitratedphenic acid, carbazotic acid, nitrophenisic acid, nitropicric acid, &c. It isproduced by the action of nitric acid upon indigo, silk, aloes, the resin ofXanthorrhea hastilis, and especially phenol. The present mode of manu-facture is to pass, in small quantities at a time, a stream of nitric acid intopure carbolic acid, or into a previously formed mixture of carbolic and sulphuricacids, or better still by attacking the crystalline sulpho-carbolate of soda withnitric acid. Picric acid forms small brilliant yellow crystals, of an intenselybitter taste, and moderately soluble in water. It dissolves in sulphuric andnitric acids without change, and is re-precipitated on the addition of water.Its tinctorial power is enormous, and its affinity for animal fibres is very great,but upon vegetable fibres and tissues it can only be fixed by the aid ofanimal mordants. With bases picric acid forms a series of well-defined salts,