386

DYEING AND CALICO PRINTING.

of carbonate, borate or phosphate of soda. For this purpose safflower is firstfreed, as far as possible, from its yellow colouring matter, by being wellwashed with acidulated water, and is next treated with a dilute cold solutionof carbonate of soda (ordinary washing soda, 13 per cent); the mixture iswell squeezed, and to the clear bright yellow liquid thus obtained an acid isadded, whereby the carthamic acid, along with many impurities, is precipitated.It would be almost impossible to free the carthamic acid from these foreignsubstances, but this result is very readily brought about by immersing into thealkaline solution, previous to the addition of an acid, a quantity of cotton-wool. This material attradts, by a special adtion, the carthamic acid at themoment it is set free by the addition of an acid ; and the cotton-wool mayfirst be washed in a weak acid, and next in water, and, lastly, again with aweak alkaline liquid, which re-dissolves the carthamin. After removal of thecotton-wool, plenty of which should be used, it is re-precipitated by an acid,very dilute citric or tartaric being the best. It falls down in the state of abeautifully rose-red fiocculent matter, which may be colledted on a filter,washed, and dried. In order to obtain a still purer material, the fiocculent drysubstance should be dissolved in alcohol, and this solution, after having beenstrongly concentrated, is poured into a large bulk of water, and the precipitatethus formed is again colledted on a filter and dried. Care should be taken toavoid the use of too strong alkaline solutions,, nor should they be exposed toair for any length of time, since this completely alters the colouring matter.

Carthamin in a pasty state, as obtained by the processes just described, ismet with in commerce suspended in water for diredt use. The paste is driedupon suitable vessels—porcelain saucers, plates of porcelain, or even uponpolished cardboard. The colouring matter, when dry,, has a pecular cantha-rides-like gloss and brilliancy, not unlike fuchsine ; the powder is beautifullyred, and is used also when mixed with French chalk and rubbed down withwater and again dried, as a rouge.

Carthamin is insoluble in ether, almost so in water, but soluble in alcohol,to which it imparts a cherry-red. This alcoholic tindture dyes silk imme-diately, no mordant being required. Carthamin is altered by boiling withwater and with alcohol; it is soluble in concentrated sulphuric acid, forminga red liquid, but water does not precipitate it from this solution. Nitric acidand dilute sulphuric acid dissolve the carthamin, producing yellow liquids.Carthamin is an acid, the alkaline carthamates being yellow or orange-yellow,and yielding when in solution, on the addition of an acid, precipitates of car-thamic acid.

Carthamate of ammonia yields, with bichloride of tin, a yellowish-brownprecipitate ; with perchloride of iron, a brownish-red ; and with bichloride ofmercury, a red precipitate.

According to Dr. Schlieper, the composition of the yellow matter of saf-flower is CjsHzoOio, while the formula of carthamic acid is, according to him,

C14H16O14.

Before the discovery of the aniline dyes, safflower was very frequently usedto dye silk, wool, and even cotton fabrics. In order to apply it to cotton theware is first placed in canvas bags, and thoroughly washed with slightlyacidulated water, so as to eliminate all the yellow colouring matter as muchas possible. It is next treated with carbonate of soda (15 per cent of the