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DYEING AND CALICO PRINTING.

carbon. Alkalies, and soluble alkaline borates and phosphates, dissolvemorin, giving yellow solutions, which are precipitated by acids. The alco-holic solution is coloured a deep olive-green by perchloride of iron. Morinloses its water of crystallisation with great difficulty.

According to Dr. Hlasiwetz the composition of morin, dried at 200°, isC I2 H 8 0 3 , while the air-dried substance is represented by C i2 H 80 5 iJH 2 0 .Morin readily combines with potassa, soda, lime, baryta, oxides of zincand lead, all these compounds being yellow. It absorbs ammonia, evenso as to increase its weight by 12-7 per cent, causing the formation of abody C I 2 H I 0 O6+2NH 3 — H 2 0 . It also combines with bromine, and is readilyconverted into phloroglucin under the influence of nascent hydrogen or byfusion with alkalies.

It appears from the investigations made by Hlasiwetz that there exists greatanalogy between morin and quercetin, as may be inferred from the followingbrief quotations from the lengthy memoir of the author on this subjedt:—Both these substances yield, when treated with sodium amalgam while in anacidulated alcoholic solution, a red body; treated with the same amalgam inan alkaline solution, phloroglucin is formed ; both unite with potassa andsoda, as well as with zinc ; both are converted by fusing caustic potassa intophloroglucin, and both withstand a high temperature and lose their water ofcrystallisation with difficulty.

Fustic is employed for the preparation of decodtions and more or less con-centrated extradts which are used in dyeing, while it also serves for themanufacture of lakes destined for paints and for calico-printing. The shadesof colours produced are nearly the same as those from quercitron, and areequally stable.

Weld.

(French, Gaude ; German, Wau ; Dutch, Wouw.)

This substance is the dried herbaceous plant known botanically as Resedaluteola. It is cultivated on the Continent of Europe, but in this country hasfallen into disuse ; it is sown in June, and gathered the next year: the plant,which reaches about 1*3 metres in height, is brown, like grass dried in theshade, and sold in sheaves, like straw. It consists of a main stem and severalsmaller branches, of a yellow or greenish-yellow colour, according to the caretaken in drying.

Weld is cultivated in several parts of France, in Germany, and the Austro-Hungarian empire. The colouring matter is dispersed through the entireplant, but is most accumulated towards the upper extremity and in the seeds.The decodtions of this material have a greenish-yellow colour, a sweetish-bitter taste, and a very disagreeable odour. Alkalies turn this decodiion agolden-yellow; acids deepen the yellow hue; with sulphate of iron an olive-green is produced, while most of the metallic salts give yellow precipitates.Gelatin causes only an insignificant precipitate in the decodiion.

Though the use of weld in this country has almost entirely ceased, mainlyowing to the fadt that farmers do not cultivate it here as they used to do, andon account also of the bulk of the material, we must not omit to enter intosome details of the chemical history of this dye-ware, which is the oldestEuropean yellow dye known, and was used even by the Gauls and othernations dwelling north of the Alps in the time of Julius Ctesar. The