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DYEING AND CALICO PRINTING.

6. Pectose .—According to Schiitzenberger, madder contains pedlose, which

he infers from the fadt that on adding an aqueous solution of madderto solutions of pedtin, the latter were speedily gelatinised.

7. Chlorogenin (Schunck), called rubichloric acid by Rochleder.

This substance is one of the immediate principles of madder and of a fewother plants. When boiled with weak mineral acids it is decomposed, yieldinga sap-green insoluble matter.

8. Alkaline Tartrates, Malntes, and Citrates, according to Rochleder are

found in the cold aqueous extradt, though the Levant madders wereasserted to contain citrates only. Dr. Schunck has never met witheither tartaric, citric, or malic acid in madder, but with abundanceof oxalic in their stead. He very justly remarks that in the olderanalyses of vegetable matters non-crystallisable acid syrups werecommonly set down as “malic acid.”

g. We find, further, nondescript extradlive matters with colouringglucosides, of which we shall treat below.

10. Alkaline sulphates, phosphates, and chlorides.

b. Substances Soluble in Boiling Water and in Alcohol.—

These comprise chiefly the colouring matters and resins, of which we shallspeak subsequently.

The immediate principles insoluble in water and alcohol comprise 32 to 40per cent of woody fibre, dedudtion having been made for the mineral con-stituents. This insoluble portion is made up of cellulose, free pedticacid, pedtose, pedtate, oxalate, carbonate, and phosphate of lime ; phosphateof magnesia with silica, alumina, and oxide of iron. The study of the ash,both as to its quality and quantity, is of great importance, since it not onlyaffords the means of detedting a certain class of adulterations, but bears uponthe results obtained in dyeing with different kinds of madder. The ash, whichis not easily obtained quite free from traces of organic matter, contains themineral salts naturally present in the plant, and those formed by the decom-position of the salts of organic acids. Among the latter occur, therefore,carbonates of soda, potash, and lime. The composition of the ash varies,as might be expedted, with the composition of the soil in which the madderis grown. The percentage differs also greatly. Chevreul found in 100 partsof Levant madder* g-8 of ash, and in that of Alsace g ; 5 to 12 and 13.According to Schlumberger, Avignon madder yields on an average 8'o8per cent of ash, and that of Alsace 7’20. Persoz (senior) found thefollowing percentages, noting expressly that he employed pure nitrateof ammonia in order to burn off the last traces of carbon:—Alizarifrom Avignon, 8’i to 8-03 ; racine from Alsace, 6-3 to 6-05 ; pure palud madderfrom Vaucluse, g-6 to 1072 ; rosee from the same distridt, 8-4 to 8-85. Alsacemadder, 7 - g to 7'02. Girardin states that several experiments made by himwith pure madder yielded only 5 per cent of ash. Notwithstanding thisauthor’s great authority, it is undeniable that his statement only refers to the

* The question arises whether this has been madder, or racine. No roots are ground inthe Levant or Barbary, and the root only comes into the market as “alizari” or “racine.”“ Marena ” is only occasionally brought to Europe.