34 °
DYEING AND CALICO PRINTING.
high specific gravity, viz. 1*014, very dry and compact, of a blackish-browncolour externally, while within it is red. The fibres of this wood occuralternately in layers running in opposite directions ; as a consequence thereof,when an attempt is made to plane it, it will exhibit alternately a polished anda rough torn-up surface. For dyeing purposes the old wood is the best,because it is richer in colouring matter.
Santal wood is met with in commerce in the state of a powder specificallylighter than water, with a smell like that of orris-root; its taste is somewhataromatic. This substance contains pigment, gummy and astringent matters,chloride of calcium, sulphate of lime, chloride of potassium, organic potassasalts, phosphate of magnesia, alumina, oxide of iron, and silicic acid. Thecolouring matter of santal wood is insoluble in cold water, very slightly solublein boiling water, readily soluble in alcohol, ether, acetic acid, and causticalkalies, and precipitable from its solution therein by an acid.
The chemistry of this produdt is by no means quite complete. Pelletierwas the first who discovered and isolated santalin as a red resin, the solubilityand properties of which are those above described. Meier prepares santalinby treating the wood with ether; the concentrated solution yields the sub-stance in a crystalline yet impure state. These crystals are first washed withwater, and next re-dissolved in alcohol; the alcoholic solution is precipitatedby acetate of lead, and the ensuing precipitate washed with boiling alcohol,and next decomposed by means of sulphuric acid in the presence of alcohol.After removing the sulphate of lead, the previously concentrated alcoholicsolution deposits santalin, in the shape of small crystals, of a beautiful redcolour, fusing at 104°. Dr. Dussauce’s plan of preparing santalin is by pre-cipitating the alcoholic extract of the wood by means of hydrated oxide oflead. After washing, the precipitate is dissolved in acetic acid, and to thissolution a large quantity of cold water is added, which indeed precipitates thecolouring matter, but in a rather impure state, since the dye thus obtaineddoes not yield good results.
Santal Wood contains on an average about 16 per cent of santalic acid.According to the researches of Weyermann and Hseffely the composition ofsantalin is Cx 5 H I4 0 5 . This result was controlled by the analysis of a barytasalt of santalin, obtained in the shape of a violet crystalline precipitateby adding chloride of barium to an ammoniacal solution of santalin : theformula of this compound was found to be C3 0 H 2 6BaO I0 . Dr. Bolley considersthat santal wood contains two different colouring matters, one of which isricher in oxygen but poorer in hydrogen : this is the material occurring in theold dark-coloured wood. The other is found in the younger and paler variety.According to the researches of Meier and Wimmer santalin is accompaniedby divers red and brown coloured matters, more soluble in water than santalinitself and the produ&s of its oxidation. This assertion is certainly substan-tiated by the fadt that the young twigs of the Pterocarpus santalinus are inter-nally yellow-coloured, and only become red by the adtion of the air.
Santalin exhibits the following properties :—It is a beautiful red crystallinepowder, almost insoluble in water, soluble in alcohol, ether, and acetic acid:the colouring matter is very readily withdrawn from the acetic acid solutionby albuminous substances, which retain it energetically; alkalies dissolvesantalin, yielding deep violet-red solutions, from which it is thrown down un*altered by acjds. Santalin fuses at 104°,