160 Dr. Sciiunck on 



alcohol deprived the wool of the greater part of the yellow 

 colour, a faint tinge only being left. The deep yellow 

 alcoholic liquid obtained left on evaporation a reddish- 

 brown amorphous residue. This, on being treated with a 

 boiling solution of alum, dissolved in part, yielding a pink 

 fluorescent liquid, which had exactly the same colour, and 

 showed precisely the same absorption bands as a solution 

 of purpurin from madder in alum liquor. On adding hydro- 

 chloric acid to the pink solution and heating, the colouring 

 matter was precipitated in orange-coloured flocks, the 

 liquid becoming almost colourless. The flocks after being 

 filtered off and washed with water dissolved easily in 

 boiling alcohol, yielding a yellow solution, which, on spon- 

 taneous evaporation, left a quantity of dark yellow needles 

 arranged in rosettes. These needles dissolved in caustic 

 alkali, giving a cherry-red solution, which showed the 

 absorption bands of purpurin. The solution, on exposure 

 to air and light, became colourless. 



Some of the precipitated colouring matter, on being 

 employed in the usual way for dyeing a bit of calico to which 

 various mordants had been applied, yielded colours exactly 

 like those obtained with purpurin from madder, i.e., the 

 alumina mordant gave a bright red, the iron mordant dull 

 purple to black tints. The matter left undissolved, after 

 repeated treatment with boiling alum liquor, was still 

 highly coloured. It dissolved easily in alcohol, the solution 

 leaving on evaporation a brown amorphous residue, which 

 remained soft even after long standing. This residue con- 

 sisted for the most part of fatty matter, but it also contained 

 some colouring matter insoluble in alum liquor. That this 

 colouring matter was alizarin seemed probable, since the 

 colour which the mixture imparted to alkaline lye resembled 

 that of an alkaline solution of impure alizarin. 



These experiments lead to the conclusion that the red 

 colour of the fabric was produced by dyeing with some kind 



