the Adriaivople Red, and other fixed Colours. .34S 



In re-dyeing shades of red^ it will be necessary to ascer- 

 tain first whetlier they have been brightened by means of 

 boiling bran water, or by soap and alkalies. Jn the first 

 case they will become dai'ker, by still attracting colourincr 

 particles of the madder ; in the second they are weakened, 

 and lose the excess of alumine, without which repeated dye- 

 ing can produce no effect. The removal of this excess of 

 alumine may be prevented by substituting for soap and al- 

 kalies, to produce crimson shades, a portion of the alkaline 

 solution of alumine, which must be added to the bran water 

 towards the end of the brightening. Real Adrianople reds 

 become much darker by rc-dyeing them, and turn brown 

 by the test of ebullition in v/ater alkalized by ashes : these 

 reds change only very little before they are re-dyed. In 

 general, reds become brown more or less disadvantageously 

 according to the time they have been boiled in brightenino- 

 them. As the real Adrianople reds have a strong smell, it 

 is probable that the Turks employ fish oil, which thev add 

 directly to the alkaline solution of alumine, or mix with a 

 very weak ley of alkaline carbonate. 



The processes for dyeing Adrianople red can be infinitely 

 varied ; for in whatever manner and by whatever solvents, 

 whether acids or alkalies, the alumine may have been fixed 

 on the skains, \\'heu a light stratum of oil has been applied 

 reds more or less bright will be obtained, according to the 

 precaution employed in maddcring and brightening. 



It appears to me more difficult to explain the reason why 

 oils combine so easily with caustic alkalies to form soaps, 

 and do not admit of being mixed with concentrated leys of 

 alkaline carbonates, while they form a kind of artificial milk 

 with these leys when very much diluted, because one mio-ht 

 suspect a tendency to combination in such milky mixtures, 

 A mere suspension of the integrant oily moleculae, which 

 would take place rather in the diluted ley than in the same 

 ley more concentrated, is equally difhcuk to be explained. 



It remains that I should rectify an injury done to the pro- 

 cess for dyeing real Adrianople red in other manufactories. 

 What was shown to me was only of the most inferior qua- 

 lity. I have seen some since equal to the finest and most 

 durable that can be produced. So that I am inclined to 

 think that the mercluuidize of the Turks, like that of all 

 other nations, is suited to the price which Uie purchaser 

 wishes to give. 



I must observe also, that among my burnt cotton there 

 was some both times which had been impregnated v, ith a 



weak 



