&60 Method of giving to Cotton and Linen Thread 
alkaline solution of alumine, pure and without any mix- 
ture : by immersing the skains, shades more or less dark 
will then be obtained according to the number of impreg- 
nations. 
To obtain, however, bright and at the same time uni- 
form shades, it will be better to employ three impregna- 
tions, properly weakening the alkaline solution. One may 
then impregnate three times successively in this concen- 
trated or weakened solution without previous washing : 
by these rnjeans the manipulations, which are often tedi- 
ous and troublesome, may be shortened ; but in this case 
it will be necessary to examine the solution from time to 
time, to see whether what the impregnated and dried 
skains discharge in it do not render it too strong. 
In re-dyeing shades of red, it will be necessary to as- 
certain first whether they have been brightened by means 
of boiling bran water, or by soap and alkalies. In the first 
dkse they will become darker, by still attracting colour- 
ing particles of the madder ; in the second they are weak- 
ened, and lose the excess of alumine, without which re- 
peated dyeing can produce no effect. The .removal of this 
excess of alumine may be prevented by substituting for 
soap and alkalies, 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. 
]Ieal Adrianople reds become much darker by re-dyeing 
them, and turn brown by the test of ebullition in water 
alkalized by ashes : these reds change only very little 
before they are re-dyed. In general, reds become brown 
more or less disadvantageous^ according to the time they 
have been boiled in brightening them. As the real Adri- 
anople reds have a strong smell, it is probable that the 
Turks employ fish oil, which they add directly to the 
alkaline solution of alumine, or mix with a ver^ weak ley 
of alkaline carbonate. 
