and Dyeing Turkey Red, 215 
carmelite, burnt bread, bronze, &c. As tbe preliminary 
preparation of tbe skains by the oily alkaline solution of 
alumine might be too expensive for some of these colours, 
the process I described in the Annales de Chimie for the 
year 1792, p. 250, may be substituted in its stead. This 
process consists in treating the skains alternately with 
soap and sulphate of alumine, the excess of the acid of 
which has been saturated with one of the alkaline carbo- 
nates or with lime : this method is very expeditious. In 
the course of a day, especially in summer, the skains may 
be prepared and dyed red as well as other colours ; 
which, for the most part, may be subjected to ebullition, 
and will bear clearing with bran for a quarter or half 
hour, and even some of them for a whole hour. It is al- 
so to be observed that there are none but madder colours, 
the alumine and oxide of iron bases of which have been 
fixed on the stuffs by means of the oily alkaline solution, 
that can acquire perfect fixity by the action of heat of 
boiling water ; and that the fixity is very inferior in all 
madder colours the earthy and ferruginous bases of 
which have been applied to stuffs by means of acid soh 
vents. 
Alumine, fixed in abundance on cotton or linen stuff 
by means of a highly concentrated alkaline solution, a t~ 
tracts very easily the colouring parts in the process of 
maddering. The case is not the same when the same 
earth is applied by the most highly concentrated acetic 
solution of alumine ; and it is absolutely impossible to fi- 
nish maddering at one time, even when a profusion of 
madder is employed, and the operation is repeated three 
and even four times.* This circumstance “will give rise 
to new and interesting experiments ; but my observations 
prove in the mean time that maddering, in general, re 
quires to be managed with the nicest attention. 
* Concentrated acetic solution of oxide of iron is attended with nearly the 
same difficulties. 
