71' Method of making Soap of Wool. 
The ley, by the wool first dissolved in it, acquires a 
green colour; it afterwards grows black; and the soap, 
when cold, still retains a blackish green colour. 
This soap has been made use of, in every different 
manner, and under every form, in my manufactory for 
dyeing cottons ; and I am now satisfied that it may be em- 
ployed, instead of the saponaceous liquor we are accus- 
tomed to make from ley of soda and oil, for the purpose 
of preparing the cottons. I have constantly observed, 
that if such a quantity of this soap be dissolved in cold 
water as will render the water milky, and the cotton be 
worked therein, in the usual well known manner, it will, 
by being passed three times through the liquor, and dried 
each time, be as strongly disposed to receive the dye, as 
cotton which has been seven times passed through the sa- 
ponaceous liquors commonly used. This will not be 
thought very astonishing, when it is considered, that ani- 
mal substances are very fit for disposing thread and cot- 
ton to receive the colours with which they are to be dyed ; 
and that the intention of several of the operations to be 
performed upon them, previous to their being dyed, is 
merely to impregnate them with such substances. 
It is necessary to remark, that cotton, by being passed 
through a solution of this soap, acquires a grey tinge, 
very much like tbit which is given to it by aluming ; al- 
though the common saponaceous liquors give it a beauti- 
ful white colour. This grey colour, however, is no dis- 
advantage to cotton which is intended to be dyed, as 
we have already remarked with respect to woollen cloths. 
In confirmation of what I have said above, respecting 
the advantage to be derived from making use of this soap, 
I may add, that after having impregnated some cotton 
with it, according to the usual method, I made it pass 
through all the processes which wool undergoes, in order 
to be dyed of a scarlet colour. The consequence was* 
