go2z On ihe Process of Bleaching with 
were stratified; and the liquor being poured om 
them, the cisterns were closed with lids. But this 
method was soon found to be defective, as the li- 
-quor could not be equally diffused ; the pieces were, 
therefore, only partially bleached, being white in 
some parts and more or less. coloured in others. 
Various other contrivances were tried without suc- 
cess, till it was discovered that an addition of al- - 
kali to the liquor deprived it of its suffocating ef- 
fects, without destroying its bleaching powers. The 
process began then to be carried on in open vessels, 
and has been continued in this manner to the present 
period. The bleacher is now able to work his pieces 
‘in the liquor, and to expose every part of them to 
its action, without inconvenience. This advantage 
is unquestionably great ; but it is diminished by the 
heavy expence of the alkali, which is entirely lost, 
It is moreover to be feared, that the alkali which is 
added to the liquor, though it does not destroy its 
power of bleaching, may diminish it; because a so- 
Jution of the oxygenated muriat of potash, which 
differs from the alkaline bleaching liquor, in nothing 
but in the proportion of alkali, will not bleach at 
all. This is a well known fact, from which we 
might infer, that the oxygenated muriatic acid will 
lose its power of destroying the colouring mat- 
ter of vegetable substances, in proportion as it be- 
comes neutralized by an alkali. But as we should 
‘not content ourselves with inferences however play. 
