USEFUL PROJECTS. 
ing: I the said Hector Campbell 
having practised, and still practis- 
ing, under circumstances, the me- 
thod invented by the French 
(which I believe I frst adopted for 
absolute business in England) of 
saturating atobof water, or aoy 
other fit receiver, with oxygenated 
muriatic acid, and applying this 
liquor to a variety of bleachable 
articles; in the year one thousand 
seven hundred and ninety-one, I 
took it up as a manufactory, and 
applied it to whitening coloured 
brown Hamburgh and other cheap 
rags, both whole and in a reduced 
state, for the purposes of selling 
rags, pulp, and other materials for 
meking paper. But notwithstand- 
ing the previous use of an alkaline 
ley, and, when the liquor was put 
to the article, the revolution of the 
vessels, and the variety of plans to 
excite internal motion, suchas sticks 
to catch and divide, internal re- 
volving and up-and-down powers, 
and levers to agitate and divide, all 
of which I pr«ctised, I still found 
the op+ration in preparing the said 
materials for making paper, in point 
of time, labour, inequality ot beau- 
ty, and bleaching only to a cer- 
tain degree, extremely imperfect. 
Therefore, from numerous con- 
siderations and experiments, and at 
@ great expence of time, labour, 
and money, I discovered the fol- 
lowing improved method: Take 
of rag, coloured or not, or pulp, or 
any cotton, flaxen, hempen, or 
other material fit to make paper, 
and let the first consideration be 
for what you want it, that is, how 
valuable you intend to make the 
article: wash the said material for 
making paper. When the material 
for making paper is wanted for 
» making an inferior sort of paper, it 
Vo. XXXIV. 
417 
does not require to be passed thro” 
au alkaline ley previous to bleach- 
ing, but may be bleached in the 
manner hereinafter described.— 
Should the material be wanted for 
making better paper, it may be 
passed through an alkaline ley, 
cleansed from it, and then bleached 
in manner hereinafter described ; 
but this process of previously pass- 
ing the material for making paper 
through an alkaline ley, will not 
bleach, in one bleaching, beyond 
a certain degree, extremely inade- 
quate to constitute superior excel- 
lence. Therefore, to bleach the 
material in the best manner, take 
of either of the said materials for 
making paper, and either pass it 
through an alkaline ley previously 
or not; then bleach it in the man- 
ner hereinafter described; then 
boil it in an alkaline ley (a solu- 
tion of caustic pot-ash will answer 
the purpose) : the time of boiling 
and the strength of the ley must be 
acjusied by the nature and quality 
of the material, and the purpose it 
is wanted for; then wash the alkali 
from the material, and present it 
again to be bleached. This pro- 
cess will be sufficient ; but, to bring 
the material to a great perfection, 
it may be repeated alternately ; 
but, after the material has been 
alkalized, passing it through, or 
having any thing to do with what 
are termed the sours, or vitriolic 
acid and water, or any other acid 
and water, is unnecessary. Fine 
materials are considerably improved 
by bleaching, and then boiling in 
alkali, and then bleaching again; 
but more especially coarse, white, 
or brown materials, such as have 
never been coloured, will never 
so well have their carbonic, oleagi- 
nous and ligneous elements and 
Dd particles 
