416 
stance they proceed from, require 
to pass through cold water, the 
steam of boiling water, or to be 
contined some time in cold vessels 
before they can be condensed, the 
change cannot be effected by any 
method hitherto known, because 
none of them is capable of making 
the vapour pass through water, or 
of confining it long enough for it 
to condense, without choaking up 
the draught of air necessary for the 
burning of the fires. My invention 
supplies this defect, by making a 
constant draught from the fires, and 
causing the vapour to pass through, 
or be retained in, proper vessels, a 
sufficient time for it to condense. 
This is effected by connecting the 
aperture of the chimney or chim- 
neys, with the condensing vessels, 
or chambers, by means of tubes or 
pipes ; then is to be placed, either 
between this connection, or behind 
the condensing vessels, any machine 
or machines, whose principle de- 
pends upon the known property of 
all fluids rushing in to fill up the va- 
cuum caused by their action ; that 
is to say, air-pumps, water-pumps, 
ventilators, bellows, air-machines, 
&c. These, however different their 
constructions, have all one common 
principle, and therefore the applica- 
tion of them, or others depending 
upon the same principle, to effect 
the purpose above mentioned, will 
be an infringement upon my said 
patent. The size, number, and con- 
struction of the condensing vessels, 
must depend upon the vapour to be 
decomposed, as some vapours are 
more difficult to condense than 
others, and therefore require a 
longer process, The apparatus be- 
ing thus fixed, the substances to 
yield the smoke, or vapour, are to 
be set on fire under the chimney or 
ANNUAL REGISTER, 1792. 
chimneys; and the machine, or 
machines, set in motion by either 
steam, engine, water, or horse- 
wheel, &c. The vapour will be 
drawn from the fires by the action 
of the machine, and made to pass 
through the condensing vessels, to 
be decomposed. There must be 
apertures at the end of the condens- 
‘ing-vessels, if the pumping-machine- 
is placed between them and the 
chimney, to open and shut, for the 
purpose of giving vent to the in- 
condensable airs, which will com- 
bine with the vapour in burning, 
and pass with them through the 
apparatus. If the machine is placed 
behind the vessels, there will be no 
occasion for those apertures. In 
witness whereof, &c. 
Specification of the Patent granted to 
Mr. Hector Campbell, of the Parish 
of St. Mary Magdalen, Bermondsey, 
an the County of Surrey, Chemist, 
for his Method of destroying the 
colouring Elements and Particles in 
coloured Rags, and other Materials 
used in muking Paper. 
Dated Nov. 28, 1792. 
FTO all to whom these presents 
shall come, &c. Now, know 
ye, that, in compliance with the 
said proviso, I the said Hector 
Campbell do hereby declare, that 
my said invention of an improved 
method of destroying and taking 
away all the carbonic, oleaginous, 
and colouring elements and par- 
ticles in linen, cotton, hemp, and 
in all coloured rags and other ma- 
terials used in making paper, in a 
manner hitherto unattempted in 
this kingdom, and at a much less 
expence than any method pow in 
use, is described in manner follow- 
ingi— 
