A MODE OR MODES OF MANUFACTURING MINERAL ALKALI AND VEGETABLE ALKALI, AND THE APPLICATION THEREOF, SO FAR AS RELATES TO MINERAL ALKALI, BY WAY OF IMPROVEMENT ON OR ADDITION TO OTHER MODES HERETOFORE KNOWN OR IN USE, BUT MORE PARTICULARLY IN THE MANUFACTURE OF KELP
Year: 1819

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
ATTWOOD, of Bridge Street, Blackfriars, in the City of London, Window
Glass Manufacturer, send greeting.
WHEREAS His most Excellent Majesty King George the Third, by His
Letters Patent under the Great Seal of Great Britain, bearing date at West-
minster, the Twenty-second day of June, in the fifty-ninth year of His reign,
did, for Himself, His heirs, and successors, give and grant unto me, the said
Charles Attwood, His especial licence that I, the said Charles Attwood, my
executors, administrators, and assigns, or such others as I, the said Charles
Attwood, my executors, administrators, or assigns, should at any time agree
with, and no others, from time to time and at all times during the term of
years therein expressed, should and lawfully might make, use, exercise, and
vend, within England, Wales, and the Town of Berwick-upon-Tweed, and
also within all His Majesty's Colonies and Plantations abroad, my Invention
of "A MODE OR MODES OF MANUFACTURING MINERAL ALKALI AND VEGETABLE
ALKALI, AND THE APPLICATION THEREOF, SO FAR AS RELATES TO MINERAL ALKALI, BY
WAY OF IMPROVEMENT ON OR ADDITION TO OTHER MODES HERETOFORE KNOWN OR IN
USE, BUT MORE PARTICULARLY IN THE MANUFACTURE OF KELP;" in which said
Letters Patent there is contained a proviso obliging me, the said Charles
Attwood, by an instrument in writing under my hand and seal, particularly to
describe and ascertain the nature of my said Invention, and in what manner
the same is to be performed, and to cause the same to be inrolled in His

page_text: Majesty's High Court of Chancery within six calendar months next and
immediately after the date of the said recited Letters Patent, as in and by the
same, reference being thereunto had, will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Charles Attwood, do hereby declare that the nature of my said Invention, and
the manner in which the same is to be performed, are as follows (that is to
say)-
The same doth consist, in so far as relates to mineral alkali, in the manu-
facture thereof from the substance known in chemistry by the name of sul-
phuret of soda, and in so far as relates to vegetable alkali, in the manufacture
thereof from the substance known in chemistry by the name of sulphuret of
potash, by the following process, which is the same with regard to both (that
is to say), by exposing them separately (until such time as the effect of con-
verting such sulphurets respectively into mineral alkali and vegetable alkali be
perfectly produced,) either dry, or in a state of solution in water, in proper
chambers, vessels, cisterns, or reservoirs, to the action of carbonic acid, or to
an atmosphere consisting in the whole or in part thereof, produced by the
combustion of charcoal or other proper carbonaceous matter, or by the calcina-
tion of limestone or other proper calcareous earth, or in part by both, or by the
fermentation of vegetable matter, or any other cheap and convenient mode,
whereby such sulphurets are gradually but completely decomposed and con-
verted into such alkalies respectively, such chambers or vessels being
furnished with proper openings and vents for receiving and changing such
acid or air containing such acid as may be required. And I do declare my
said Invention to be applicable to the conversion of sulphuret of soda and
sulphuret of potash into mineral alkali and vegetable alkali respectively,
howsoever such sulphurets may exist or be produced, and consequently, by way
of improvement on or addition to any other mode or modes of manufacturing
mineral alkali, with the product or result of which any sulphuret of soda may
remain combined, as is often the case with regard thereto; and often also in
the case of barilla, and still more extensively in that of kelp, to both of
which therefore, and particularly to the latter, the utility of my Invention in
like manner applies. And for the more perfect and complete explanation of
my said Invention, I do further declare, that when I do expose the sulphuret
of soda, or the sulphuret of potash, or any substance containing the same or
either or both of them in the dry way to the action of carbonic acid as afore-
said, I do find it useful so to dispose the same as to expose as large a surface
as conveniently may be to the action of such carbonic acid; and I do likewise
find it useful to spread it lightly and evenly about, and that the thinner and

page_text: more superficially the same is spread, and the more finely it is comminuted,
the more quickly is the effect produced; but that considerable variation may
be admitted in both respects, according to convenience, without any material
disadvantage beyond a prolongation of the operation. And I do find that this
operation may be very well performed in any common room or chamber, of
brick or other materials, in which it is advantageous to have different floors or
shelves disposed successively at short distances above each other from the
bottom to the top, with sufficient spaces or interstices at proper points and
places to allow of and promote the change and circulation of the carbonic
acid in the state of gas through any part; it being necessary besides that
such chamber be furnished with a vent or vents for the same purpose, and
with proper openings for the easy placing and removing of the materials, and for
stirring or changing the position thereof, which is of service when it is desired
to produce a saving in point of time. And further, I do find that when the
quantity of sulphuret of soda or of sulphuret of potash respectively by this
mode acted on in the dry way constitutes ever so small a proportion of the
mass with which it may be mixed, as in the case of barilla or kelp for
instance, it is still not necessary that any previous separation should be made
thereof, but the gross mass, comminuted or broken down as far as may be
convenient, may be treated by this mode with the same ultimate effect as if it
consisted of either of such sulphurets in a state of purity. Aud I do further
declare, that when I do operate upon either or both such sulphurets in a state
of mixture with other substances, or otherwise in the humid way, or in a state
of solution in water, I do find the operation to proceed with the greater quickness
by exposing as large a surface of the solution as I find practicably con-
venient to the action of the carbonic acid gas; and accordingly such operation
is best performed in shallow vessels, cisterns, or reservoirs, the exact depth
of which I do not find to be important, but generally I do consider that
cisterns of brickwork or other materials sufficiently secured from leakage,
of the depth of from one to three feet, and covered in at the additional
height of from one to two feet, very suitable and convenient. And further
I do declare, that although the rapidity of the operation both in the
humid and in the dry ways is capable of being very considerably increased by
the application of the carbonic acid under a greater pressure than that of the
atmosphere, and although the rapidity of such operation is likewise capable
of being increased, when performed in the humid way, by agitation of the
solution or by forcing the carbonic acid through the same in a stream or
streams, yet I do doubt whether the use of any such process or processes be
in all respects and under all circumstances so economical as the exposure of

page_text: as large a surface of the material as conveniently may be, whether in solution
or otherwise, in such chambers or cisterns as I have described, to an atmo-
sphere or gentle current of carbonic acid in the state of gas, or of air con-
taining as large a proportion thereof as may conveniently be procured, and at
as low a temperature as it can easily be brought to; and I do in all cases,
rather than employ such gas at a temperature considerably higher than that
of the common air, have recourse to passing it into the chambers or cisterns
in which the same is to be employed through a pipe or worm surrounded by
cold water, or to any other such simple and effectual contrivance, in which
there may be as little difficulty and expense as possible. And with regard to
the mode or modes whereby I do produce and collect such carbonic acid, it is
sufficient to receive the air containing it from the flue of any small stove or
furnace, so formed as that such air must necessarily have passed through the
body of the fire, whereby a quantity of such carbonic acid is always generated;
or it is sufficient to receive the air from any furnace or kiln, or from any
retort or vessel wherein such acid produced by the calcination of chalk or
limestone, or other proper calcareous earth, either mixed with the further
quantity produced by the combustion of the fuel employed or otherwise, or to
receive the air from any vessel in which vegetable matter may be kept in a
state of fermentation, or from any other cheap or convenient source thereof.
And I do further declare, that it is not of any considerable consequence
whether such acid be or be not in a state of purity, only it is desireable that it
be not mixed with any considerable quantity of oxygen gas, and more parti-
cularly with any other acid in the state of gas or otherwise, on which account
it is adviseable, if it be produced in whole or in part by combustion, as before
said, to use no fuel containing any pyritous or other sulphureous matter.
And to prevent any misunderstanding of my meaning, I do desire it to be
remembered that I have in the course of this my Specification made use of
the terms sulphuret of soda and sulphuret of potash with reference not only
to the substances generally and strictly so called, and which are said to exist
only in a state of dryness, but also with reference to such substances in such
state or states of combination with hydrogen as they enter into when they
exist in solution in water, because the nature and true names of some
such combinations do not appear to me to have been hitherto completely
settled.
In witness whereof, I, the said Charles Attwood, have hereunto set my
hand and seal, this Twenty-first day of December, in the year of our
Lord One thousand eight hundred and nineteen.
CHARLES ATTWOOD. (L.S.)

page_text: AND BE IT REMEMBERED, that on the Twenty-first day of December,
in the sixtieth year of the reign of His Majesty King George the Third, the
said Charles Attwood came before our said Lord the King in His Chancery,
and acknowledged the Instrument aforesaid, and all and every thing therein
contained and specified, in form above written. And also the Instrument
aforesaid was stamped according to the tenor of the Statute made in the
fifty-fifth year of His said Majesty's reign.