A METHOD OR METHODS OF DISENGAGING AND OBTAINING A MINERAL OR FOSSIL ALKALI, OR SODA AND VEGETABLE ALKALI, OR PEARL OR POT ASH, FROM NEUTRAL SALTS COMPOSED OF THOSE ALKALIES AND AN ACID, OR FROM THE SOLUTIONS OF THOSE SALTS; THAT IN PROCESSES PREVIOUS TO THE DISENGAGEMENT OF THOSE ALKALIES, OR IN PROCESSES CONNECTED THEREWITH, SEVERAL ARTICLES ARE DISENGAGED OR FORMED WHICH MAY BE COLLECTED AND APPLIED TO SEVERAL VALUABLE PURPOSES
Year: 1795

page_text: EARL OF DUNDONALD'S SPECIFICATION:
TO ALL TO WHOM THESE PRESENTS SHALL COME, ARCHIBALD
Earl of DUNDONALD sends greeting.
WHEREAS I, the said Archibald Earl of Dundonald, did, by my petition,
humbly represent to His present most Excellent Majesty King George the
Third that I had, by long study and at a great expence, discovered, invented,
improved, and brought to practical use, "A METHOD OR METHODS OF DISENGAGING
AND OBTAINING A MINERAL OR FOSSIL ALKALI, OR SODA AND VEGETABLE ALKALI, OR
PEARL OR POT ASH, FROM NEUTRAL SALTS COMPOSED OF THOSE ALKALIES AND AN
ACID, OR FROM THE SOLUTIONS OF THOSE SALTS; THAT IN PROCESSES PREVIOUS TO THE
DISENGAGEMENT OF THOSE ALKALIES, OR IN PROCESSES CONNECTED THEREWITH, SEVERAL
ARTICLES ARE DISENGAGED OR FORMED WHICH MAY BE COLLECTED AND APPLIED TO
SEVERAL VALUABLE PURPOSES;" I, therefore, humbly prayed His said Majesty to
grant unto me, my executors, administrators, and assigns, His Royal Letters
Patent for the sole use and benefit of the said Inventions within that part of His
said Majesty's Kingdom of Great Britain called England, His Dominion of
Wales, and Town of Berwick-upon-Tweed, and Colonies abroad, pursuant to the
Statute in that behalf made and provided; and His said Majesty, being willing
to give encouragement to all arts and inventions which might be for the public
good, was graciously pleased to condescend to my request; and, therefore, by
His Letters Patent bearing date at Westminster, the Twenty-eighth day of
February, in the thirty-fifth year of His reign, of His especial grace, certain
knowledge, and mere motion, for Himself, His heirs and successors, did give
and grant unto me, the said Archibald Earl of Dundonald, my executors, ad-
ministrators, and assigns, His especial licence, full power, sole privilege and
authority, that I, the said Archibald Earl of Dundonald, my executors, ad-
ministrators, and assigns, and every of us, by myself and themselves, and by

page_text: mine and their deputy or deputies, servants, or agents, or such others as I, the
the said Archibald Earl of Dundonald, my executors, administrators, or
assigns, should at any time agree with, and no others, from time to time and at
all times thereafter during the term of years therein expressed, should and
lawfully might make, use, exercise, and vend, my said Invention within that
part of His said Majesty's said Kingdom of Great Britain called England,
His Dominions of Wales, and Town of Berwick-upon-Tweed, and Colonies
and Plantations abroad, in such manner as to nic, the said Archibald Earl
of Dundonald, my executors, administrators, and assigns, or any of us,
should in our discretion seem meet, and that I, the said Archibald Earl
of Dundonald, my executors, administrators and assigns, should and lawfully
might have and enjoy the whole profit, benefit, commodity, and advantage
from time to time coming, growing, accruing, and arising by reason of the said
Invention for and during the term of years therein mentioned, to have, hold,
exercise, and enjoy the said licence, powers, privileges, and advantages therein-
before granted or mentioned to be granted unto me, the said Archibald
Earl of Dundonald, my executors, adiiors, and assigns for and during and
unto the full end and term of fourteen years from the date of the said
Letters Patent next and immediately ensuing, and fully to be compleat and
ended according to the Statute in such case made and provided; in which
said Letters Patent is contained a proviso that if I, the said Archibald Earl
of Dundonald, should not particularly describe and ascertain the nature of my
Invention, and in what manner the same is to be performed, by instrument in
writing under my hand and scal, and cause the same to be inrolled in His
Majesty's High Court of Chancery within six calendar months next and im-
mediately after the date of the said Letters Patent, that then the said Letters,
and all liberties and advantages whatsoever thereby granted, should utterly
cease, determine, and be void, anything therein contained to the contrary
thereof in anywise notwithstanding, as in and by the said Letters Patent,
relation being thereunto had, may more fully and at large appear.
NOW KNOW YE, that I, the said Archibald Earl of Dundonald, in com-
pliance with the said proviso, do hereby describe and ascertain the nature of
my said Invention, and declare that the method or methods of disengaging
and obtaining a mineral or fossil alkali or soda and vegetable alkali or pearl
or pot ash from neutral salts composed of those alkalics and an acid, or from
tho solutions of those salts, is and are fully described in this Specification, as
likewise are the method or methods of performing other processes to which
these Patents have reference under the words-[that in processes previous to
the disengagement of these alkalies, or in processes connected therewith,

page_text: several valuable articles are disengaged or formed which may be collected and
applied to various valuable purposes].
In this Specification it will be necessary to begin with the description of the
processes referred to in the affidavit and petition, as previous to or preparatory
to the disengagement of those alkalies. That is, I first prepare and collect the
neutral salts, consisting of an alkali and an acid, and I then decompose those
neutral salts and disengage from them mineral alkali, or soda and vegetable
alkali, or pearl or pot ash. My intentions likewise were, by the method of
wording my affidavit and petition, to reserve to myself a power of manufac-
toring and disposing of the several articles made in my different processes in a
more or less finished state, particularly Glauber's salt, or the sulphat of soda
and mineral alkaline, hepar or sulphuret of soda, articles which, by experi
ments I had made, I had found might be used to advantage in various pro-
cesses, particularly as manures or saline stimulants to promote the growth of
vegetables in certain soils. My methods or processes for disengaging and
obtaining alkaline salts from neutral salts, consisting of an alkali and an acid,.
are numerous. It will require a long and detailed account to describe them
fully, as well as to describe the various articles formed or disengaged in pro-
cesses previous to the disengagement of the alkali, or in processes connected
therewith. Prudential considerations made it necessary that in my affidavit
and petition I should study brevity as much as possible; at the same time, that.
what was stated in the affidavit and 'petition might read with and be fully
explained in the subsequent Specification. And now that the Letters Patent:
have been obtained, I shall proceed with fidelity and accuracy to describe
my different processes, knowing that not only my duty to the public requires
it, but that it is my interest to do so to prevent others from encroaching on.
my Patents or raising a superstructure on my foundation.
I shall now proceed, first, to give an index of my different processes,
stating what I claim as my discoveries included in the affidavit and petition.
And, lastly, I shall give the fullest possible detailed account of each process,
and of the article or articles formed and capable of being collected.
INDEX.
1st. The first and most important of the processes is the making Glauber's
Lese neutral salts consisting of an alkali

page_text: .
Secondly. The decomposition of Glauber's salt or sulphat of soda, obtaining
from it hepar sulphuris or sulphuret of soda, and mineral alkali or soda, either
in a mild or caustic state.
Thirdly. The decomposition of muriate of potash or digestive salt of sylvius,
and preparation from it of sulphat of potash or vitriolated tartar.
Fourthly. The procuring from the sulphate of potash either sulphuret of
potash or vegetable alkaline hepar, or mild or caustic vegetable alkali. The
alkaline salts or sulphurets thus formed or prepared may be applied to
various purposes, particularly for the decomposition and disengagement of
mineral alkali or soda from Glauber's salt or sulphat of soda. This process or
application of the vegetable alkali and sulphuret procured from muriat of
potash, digestive salt, or from sulphat of potash or vitriolated tartar, in my
method or methods, is not to be understood to be limited or confined to the
decomposition of sulphat of soda or Glauber's salt made according to my
processes, but embraces and includes the decomposition of Glauber's salt or
sulphat of soda in whatever manner it has been made or procured.
Fifthly. The sulphat of potash or vitriolated tartar, reproduced in the
decomposition of the Glauber's salt or sulphat of soda, is recovered by me after
each process in the state of an alkaline salt or saline matter fit to decom-
pose more Glauber's salt or sulphat of soda, and to disengage from it mineral
alkali.
Sixthly. The decomposition of or change produced on sulphat of barytes
or terra ponderosa; the result of this preparation to be applied to the decomposi-
tion of sulphat of potash or vitriolated tartar, and sulphat of soda or Glauber's
salt, or to the decomposition of preparations containing these salts or their
solutions. The sulphat of barytes reproduced in this process may be recovered
and made to undergo again the same process, so as to fit it for the decompo-
sition of more sulphat of potash or vitriolated tartar, or sulphat of soda or
Glauber's salt, or preparations or solutions containing these salts.
Lastly. The decomposition of muriat of soda or sea salt, or salts or sub-
stances containing sea salt, by alkaline salts prepared by me, or according to
my processes.
I shall now proceed to describe these processes and the nature of the
different articles or saline matters formed or obtained.
General Description of the Glauber's Salt or Sulphat of Soda Process.-
I havo discovered that sea salt, or muriat of soda, is decomposed by sulphat of
alumine or alum, by sulphat of iron, green vitriol, or vitriol of iron, and by
sulpliat of magnesia or Epsom salt, with the aid of heat, when a due proportion

page_text: of clay or ferruginous argillaceous earth is mixed with the salts which are
intended to be operated upon. I have likewise discovered that muriat of soda
or sea salt is decomposed in considerable proportion by sulphat of magnesia or
Epsom salt, with the aid of heat, without the intervention of clay or argillaceous
earth. I have likewise discovered that muriat of soda or sea salt may be
decomposed by sulphat of lime or gypsum, with the aid of heat, when a due
proportion of clay or argillaceous earth containing much iron is mixed with
the sea salt and gypsum or sulphat of lime.
The above account of my discoveries and processes is intended by me to
embrace and include not only all the saline matters above mentioned when
used singly, but likewise when these saline matters are found mixed, or when they
are mixed together in different proportions, as when they are contained in alum
rock or schist, calcined or uncalcined, in alum raw liquor obtained by lixiviat-
ing alum rock or schist, calcined or uncalcined, lixiviated either with fresh or salt
water in alum boiled liquor, mother liquor, alum washings, or tun liquor, or in
alum slam, or the refuse saline matters of alum works, in vitriolic, sulphureous,
or pyrituous schist or substances, or in their solutions, such as are or may be
used for making sulphuric or vitriolic salts with metallic or earthly bases. In
this description I include the saline matters arising from a mixture of sub-
stances capable of producing any of the above saline matters, such as sulphur
and iron, or sulphur and the earth of iron, with or without water.
And lastly, under the article of niuriat of soda or sea salt, I include rock
or fossil salt, and all other substances containing it, such as kelp, sandiver or
the refuse from glass works, soapers' leys, salts, ashes, or refuse materials, or
the solutions of any of these substances.
Particular or detailed Description of the Glauber's Salt or Sulphat
of Soda Process.-Take a given quantity of sea salt, rock salt, or
muriat of soda, or any salt containing sea salt or muriat of soda, or sea
water, or solutions of salts containing muriat of soda or sea salt; add to any
of the above salts, or their solutions, such a quantity of sulphat of alumine
or alum, or sulphuret of alumine, sulphat of iron or green vitriol, or
vitriol of iron, sulphat of magnesia or Epsom salt, or sulphuret of magnesia,
or salts, or saline mixtures, or solutions containing any one or more of these
salts or substances, as that the sulphuric acid or vitriolic acid contained in the
particular substances, salt, or salts, or solutions used shall be sufficient to produce
the effect hereafter described. Let the inuriat of soda or other salts first
mentioned, or their solutions and the sulphuric substances or salts above de-
scribed, or their solutions, be mixed together; add to or mix with them a

page_text: due proportion of argillaceous earth or clay, or rather ferruginous argillaceous
matter. The materials are then to be dried or deprived of moisture, ground
to a powder, the finer the better, and thon submitted to the action of heat in
a reverberatory or other furnace, pot, or crucible until the muriatic acid is
expelled. The residuam after calcination consists of sulphat of soda or
Glauber's salt of clay, and the earth of iron or clay, and the earth of magnesia,
according to the nature of the sulphuric salt or salts used in the process. The
Glauber's salt or sulphat of soda is to be separated by lixiviation or washing.
It may be crystalized or boiled to dryness, or kept in a state of solution, accord-
ing to the particular purposes to which it is to be applied. The carthy matter
when it contains much iron, when properly levigated, washed, and dried, may
bo used as a pigment. The muriatic acid expelled in the before described
process may be collected, using the vessels or apparatus adopted for that pur-
pose by chemists or others that may be found proper for the purpose; or the
muriatic acid may be applied for making muriat of ammoniac or sal ninmoniac
by conducting or conveying the muriatic acid or muriatic acid gas with volatile
alkali or volatile alkaline gas obtained from cold tar, water, bones, soot,
urine, or other materials into a proper receiver.
This Patent is intended to include all and every one of the products above
mentioned; I likewise decomposo muriat of soda or sea salt, or solutions of
salts containing muriat of soda, by the means of sulfat of magnesia or Epsom
salt without the use of clay or carth of iron, simply by the application of a
properly regulated degree of heat; but the decomposition in this process is not
so complete as in the processes above mentioned. Muriat of soda or sea salt
is likewise in part to be decomposed by sulphat of lime or gypsum, with the aid
of heat, when a due proportion of ferruginous clay is used, preceding in all
other respects in those two last mentioned processes as when sulphat of iron, of
clay, or of magnesia is used. The more free the clay or argillaceous earth
used in the above described processes is from quartzose or siliceous earth, the
better it answers for the promoting the expulsion of the muriatic acid. What
I have found to answer best is alum schist or rock, particularly that part which
abounds most in sulphate of iron or vitriol of iron. The more earth of iron it
contains the more readily and completely the process succeeds. I have operated
with so large a proportion of the earth of iron that, to guard my Patent
from encroachment, I must here, to the former directions for the addition of
clay or argillaceous earth to muriat of soda or sea salt, and any of the before
mentioned sulphuric or vitriolic salts, subjoin the words earth of iron, in which
case my Specification will run clay, ochre, or earth of iron, or clay and ochre
or earth of iron, in any different proportions.

page_text: Decomposition or Sulphat of Soda or Glauber's Salt, and Disengagement of
Mineral Alkali or Soda.-Take sulphat of soda or Glauber's salt made in any
of the above described processes, add to it such a proportion of pearlash, potash,
or vegetable alkaline salt as will combine with the sulphuric acid of the sulphate
of soda or Glauber's salt; let the liquor be properly concentrated by boiling or
evaporation, and the separation of the sulphat of potash or vitriolated tartar be
performed by crystallization and cooling. The proportion of the mineral alkali
adhering to or which humects the surface of the crystals of sulphat of potash
or vitriolated tartar may be separated by washing the crystals of sulphat of
potash or vitriolated tartar with a small proportion of cold water. The mineral
alkali may then be crystallized or boiled to dryness, or submitted or not, as
may be required, to the action of a reverberatory or other furnace.
I do not lay claim to the exclusive privilege of applying pearlash or pot ash
or vegetable alkali for the disengagement of mineral alkali from sulphut of
soda or Glauber's salt, a process well known to every chemist; but I lay claim
to the exclusive application of pearl ash or pot ash or vegetable alkali for the
separation of the alkali contained in sulphate of soda or Glauber's salt, when
the sulphat of soda or Glauber's salt is made according to any of my precesses.
It is the more necessary to insert this claim here as I may have occasion to
dispose of large quantities of sulphat of soda or Glauber's salt, or preparations
from sulphat of soda or Glauber's salt, for other purposes than for making
mineral alkali, and it is intended that the claim here lodged shall guard my
interest against those who should attempt to manufacture mineral alkali in the
manner above described, or in any manner or method from the sulphat of
soda or Glauber's salt prepared by me or by others under my Patent, and
sold or disposed of.
Thirdly. The decomposition of muriat of potash or digestive salt of sylvius,
and preparation from it of sulphat of potash or vitriolated tartar, comes next
in order to be described, and is to be performed in all respects and with the
same materials as have been stated and enumerated for preparing Glauber's
salt or sulphat of soda from muriat of soda or sea salt, substituting only
muriat of potash for muriat of soda or sea salt. The results or products of

page_text: caustic vegetable alkali. These are to be procured by several different processes;
and this sulphuret and these alkalis may be applied for the decomposition of
sulphate of soda or Glauber's salt. The same processes may be extended to the
procuring sulphuret of soda or mineral alkaline hepar, as well as mild and
caustic mineral alkali, from sulphat of soda or Glauber's salt. Tako sulphat
of potash or vitriolated tartar, produced in the last process, or produced in
disengaging the mineral alkali from sulphat of soda or Glauber's salt, or take
sulphat of potash prepared in any other manner, add to it a due proportion of
carbonaceous, ligneous, vegetable, or inflammable matter. Let the materials be
brought to fusion in a pot, crucible, reverberatory or other furnace, and the
fusion continued until a proper hepar or hepatic alkaline salt is formed. Let the
melted matter be run or taken out of the furnace, pot, or crucible. Let it cool;
break the hepar into pieces or grind it to powder. To sulphate of soda or
to a solution of sulphat of soda male in any of the before described processes,
for to sulphat of soda or solution of sulphat of soda made in any other process
or any how procured, add as much of the hepar, or alkaline liver of sulphur, or
hepatic alkaline salt above described, as shall be requisite to decompose the
sulphat of soda. The sulphat of potash formed in the process may be separated by
priority of cystallization. After the separation of the sulphate of potash there
will remain a carbonate of soda or mild mineral alkali, and a sulphuret of soda
or mineral alkali liver of sulphur. These remaining salts may be applied in
the manufacture of soap, altho' the alkali is not so pure as that which is
procured in processes formerly and afterwards to be described.
Fifthly. Under this head are included a variety of processes for recovering
and procuring a perfectly pure vegetable alkali from sulphat of potash or
vitriolated tartar, however procured; and these processes may also be applied
for making a sulphuret of soda, or mineral alkaline, liver of sulphur, from
sulphat of soda or Glauber's salt made in any of my different processes, as well
as for making from sulphat of soda or Glauber's salt prepared in my processes,
or made or procured in any other manner, a mild or caustic mineral alkali
or soda, substituting only where necessary the words sulphat of soda or
Glauber's salt, and sulphuret of soda or mineral alkaline hepar, for sulphat
of potash or vitriolated tartar, and sulphuret of potash or vegetable alkaline
hepar, respectively.
Ligncons Process in the Wet Way in Close Vessels.-Take hepar or liver
of sulphur made from sulphat of potash or vitriolated tartar, dissolve it, when
newly made, in water; add a due proportion of sawings of wood, or any
ligucous or vegetable matter, their juices, gums, resins, or extracts, or vegetable

page_text: matter, such as peat, or the hepar or sulphuret or liver of sulphur, may be
mixed with the before described vegetable substances, and then dissolved in a
duc proportion of water. The materials, when thus mixed from the action of
air, and in that situation, a due degree of heat may be applied to them. The
liquor, after standing a due time, is to be drawn of, and the residuum repeatedly
lixiviated with water to separate the saline matter. The lixivia or leys must
be boiled to a due consistence, the proportion of sulphat of potash (if any)
contained in them must be separated by crystallization, and the remaining
liquor must be boiled to dryness, and then calcined in a reverberatory or other
furnace. The saline matter remaining after calcination will consist of mild
vegetable alkali, or carbonate of potash.
Ligneous Process in the Wet Way in Open Vessels.-This process is per-
formed with the same materials, and is in all respects similar to the process
last described, excepting that the access of air is not excluded. A less proportion of
vegetable alkali and a larger proportion of sulphat of potash or vitriolated tartar
is obtained in this than in the last described process, which is therefore preferable.
Ligneous Process in the Dry Way-Take hepar, or liver of sulphur, or
sulphuret recently made from sulphat of potash or vitriolated tartar; dissolve
it in water; draw off the clear liquor, and mix it with a due proportion of
sawings of wood, or any ligneous or vegetable matter, their juices, gums, resins,
or extract or vegetable matter, such as peat; boil the materials to dryness, or other-
wise bring them to a dry state; submit them to calcination in a pot, crucible,
or reverberatory or other furnace; lixiviate the ashes; boil down the lixivium
or leys to a dry salt, which will consist of mild vegetable alkali with a propor-
tion of sulphat of potash or vitriolated tartar. The salts may be separated by solu-
tion and priority of crystallization. The preparations of sulphat of potash, or vitrio-
lated tartar, according to these three ligneous processes, may be used with greater
advantage than hepar or sulphuret of potash in decomposing sulphat of soda or
Glauber's salt or muriat of soda and disengaging from them the mineral alkali.
Ligncous Preparation of Sulphat of Soda or Glauber's Salt.-Let sulphat
of soda or Glauber's salt be made into a hepar or sulphuret, and treated either
by the first, second, or third ligneous process directed for the sulphat of potash
or vitriolated tartar. The result will be carbonat of soda or mild mineral
alkali, and sulphat of soda or Glauber's salt. But I do not so much recommend
this process, from the difficulty of separating the mineral alkali from sulphat of
seda. But, as the same objection does not apply to the separation of mineral
alkali from sulphat of potash or vitriolated tartar, I-recommend that the above
processes for treating the solution of hepar with vegetable matter shall either
bo applied to hepar or sulphuret made from sulphat of potash or vitriolated

page_text: tartar, for the purpose of afterwards decomposing the sulphat of soda or Glauber's
salt, or that both the hepar of the sulphat of potash and that of the sulphat
of soda shall be treated in the same mauner with vegetable matters, their
solutions afterwards mixed in the proportions requisite to produce a complete
double decomposition, and the ultimate formation of any two salts, to wit, the
carbonate of soda and the sulphat of potash, which are capable of being casily
separated. The discovery of making use of vegetable matter, and of the com-
bination of the alkali of the hepar with the previously not disengaged acid or
acids of vegetable matter, is perfectly new, and has been made by me; a Patent,
therefore, not only secures to me the use of such vegetable matters with hepars
made of sulphat of soda formed in my processes, and sulphat of potash
recovered and sulphuret of potash formed in my processes, but likewise for
sulphat and sulphuret of soda, and sulphat and sulphuret of potash, however made
or procured. Besides the use of the ligneous and vegetable substances above
mentioned, containing an acid not disengaged, I claim an equal right with
others to the use of the vegetable acids, or acids produced by fermentation, or
of the carbonic acid, for the purpose of separating sulphur from hicpars of potash
and soda, such hepars of potash and soda being made of their respectivo sulphats
got or prepared in the processes now practised by others. But I claim the
exclusive use of the vegetable, or fermented, or carbonic acids for separating
sulphur from the sulphurets or hepars of soda and potash, made from the respective
sulphats of soda and potash, procured in the already described processes. This
Patent is likewise intended to protect me in my Invention or discovery of
disengaging the carbonic acid or fixed air from calcareous earth by the means
of muriatic acid or muriatic acid gas expelled from muriat of soda or muriat of
potash, in the processes for making the respective sulphats already described; of
exclusively applying the carbonic acid thus disengaged to any purpose I
may think proper; and of exclusively making, using, and disposing of the
muriat of limo formed in the process which is thus described. The muriatic
acid or muriatic acid gas expelled from the muriats of soda and potash is to
be convoyed into a vaulted chamber, vessel, or receiver, constructed for the
purpose, containing a sufficient quantity of chalk or mild calcareous carth
and of water; carbonic acid gas will be expelled, which may be collected and
applied to the purposes abovo described, or any other. Exclusive of the uses
already mentioned, and several others not here particularized, the muriatic acid
or muriatic acid gas disengaged in my processes may be converted into oxygenated
muriatic acid, or oxygenated or dephlogisticated muriatic acid gas, by means of
manganese. I claim the exclusive benefit of this, as well as other modes of apply-
ing or using the muriatic acid or muriatic acid gas disengaged in my processes.

page_text: | Process for Decomposing Hepar or Sulphuret of Soda or Potash by Mould
or Soil. Take a quantity of rich black vegetable mould; provide a vat or cistern
having a tap-hole at the bottom; fill it with the mould to within a foot of the top,
putting it in as loosely and keeping it as open as possible. The cistern is then to
be filled with a solution of hepar or sulphuret of potash or of soda, observing, as
the liquor is run in, that it does not run too fast so as to sodden, furrough, or
compress the mould, which is best prevented by causing the ley to run first
into a vessel of a sufficient size sunk to tho level of the mould in the lixiviating
cistern. The cistern should have a cover to exclude the action of air. The
liquid should be kept on the mould, without being run off, until by trial it is
found to have combined with the vegetable acid, and that the sulphur is preci-
pitated or left in the mould. The liquor is then to be boiled down to dryness,
and submitted to calcination; previously to which it may be proper to separate
the phosphoric acid formerly contained in the mould (and with which it, the
alkali, may be combined,) by the means of lime or calcareous earth, and then
to boil down and calcine the clear ley with vegetable matter to give the carbonic
acid. The process answers best when a proportion of carbonate of soda, or of
potash, or mild mineral or vegetable alkali is mixed with the solution of the
bepar or sulphuret before pouring it on the mould, in which case, when the
vegetable acid of the mould combines with the alkali, the carbonic acid is
expelled, and acts in separating the sulphur from the solution of the hepar or