A METHOD OR METHODS OF PREPARING AND OBTAINING ALUM, OR THE SALT CALLED SULPHAT OR VITRIAL OF ARGIL, AND THAT IN THE SAME PROCESS, OR IN PROCESSES CONNECTED THEREWITH, I HAD PREPARED AND OBTAINED CERTAIN OTHER SALTS, SALINE MATTERS, AND SUBSTANCES, WHICH WOULD BE OF GREAT PUBLIC UTILITY
Year: 1794

page_text: THE EARL OF DUNDONALD'S SPECIFICATION.
TO ALL TO WHOM THESE PRESENTS SHALL COME, ARCHIBALD Earl
of DONDONALD, 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 experice, found out and discovered
"A METHOD OR METHODS OF PREPARING AND OBTAINING ALUM, OR THE SALT CALLED
SULPHAT OR VITRIAL OF ARGIL, AND THAT IN THE SAME PROCESS, OR IN PROCESSES
CONNECTED THEREWITH, I HAD PREPARED AND OBTAINED CERTAIN OTHER SALTS,
SALINE MATTERS, AND SUBSTANCES, WHICH WOULD BE OF GREAT PUBLIC UTILITY;" 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 Fourth day of October, in
the thirty-fourth 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, administrators,
and assigns; His special licence, full power, sole privilege and authority, that

page_text: I, the said Archibald Earl of Dundonald, my executors, administrators, and
assigns, and every of us, by myself and themselves, or by mine and their
deputy or deputies, servants or agents, or such others as I, the said Archibald
Earl of Dundonald, my executors, administrators, or assigns, should at any time
agree with, and on 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 Majesty's said
Kingdom of Great Britain called England, His Dominion of Wales, and
Town of Berwick-upon-Tweed, and Colonics and Plantations abroad, in such
manner as to me, the said Archibald Earl of Dundonald, my executors, ad-
ministrators, and assigns, or any of us, should in our discretion seem meet,
and that I, the said Archibald Earl of Dundonald, my executors, adiñors, 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 terin of years
therein mentioned; to have, hold, exercise, and enjoy the said licence, powers,
priviledges, and advantages therein-before granted or mentioned to be granted
'unto me, the said Archibald Earl of Dundonald, my executors, adminis-
trators, 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 provisoc 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 an instrument in writing under my hand and seal, and
cause the same to be inrolled in His Majesty's High Court of Chancery within
one calendar month next and immediately after the date of the said Letters
Patent, that then the said Letters, and all liberties and advantages what-
soever 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 describo and ascertain the nature
of my said Invention, and declare that the alum, or the salt called sulphat or
vitrial of argil, and the other salts, saline matters, and substances, are made
as follows (that is to say) :—
My first process consits in lixiviating, washing, or dissolving the saline
matters contained in alluminous, vitriolic, or pyrituous rock, shyst, or substances

page_text: with sea water, or with solutions of sea or rock salt, chemically called muriat
of soda, or with solutions of kelp, sandiver, soaper's ashes, salts, or leys, or
with the solution of any saline substance containing muriat of soda. The
sea water, or the solution of any of the above-mentioned salts, may either be
applied to lixiviate or dissolve the saline matters contained in alluminous,
vitrolic, or pyrituous shyst or materials, when these materials had been calcined
by fire, or when they had been decomposed by exposure to air, as may best
suit the nature of the materials. This process may likewise be performed by
mixing any saline substance containing sea salt or murint of soda with allu-
minous, vitriolic, or pyrituous materials, and by afterwards dissolving the saline
matters thus mixed together by the addition of water. Or I perform this
process in another way, by adding sea salt or muriat of soda, or salts containing
muriat of soda or their solutions, to alluminous or vitriolic salts, or to alluminous
or vitriolic, or pyrituous liquors or solutions. It is proper here to mention that
in the common process of allum making, salts coutaining muriat of soda, or
their solutions are made use of, and mixed with the alluminous liquor either
in the process of boiling or in the coolers or settlers. The salts used by the
allum makers are kelp, soaper's ashes, or salts and sandiver, or any alkaline
salt to be had at a cheap rate. These alkaline salts are used for the purpose
of neutralizing the superabundant proportion of vitriolic or sulphuric acid
contained in the alluminous liquour, and to promote thereby the proper crys-
tallization of the allum, and with that view only. But in my Affidavit and
Petition, certain other salts, saline matters, and substances are stated to be
made either in the process for allum making, or in processes connected there-
with; therefore, whoever shall make use of sea salt, or muriat of soda, or salts
or their solutions containing muriat of soda, and shall make or cause to bo
made sundry salts, saline matters, and substances, in the manner described in
this Specification, will be deemed to have infringed on this Patent. These
salts, saline matters, and substances are Glauber salts, spirit of sea salt, or
muriatic acid and sal ammoniac.
-.
Having stated the different methods of mixing sea salt, or muriat of soda,
or solutions of salts containing muriat of soda, with alluminous, vitriolic, or
pyrituous saline matters or materials, or with their solutions, I now proceed to
describe the other processes. The liquor resulting from the mixtures before
described is to be boiled or prepared to the weight or concentration necessary for
the crystallisation of allum, and treated with or without alkaline salts, as shal!
be found necessary. The slam, mother liquor, washings, or tun liquor, as they
are called at the allum works, procceding from the last-mentioned process, or
from any process in the preparation of allum, are to be mixed with such pro-

page_text: portion of sea salt or muriat of soda, or salts or their solutions containing muriat
of soda, as shall be requisito. To this liquor or saline matter is to be added a
due proportion of allum, shyst, clay, or argillacious matter. The shyst or
clay which is found to answer best is what contains a large proportion of the
earth of iron. The materials are then to be dryed, ground to a powder, and
submitted to the action of heat in a reverberatory or other furnace, pot, or
crucible, until the muriatic acid is expelled. For the more effectual expulsion
of the muriatic acid, two dillèrent calcinations or applications of heat inay he
used, moistening the materials with water between the different calcinations.
The materials are then to be lixiviated or washed with water. The lixivium,
when the process has been properly conducted, will consist of a salution of
Glauber salt, which may either by chrystalled, boiled, and evaporated to dry-
ness, or keept in a liquid state, as the uses for these different preparations shall
require. The residuum, after lixiviation, consists of an argillaceous ochry
matter, which, when there is much iron in the alluminous or vitriolic shyst or
argillaceous matter used, or a large proportion of green vitrial or sulphat of
iron or muriat of iron in the saline liquor or materials mixed with the before-
mentioned shyst or clay, may, by washing, levigation, and drying, bo rendered
fit to be used as a rigment. The marine or muriatic acid expelled by heat
from the materials, ns has been already mentioned, may, when it is thought
proper to collect it, be collected by using the methods and vessells used by
chemists; and sul ammoniac may be formed by combining muriatic acid or
muriatic and gass with valatilo alkali or valatile alkaline gass, procured from
coal tar water, urine, soot, bones, or other materials.
According to the above Specification, I lay claim to the following Inventions
or Discoveries, and to the exclusive exercise of them during the Patent :-To
lixiviating or washing alluminous vitrialic or pyrituous shyst or materials with
sea water, or with salutions of salts containing muriat of soda; or to mixing
salts containing sea salts or muriat of soda in any way with alluminous, vitrialic,
or pyrituous substances, for the purpose of making, as has been described,
allum, Glauber salt, muriatic acid, or sal ammoniac; or to the mixing of sea
salt or muriat of soda, or any salt containing muriat of soda, or their
solutions, with solutions of alluminous, vitriolic, or pyrituous materials, for the
purpose of making Glauber salts, muriatic acid, and sal ammoniac.
I likowiso lay claim, under the Patent, to the exclusive priviledge of mixing
sea salt, or salts containing muriat of soda, or their solutions, with allum, slam,
mother liquor, washings of allum, or tun liquor, for the purpose of making
Glauber salt, muriatic acid, and sal ammoniac.
By the words alluminous, vitriolic, or pyrituous rock, shyst, or substances, is

page_text: meant and is to be understood, such substances as, by calcination or exposure
to air or otherwise, contain, yield, or produce allum, or the vitrial or sulphat of
argil, green vitrial, or the vitrial or sulphat of iron and Epsom salt, or the
vitrial or sulphat of magnesia. These salts are often found blended or mixed
together, particularly in allum, shyst, shale, or their solutions. At the same
time, any one of these salts may be decomposed singly and by itself, and by
following the directions already given, be made to produce, with muriat of
soda or salts containg muriat of soda, Glauber salt, or sulphat of soda. For
the manufacture of this article, the Patent, of which this is the Specification,
has been applied for and taken out, included under the those words in the
Patent, Certain other Salts, Saline Matters, and Substances," and ac-
cordingly, with the intervention or aid of argillacious matter or feruginous
argillaceous matter, Glauber salt is produced by mixing sulphat of allum,
sulphat of iron, or sulphat of magnesia (from whatever materials they are
got or procured) with muriat of soda, or salts containing muriat of soda, and
then by applying to the materials a due degree of heat.
It is proper likewise to mention, that I decompose muriat of soda in a great
measure by sulphat of magnesia, without the intervention or aid of argillacious
This process, discovered by me, I likewise reckon to be included in
my Patent.
In witness whereof, I, the said Archibald Earl of Dundonald, have
hereunto sett my hand and seal, the Fourth day of November, in the
year of our Lord One thousand seven hundred and ninety-four, and in
the thirty-fifth year of the reign of our Sovereign Lord George the
Third, of Great Britain, France, and Ireland King, Defender of the
Faith and so forth.