A METHOD OF USING CALÇAREOUS EARTHS, THE EARTHS STRONTITES AND BARYTES, ALL OF THEM EITHER IN THEIR CARBONATED OR CALCINED STATES, BUT MORE PRO- PERLY IN THE LATTER STATE, INSTEAD OF ALKALINE SUBSTANCES, FOR NEUTRALIZING THE OXYGENATED MURIATIC ACID USED IN BLEACHING, AND FOR EMPLOYING LIME, STRONTITES, AND BARYTES; THE EARTHS ABOVE MENTIONED, IN THE OTHER PARTS OF THE PROCESS OF BLEACHING, INSTEAD OF POT OR PEARL ASHES, KELP, BARYLLA OR OTHER ALKALINE SUBSTANCES WHATSOEVER
Year: 1798

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
TENNANT, Bleacher, at Darnly, near. Glasgow, send greeting.
WHEREAS His most Excellent Majesty King George the Third did, by
His Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the Twenty-third day of January, in the thirty-eighth year of
His reign, give and grant unto me, the said Charles Tennant, His especial
licence that I, the said Charles Tennant, during the term of years therein
mentioned, should and lawfully might use, exercise, and vend, within
England, Wales, and the Town of Berwick-upon-Tweed, my Invention of
"A METHOD OF USING CALÇAREOUS EARTHS, THE EARTHS STRONTITES AND BARYTES,
ALL OF THEM EITHER IN THEIR CARBONATED OR CALCINED STATES, BUT MORE PRO-
PERLY IN THE LATTER STATE, INSTEAD OF ALKALINE SUBSTANCES, FOR NEUTRALIZING
THE OXYGENATED MURIATIC ACID USED IN BLEACHING, AND FOR EMPLOYING LIME,
STRONTITES, AND BARYTES; THE EARTHS ABOVE MENTIONED, IN THE OTHER PARTS OF
THE PROCESS OF BLEACHING, INSTEAD OF POT OR PEARL ASHES, KELP, BARYLLA, OR
OTHER ALKALINE SUBSTANCES WHATSOEVER;" in which said Letters Patent there
is contained a proviso obliging me, the said Charles Tennant, by an instrument
in writing under my hand and seal, to cause a particular description of the
nature of my said Invention, and in what manner the same is to be performed,
to be inrolled in His Majesty's High Court of Chancery within one calendar
month next and immediately after the date of the said recited Letters Patent,
as in and by the same (relation being thereunto had) may more fully and at
Jarge appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
Charles Tennant, do hereby declare that my said Invention is described in
manner following (that is to say) :-
This Invention consists in a new method of employing calcareous earth,
either uncalcined or in the state of quicklime, for which may be substituted
the earth properly called barites, or that known by the name of strontites, or
the earth magnesia, either in their carbonated or calcined forms, though more
advantageously in the latter. As all these earths are equally applicable in
this Invention it will be sufficient only to specify the way of employing
calcareous earth, as it being the most abundant and easiest to be procured
will therefore be generally preferred. The calcareous earth (in whatever state
of its various varieties it is intended to be used, and which may be employed
almost indiscriminately, altho' the purer the better,) being calcined and reduced
to the state of quicklime, in order to be employed to the greatest advantage,
should be passed through a fine wire sieve, which will be easier accomplished
if the lime has been previously slacked with a little water; next a proportion
of this powdered lime is to be put into the receiver or vessel in use by the
bleacher for preparing his bleaching liquor, and where hitherto a solution of
alkaline salts, such as pot and pearl ash, &c. has been in general used to catch
and retain the oxyginated' muriatic acid gas, my construction or form of which
receiver or-of the aparatus in general I do not condescend upon; that which
is at present in general use answering perfectly well. When the ingredients
put into the retort to procure this gas (whether manganese or common muriatic
acid, or manganese, common salt, and oil of vitriol, or indeed any other
materials capable of yielding it,) begin to give it out, then it is necessary to
keep the liquor in the receiver which contains the quicklime in as constant a
state of agitation as possible, so that the fine particles of the lime be diffused
thoughout the whole of the liquor in the receiver, for on this the success of the
operation depends. I disclaim any right to the discovery of the simple
chemical solution of lime in water, commonly called limewater, for retaining
and fixing the oxyginated muriatic acid gas, it having been long known that lime-
water had some effect in this way; but from the quantity of lime that is soluble
in water being so exceedingly small, only about a seven hundredth part of its
weight, no great benefit was found to be derived from it; whereas by this
process of keeping the lime in a state of mechanical suspension floating
through every part of the fluid in the receiver, it greedily absorbs the oxygi-
nated muriatic acid gas, formingly instantly as it does so a soluble compound,
which possesses in an equal or even superior degree the qualities of the
bleaching liquor usually made by the help of an alkaline lixivium, having the

page_text: very same whitening and detergent powers, as well as that most valuable one
of not discharging dyed colours, but on the contrary preserving and enlivening
them. I cannot take upon me to state the specific quantity of lime necessary
to be put into the receiver for making a given quantity of bleaching liquor,
as that must depend entirely upon the strength and other qualities the liquor is
wanted to possess; however, by use of the following proportions of ingredients
a very excellent and comparatively very cheap liquor will be obtained to what
can be procured by using an alkaline ley strong enough to absorb and retain
the oxyginated muriatic acid gas produceable from the same materials. In
a receiver capable of containing 140 gallons wine measure dissolve 30lbs.
common salt, which appears useful only in giving an additional degree of
specific gravity to the water, and by that means making it easier to keep the
lime to be afterwards added suspended, and for which common salt any other
substance possessing a similar power may be used, and which is itself by no
means essentially necessary. When this salt is dissolved add sixty pounds of
finely powdered quicklime, and into the retort of the apparatus put thirty
pounds manganese mixed. up with thirty pounds common salt, upon which
pour thirty pounds of oil of vitriol, previously deluted with its bulk of water,
and the usual precautions of luting the vessels well, &c., taken. When the gas
begins to appear, the agitation of the lime and water in the receiver must
commence, which should be continued by means of a woodden paddle or rake
of almost any construction, without intermission untill the materials or
wrought off, after employing heat as usual, and will not yield any more
oxyginated muriatic acid gas; then the whole should be allowed to remain
at rest for two or three hours, when the clear liquor in the receiver may be
drawn off for use, and will be found to possess all the qualities before ascribed
to it. Although I have mentioned the above proportions of materials for
making bleaching liquor by my discovery, I think it necessary to declare
these are not the only ones that will be found to answer, as they may be varied
with good effects almost ad infinitum, according to the purpose to which the
liquor it to be applied; also that the spirit of my discovery consists in my
baving found out that the calcareous earth, and that called barites, and that
called strontites, either in the carbonated or calcined states, by being kept in
a state of mechanical suspension in water or other watry fluid, are capable of
uniting with the oxyginated muriatic acid gas, and forming a compound that
can be used with great efficacy in bleaching; and also that these earths thus
mechanically suspended may be used advantageously in the other parts of the
process of bleaching where alkaline salts have been hitherto employed. From
the far greater degree of solubility which the earths barites and strontites

page_text: possess in comparison to lime, I have discovered that a chemical solution of
them may be used with very great effect in neutralizing the oxyginated
muriatic acid, and in the other processes of bleaching, instead of alkaline
substances; and that either the mechanical or chemical suspension of these
earths may be employed with great success, altho the former will be attended
with more than the latter.
In witness whereof; I, the said Charles. Tennant, have hereunto set my
hand and seal, this Thirtieth day of January, in the year of our Lord
One thousand seven hundred and ninety-eight.
CHAS TENNANT. (L.S.)
Sealed and delivered (being first duly
stampt), in the presence of
JAMES STEWART, Witness.
K. FINLEY, Witness.
Kirkman Finley, of the City of Glasgow, North Britain, Merchant, maketh
oath and saith, that he did see Charles Tennant, named in the Deed Poll
hereunto annexed, sign, seal, and as his act and deed in due form of law
deliver, the said Deed Poll in the presence of James Stewart and this
Deponent, and that the name Charles Tennant, appearing to be set and
subscribed at the foot of the said Deed Poll as the party executing the
same, and the names James Stewart and K. Finlay, set and subscribed to the
said Deed Poll as witnesses attesting the due execution of the same, are of the
respective proper handswritings of the said Charles Tennant, James Stewart,
and this Deponent.
Sworn at Glasgow, this Thirtieth day.
of January, 1798,
JAMES MCDOWALL,
K. FINLAY.
Provost of Glasgow.
Inrolled the Third day of February, in the year above written.