IMPROVEMENTS IN THE MANUFACTURE OF ALKALI AND CHLORINE, AND IN THE APPLICATION OF THE PRODUCTS RESULTING THEREFROM
Year: 1847

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
TENNANT DUNLOP, of Glasgow, in the County of Lanark, Manufacturer,
send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Sixteenth day of
March, One thousand eight hundred and forty-seven, in the tenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Charles Tennant Dunlop, my exors, admors, and assigns, Her especial
licence, full power, sole privilege and authority, that I, the said Charles
Tennant Dunlop, my exors, admors, and assigns, or such others as I, the
said Charles Tennant Dunlop, my exors, admors, 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, my Invention of "IMPROVEMENTS IN THE MANUFACTURE OF ALKALI AND
CHLORINE, AND IN THE APPLICATION OF THE PRODUCTS RESULTING THEREFROM;" in
which said Letters Patent is contained a proviso, that I, the said Charles
said
Tennant Dunlop, shall cause a particular description of 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, to be inrolled in Her said Majesty's
High Court of Chancery within six calendar months next and immediately

page_text: after the date of the said in part 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 Tennant Dunlop, do hereby declare that the nature of my said
Invention, and the manner in which the same is to be performed, are fully
described and ascertained in and by the following statement thereof, that is
to say:-
My Invention consists in an improved method of producing chlorine fit for
manufacturing purposes by effecting mutual decompositions between the
following substances:-muriate of soda or any other muriate, nitrate of soda
or any other nitrate, muriatic acid, nitric acid. The assistance of sulphuric
acid is in some cases required. I generally prefer employing it, in order to
obtain for residuum sulphate of soda suitable for the manufacture of soda, &c.
The above substances may be employed either altogether or only two of
them; as, for instance, a nitrate with a muriate, (in which case of course
sulphuric acid must be employed,) or a muriate with nitric acid, or a nitrate
with muriatic acid; or muriatic and nitric acids may be used together. For
the latter cases sulphuric acid is employed; according to the results wished to
be obtained.
I do not confine myself to any proportion, but the process I usually adopt
1
is to bring together common salt, nitrate of soda, or nitric acid and sulphuric
acid in suitable proportions.
On the application of heat, chlorine, an oxyde of azote, and muriatic acid,
are evolved. These gases are then passed through a suitable condenser charged
with sulphuric acid of a strength sufficient to absorb the oxyde of azote. The
chlorine and muriatic acid are then separated by means of water.
The second part of my Invention, which relates to the application of the
product resulting from the above process, consists in the production of nitric
acid from the sulphuric acid charged with oxyde of azote, and which is truc
nitrous sulphuric acid, and is effected by the aid of atmospheric air, steam, and
water. The process I usually follow is to introduce the nitrous sulphuric acid
into a suitable vessel, when by the addition of water and heat the oxyde of
azote is disengaged. This latter is caused to traverse a suitable condenser
along with a sufficient quantity of air and steam, or water, and is by this
means all transformed into nitric acid, which can be used again in the manu-
facture of chlorine and again recovered in the manner above described,
and so on. Instead of treating the nitrous sulphuric acid in this manner, I
sometimes evolve the oxyde of azote, and receive it in a suitable chamber,

page_text: into which a current of sulphuretted hydrogen is streaming at the same time.
By this means sulphate of ammonia is obtained and sulphur deposited.
What I claim is, the manufacture of chlorine from the materials above
mentioned in the manner detailed. The process employed for separating the
gaseous products so as to obtain the chlorine in a sufficiently pure state for
manufacturing purposes; and the two processes described for utilizing the
products resulting from the manufacture of chlorine.
In witness whereof, I, the said Charles Tennant Dunlop, have hereunto
set my hand and seal, this Eleventh day of September, in the year
of our Lord One thousand eight hundred and forty-seven
CHARLES TENNANT (L.S.) DUNLOP.
AND BE IT REMEMBERED, that on the Eleventh day of September, in
the year of our Lord 1847, the aforesaid Charles Tennant Dunlop came before
our said Lady the Queen in Her Chancery, and acknowledged the Specification
aforesaid, and all and every thing therein contained and specified, in form
above written. And also the Specification aforesaid was stamped according to
the tenor of the Statute made for that purpose.
Enrolled the Sixteenth day of September, in the year of our Lord One
thousand eight hundred and forty-seven.