IMPROVEMENTS IN THE MANUFACTURE OF SULPHATE OF SODA
Year: 1863

page_text: LETTERS PATENT to Thomas Richardson, of the Town and County of
Newcastle-upon-Tyne, Chemist, and James Cochran Stevenson, of the
Jarrow Chemical Works, in the County of Durham, Chenical Manu-
facturer, for the Invention of "IMPROVEMENTS IN THE MANUFACTURE OF
SULPHATE OF SODA."
Sealed the 16th October 1863, and dated the 23rd April 1863.
PROVISIONAL SPECIFICATION left by the said Thomas Richardson and
James Cochran Stevenson at the Office of the Commissioners of Patents,
with their Petition, on the 23rd April 1863.
We, THOMAS RICHARDSON, of the Town and County of Newcastle-upon-
Tyne, Chemist, and JAMES COCHRAN STEVENSON, of the Jarrow Chemical
Works, in the County of Durbam, Chemical Manufacturer, do hereby declare
the nature of the said Invention for "IMPROVEMENTS IN THE MANUFACTURE OF
SULPHATE OF SODA," to be as follows:-
This Invention has for its object improvements in the manufacture or pro-
duction of sulphate of soda, and consists in submitting common or rock salt to
an elevated temperature, and employing the same whilst in a heated state, with
sulphuric acid, for the manufacture of sulphate of soda. The temperature of
the salt must not exceed the boiling point of the sulphuric acid employed.
When rock salt is used it must be ground as well as heated.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Thomas Richardson and James Cochran Stevenson in the
Great Seal Patent Office on the 23rd October 1863.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, THOMAS
RICHARDSON, of the Town and County of Newcastle-upon-Tyne, Chemist,
and JAMES COCHRAN STEVENSON, of the Jarrow Chemical Works, in the
County of Durham, Chemical Manufacturer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-third day of April, in the year of our Lord
One thousand eight hundred and sixty-three, in the twenty-sixth year of
Her reign, did, for Herself, er heirs and successors, give and grant unto us,
the said Thomas Richardson and James Cochran Stevenson, Her special
license that we, the said Thomas Richardson and James Cochran Stevenson,
our executors, administrators, and assigns, or such others as we, the said
Thomas Richardson and James Cochran Stevenson, our executors, administra-
tors, or assigns, should at any time agree with, and no others, from time to
time and at all times thereafter during the term therein expressed, should and
lawfully might make, use, exercise, and vend, within the United Kingdom of
Great Britain and Ireland, the Channel Islands, and Isle of Man, an Invention
for "IMPROVEMENTS IN THE MANUFACTURE OF SULPHATE OF SODA," upon the con-
dition (amongst others) that we, the said Thomas Richardson and James
Cochran Stevenson, our executors or administrators, by an instrument in writing
under our bands and seals, or under the hand and scal of one of us, should
particularly describe and ascertain the nature of the said Invention, and in
what manner the same was to be performed, and cause the same to be filed
in the Great Seal Patent Office within six calendar months next and imme-
diately after the date of the said Letters Patent.
NOW KNOW YE, that we, the said Thomas Richardson and James
Cochran Stevenson, do hereby declare the nature of our said Invention, and
in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement, that is to say:-
Our said Invention has for its object improvements in the manufacture or
production of sulphate of soda,
In the manufacture of sulphate of soda in alkali works, common salt and
sulphuric acid are mixed together in a decomposing pan, but the salt is used
at the ordinary temperature, and the sulphuric acid is generally heated before
being mixed with the salt.
Our Invention consists in heating the salt by any convenient method before

page_text: mixing it with the acid. In order to prevent evaporation of the sulphuric
acid, the temperature of the heated salt must not exceed the boiling point of
the sulphuric acid employed. If sulphuric acid be used cold, a greater heat
may be given to the salt, but the temperature of the mixture should never
exceed the boiling point of the acid. When using heated acid the salt may
be employed at a temperature of 250° Fabrenheit, and when the acid is used
cold the salt may be heated to 400° Fahrenheit. The salt may be heated in
a separate furnace, which has the advantage of enabling it to be weighed in a
dried state, or the salt may be dried within the furnace on a bed or hearth
adjoining the pan, or over the furnace by the waste heat passing through the
arch or cover of the pan or surface. When rock salt is used, it must be
ground sufficiently fine to pass through a sieve of parallel wires placed
one-twentieth of an inch apart, and we prefer to heat it after it is ground.
Having now described and particularly ascertained the nature of our said
Invention, and the manner in which the same is or may be used or carried
into effect, we would observe in conclusion that what we consider to be novel
and original, and therefore claim as the Invention secured to us by the herein-
before in part recited Letters Patent, is, the heating of salt used in the manu-
facture of sulphate of soda previous to its being mixed with sulphuric acid in
the decomposing furnace.
In witness whereof, I, the said James Cochran Stevenson, on behalf of
myself and the said Thomas Richardson, have hereunto set my hand
and seal, this Twenty-first day of October, in the year of our Lord
One thousand eight hundred and sixty-three.
JAMES C. STEVENSON. (L.S.)