IMPROVEMENTS IN THE TREATMENT OF SULPHATE OF ALUMINA
Year: 1864

page_text: LETTERS PATENT to Alexander Angus Croll, of Coleman Street, in
the City of London, Civil Engineer, for the Invention of "IMPROVEMENTS
IN THE TREATMENT OF SULPHATE OF ALUMINA."
Sealed the 24th March 1865, and dated the 30th September 1864.
PROVISIONAL SPECIFICATION left by the said- Alexander Angus Croll
at the Office of the Commissioners of Patents, with his Petition, on the
30th September 1864.
I, ALEXANDER ANGUS CROLL, of Coleman Street, in the City of London, Civil
Engineer, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS, IN THE TREATMENT OF SULPHATE OF ALUMINA," to be as follows:-
lime
My improvements relate to combining caustic lime or carbonate
with sulphate of alumina for the purpose of neutralizing free acid resulting,
from its manufacture.
For this purpose I add the caustic lime or carbonate of lime to the sulphate
of alumina whilst the sulphate of alumina is in a heated state and in pro-
portions dependent upon the condition of neutrality desired to be obtained..

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Alexander Angus Croll in the Great Seal Patent Office
on the 30th March 1865.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDER
ANGUS CROLL, of Coleman Street, in the City of London, Civil Engineer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirtieth day of September, in the year of our Lord
One thousand eight hundred and sixty-four, in the twenty-eighth year of Her
reign, did, for Herself, Her, heirs and successors, give and grant unto me,
the said Alexander Angus Croll, Her special licence that I, the said Alexander
Angus Croll, my executors, administrators, and assigns, or such others as
I, the said Alexander Angus Croll, my executors, administrators, and 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 TREATMENT OF SULPHATE OF ALUMINA," upon the con-
dition (amongst others) that I, the said Alexander Angus Croll, my
executors or administrators, by an instrument in writing under my, or
their, or one of their hands and seals, 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 immediately after the date of the
said Letters Patent:
NOW KNOW. YE, that I, the said Alexander Angus, Croll, do hereby
declare the nature of the said Invention, and in what manner, the same is, to, be
performed, to be particularly described and ascertained in and by the following
statement thereof, that is to say:-
My improvements relate to combining caustic lime or carbonate of lime
with sulphate of alumina for the purpose of neutralizing free acid' resulting
from its manufacture.
For this purpose I add the caustic lime or carbonate of lime to the sulphate
of alumina whilst the sulphate of alumina is in a heated state or before it has
been allowed to cool down to about 200° Fahrenheit, or much below that
temperature, and I employ the carbonate of lime in a state of fine powder, such
as ground whiting, and in the proportion of about 3 per cent. thereof to the
quantity of sulphate of alumina operated upon and which has arrived at a

page_text: sufficiently concentrated state to be capable of forming cake or becoming
stiff or solid when cool. These proportions will, however, be dependent upon
the condition of neutrality desired to be obtained or the amount of uncombined
acid required to be neutralized.
In witness whereof, I, the said Alexander Angus Croll, have hereunto
set my hand and seal, this Thirtieth day of March, in the year of our
Lord One thousand eight hundred and sixty-five.
A. ANGUS CROLL. (L.s.)