AN IMPROVED MODE OF MANUFACTURING POROUS EARTHENWARE
Year: 1856

page_text: LETTERS PATENT to Alexandre Tolhausen, of No.7, Duke Street, Adelphi,
London, County of Middlesex, Sworn Interpreter at the Imperial Court
of Paris, for the Invention of "AN IMPROVED MODE OF MANUFACTURING
POROUS EARTHENWARE."-A communication from Halvor Halvorson, of
Cambridge, Massachusetts, United States.
Sealed the 5th September 1856, and dated the 26th March 1856.
PROVISIONAL SPECIFICATION left by the said Alexandre Tolhausen at
the Office of the Commissioners of Patents, with his Petition, on the
26th March 1856.
I, ALEXANDRE TOLHAUSEN, of 7, Duke Street, Adelphi, London, County of
Middlesex, Sworn Interpreter at the Imperial Court of Paris, do hereby
declare the nature of the said Invention for "AN IMPROVED MODE OF MANU-
PACTURING POROUS EARTHENWARE, being a communication from Halvor Halvor-
son, of Cambridge, Massachusetts, United States, to be as follows:-
My Invention consists in the use of a volatile salt or substance mixed with
plastic clay or such like substance which is to form the porous ware, the said
volatile salt or substance being driven off in the act of baking the prepared
clay or material, thereby leaving it porous according to the amount of volatile
salt or substances used in the clay, thus forming porous earthenware. Any of
the common processes of mixing, working, or baking earthenware will effect
the object when the volatile salts or substances are used.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Alexandre Tolhausen in the Great Seal Patent Office on the
8th September 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDRE
TOLHAUSEN, of No. 7, Duke St., Adelphi, London, County of Middlesex,
Sworn Interpreter at the Imperial Court of Paris, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-sixth day of March, in the year of our Lord
One thousand eight hundred and fifty-six, in the nineteenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Alexandre Tolhausen, Her special licence that I, the said Alexandre
Tolhausen, my executors, administrators, and assigns, or such others as I,the
said Alexandre Tolhausen, 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 "AN IM-
PROVED MODE OF MANUFACTURING POROUS EARTHENWARE," a communication from
Halvor Halvorson, of Cambridge, Massachusetts, United States, upon
the
condition (amongst others) that I, the said Alexandre Tolhausen, my execu-
tors or administrators, by an instrument in writing under my, or their, or one
of their handsand 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 aud immediately after the date of the said Letters
Patent.
NOW KNOW YE, that I, the said Alexandre Tolhausen, do hereby declare
the nature of the said Invention, and in what manner the same is to bo
performed, to be particularly described and ascertained in and by the following
statement:
The nature of my Invention consists in the use of a volatile salt or sub-
stance mixed with plastic clay, or such like substance, which is to form the
porous ware, the said volatile salt or substance to be driven off in the act of
baking the prepared clay or material, thereby leaving it porous according to
the amount of volatile salt or substances used in the clay, thus forming porous
earthenware.
I take any of the well-known clays or earthy substances employed for
making earthenware, and, while in a plastic state, I mix with it some volatile

page_text: salt or substance, then mould the ware in common moulds, and bake or burn
it in any of the known ways for making unglazed earthenware. In the act
of baking or burning the mass, all the volatile salts or substances are driven
off, leaving the carthy base or ware thus produced of a porous character.
As a general rule, I take one pound of a volatile salt or substance, such as
oxide of mercury, arsenic acid, sulphur, resin, or any similar volatile body,
reduced to fine powder, and mix it intimately with about one pound of plastic
clay, then mould the compound into any form desired by any of the common
methods, then dry and burn it in a common potter's kilu to produce the
degree of hardness requisite for earthenware. By this process a very porous
earthenware is easily and cheaply produced. The porosity of it will just
be in proportion to the amount of volatile substance used in the clay. The
quantities given will make an earthenware of moderate porosity for filters.
The act of burning drives off the volatile substance, leaving the clay of a
strong porous nature. The process is a most simple one for the manufacture
of porous earthenware of different degrees of porosity for various purposes,
such as filters for water, cells for galvanic batteries, etc.
Having thus described the nature and particulars of the said Invention, as
cominunicated to me, I would have it understood that I neither confine myself
to the proportions given, nor to any particular method of mixing, working, or
baking the earthenware described; any of the common processes will effect
the object when volatile salts or substances are used as described; but I claim
the employment of a volatile salt or substance mixed with plastic clay for
manufacturing porous earthenware,as herein described, or in any other manner,
substantially the same.
In witness whereof, I, the said Alexandre Tolhausen, have hereunto set
my hand and scal, this First day of September, in the year of our
Lord One thousand eight hundred and fifty-six.
A. TOLHAUSEN. (L.S.)