IMPROVE- MENTS IN THE MEANS EMPLOYED FOR THE PURIFICATION OF WATER. SP
Year: 1870

page_text: LETTERS PATENT to Gustav Bischof, junior, of Bonn, in the Kingdom of
Prussia, but at present residing at the Craven Hotel, Craven Street,
Strand, in the County of Middlesex, for the Invention of "IMPROVE-
MENTS IN THE MEANS EMPLOYED FOR THE PURIFICATION OF WATER.
PROVISIONAL SPECIFICATION left by the said Gustav Bischof at the
Office of the Commissioners of Patents, with his Petition, on the
19th September 1870.
I, GUSTAV BISCHOF, junior, of Bonn, in the Kingdom of Prussia, but
at present residing at the Craven Hotel, Craven Street, Strand, in the
County of Middlesex, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN THE MEANS EMPLOYED FOR THE PURIFICATION OF WATER,"
to be as follows:-
$6
My Invention consists in using for purifying water the so called
spongy iron" which has been reduced without fusion by any of the
known means instead of employing for this purpose iron that has been
fused. For preparing such spongy iron I take any one of the oxides or

page_text: salts of iron, but preferably the so called purple or spent ore which is
obtained after the copper has been extracted by the wet process from
Spanish or other pyrites.
In order to purify water for drinking and other purposes I fill
one or more tanks provided with a false or perforated bottom with the
finely divided spongy iron, and allow the water (from which any sus-
pended impurity may previously have been separated by filtration
through sand or other material) to filter through the spongy iron.
The spongy iron should always remain covered with water in the
tanks, as otherwise if it is alternately impregnated with water and with
air it is rapidy oxidized, thus losing its power to further purify water.
The rate at which the water may be allowed to filter through the
spongy iron depends upon the degree of impurity, and can easily be
regulated from time to time by testing the water by one of the known
tests after passing through the spongy iron.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Gustav Bischof in the Great Seal Patent Office on
the 14th March 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GUSTAV
BISCHOF, junior, of Bonn, in the Kingdom of Prussia, but at present
residing at the Craven Hotel, Craven Street, Strand, in the County of
Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Nineteenth day of September, in the year
of our Lord One thousand eight hundred and seventy, in the thirty-
fourth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Gustav Bischof, junior, Her special
licence that I, the said Gustav Bischof, junior, my executors, adminis-
trators, and assigns, or such others as I,. the said Gustav Bischof,
junior, 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 "IMPROVE-

page_text: «
MENTS IN THE MEANS EMPLOYED FOR THE PURIFICATION OF WATER," upon the
condition (amongst others) that I, the said Gustav Bischof, junior, 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 Gustav Bischof, junior, 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 Invention consists in using for purifying water the so called
spongy iron" which has been reduced without fusion by any of the
known means instead of employing for this purpose iron that has been
fused. For preparing such spongy iron I take any one of the oxides or
salts of iron, but preferably the so called purple or spent ore, which is
obtained after the copper has has been extracted by the wet process from
Spanish or other pyrites.
In order to purify water for drinking and other purposes I fill one or
more tanks provided with a false or perforated bottom with the finely
divided spongy iron, and allow the water (from which any suspended
impurity may previously have been separated by filtration through sand
or other material) to filter through the spongy iron.
I prefer filtering the water either by descension or by ascension through
a layer of spongy iron about 1 foot thick contained in iron tanks or
filtering beds constructed of brickwork or otherwise. Five or six inches
above the bottom of such tanks or beds there should be a false or perfo-
rated bottom, on the top of which the spongy iron is spread, it having
previously been riddled through a sieve with about five or six holes to
the linear inch.
The spongy iron should always remain covered with water in the tanks,
as otherwise if it is alternately impregnated with water and with air it is
rapidly oxidized, thus losing its power to further purify water.
The rate at which the water may be allowed to filter through the
spongy iron depends upon the degree of impurity, and can easily be
regulated from time to time by testing the water by one of the known

page_text: tests after it has passed through the spongy iron. Under ordinary
circumstances water may pass through the spongy iron at such a rate
that a volume of water equal to the volume of spongy iron in the filtering
apparatus be obtained in five minutes.
Sewage water from which the solid particles have previously been
separated by one of the known means is, according to the rate at which
it passes through spongy iron also so perfectly freed from smell and
organic matter that it might be used with impunity for domestic
*purposes.
The water when passing through the spongy iron dissolves a very
minute trace of protoxide of iron, probably in the state of carbonate.
Through oxidation the protoxide becomes insoluble within about 15
minutes, when it settles down.
The purification of water continues slightly during about 5 hours after
its filtration through spongy iron.
Having thus described the nature of my Invention, and in what manner
the same is to be performed, I wish it to be understood that I am aware
it has already been proposed to employ metallic iron in the form of scrap
iron, iron turnings, iron wire, or sheet iron for the purification of water
by allowing the water to remain in contact with such iron for a certain
length of time in a vessel or reservoir, and I do therefore not claim this
made of proceeding as of my Invention, but what I claim as the Inven-
tion secured to me under the herein-before in part recited Letters Patent
is, the use of "spongy iron," that is to say, iron which has been reduced
from the ore without fusion as a filtering medium for the purification of
water, substantially as herein-before set forth.
In witness whereof, I, the said Gustav Bischof, junior, have
hereunto set my hand and seal, this Tenth day of March,
in the year of our Lord One thousand eight hundred and seventy-
GUSTAV BISCHOF, Ja. (L.S.)