IMPROVEMENTS IN THE PURIFI- PROVISIONAL SPECIFICATION
Year: 1857

page_text: : LETTERS PATENT to Thomas Spencer, of No. 21, Southampton Place, or
as recently designated No. 192, Euston Road, London, Analytical and
Consulting Chemist, for the Invention of "IMPROVEMENTS IN THE PURIFI-
PROVISIONAL SPECIFICATION left by the said Thomas Spencer at
the Office of the Commissioners of Patents, with his Petition; on the
29th December 1857.
I, THOMAS SPENCER, of No. 21, Southampton Place, or as recently desig-
nated No. 192, Euston Road, London, Analytical and Consulting Chemist, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN THE
PURIFICATION OF ILLUMINATING OR LIGHTING GAS," to be as follows:-
For the above purposes of purification I employ, in the first place, the iron ore
which is well known to mineralogists as the "spathose ore." This substance
may be used in lumps or in a granular or powdered state while kept moist.
It may also be used in either of the above states when mingled with sand,
gravel, or other commonly known material, but for which no claim is sought to be
made, except in connection with the ferruginous substances now provisionally
specified.
For the said purposes of purification I employ, in the second place, the
said "spathose ore" after it has been reduced by calcination to a magnetic
though not to a metallic state. This magnetic substance may be used in the
same manner as the raw ore; that is to say, whilst moist in lumps or granu-
lated, and also along with any other commonly known material.

page_text: For the said purposes of purification I employ, in the third place, any ore,
sand, or other substance which may contain proportions of ferruginous substance
in a magnetic state, or which may be reduced by calcination, or otherwise
brought to the same state.
For the above purposes of purification no ferruginous substances are intended
to be claimed other than the "spathose. ore," and those which are at the same
time non-metallic, and are attracted by the magnet.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Thomas Spencer in the Great Seal Patent Office on the
29th June 1858.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
SPENCER, Analytical and Consulting Chemist, of No. 21, Southampton Place,
or as recently designated, Number 192, Euston Road, London, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-ninth day of December, in the year of our
Lord One thousand eight hundred and fifty-seven, in the twenty-first year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Thomas Spencer Her special licence that I, the said Thomas
Spencer, my executors, administrators, and assigns, or such others as I,
the said Thomas Spencer, my executors, administrators, and assigns, should
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-
MENTS IN THE PURIFICATION OF ILLUMINATING OR LIGHTING GAS," upon the con-
dition (amongst others), that I, the said Thomas Spencer, 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 per-
formed, 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 Thomas Spencer, do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:
.11

page_text: The said Invention consists in a method of effecting the purification of
illuminating gas from gaseous sulphurous compounds, by materials not hitherto
applied to that purpose..
The mode by which the same is effected will be best understood by explaining
the practical details which appertain to each clause of the Provisional Specifi-
cation lodged by me in reference to the present Patent.
.
i
It is there stated, that to effect the said purification I employ, in the first
place, the iron ore known to mineralogists as the "spathose ore," which
substance may be used in lumps or in a granular state, and while moist. This
ore is found in several parts of this country and on the continent of Europe,
and is a white cream-colored substance, known to chemists as a carbonate of
the protoxide of iron. I have discovered that it possesses the property of
absorbing sulphur from ordinary carburetted hydrogen or illuminating gas.
To effect this object it is only necessary to place the ore in any of the well
known forms of purifying apparatus, and then cause the gas requiring
purification to pass through the same. The operation will be best understood,
however, by those practically engaged in the manufacture of gas, when I state
that the form of apparatus I prefer is in all respects analogous to that used
in the process of purification by means of dried lime. The ore itself may be
placed in the purifier in lumps, or granular, or in powder, but I prefer to use
it in a state of granulation, analogous to that of coarse gunpowder. During
the process of purification it is necessary that the ore should be kept slightly
moist, which applies equally to the other substances named in this Patent.
When the sulphur has been absorbed from the gas, the color of the ore
in the purifyer will have changed from cream white, to black, the intensity of
the latter denoting the amount of sulphur absorbed. As soon as, the ore
has passed into this state, it is to be removed, and a fresh charge substituted..
In the second clause of my Provisional Specification I have stated that the
black magnetic substance which results from the calcination of the spathose
ore, will also effect the purification of illuminating gas, though the same
substance will be produced on roasting the ore in the open fire, yet the oper-
ation is best and most economically performed at a very low red heat in
ordinary gas retorts. In performing the process of purification by these
means with this substance, it is only necessary that it should be placed in
the well-known purifying apparatus already referred to, and the gas be made
to pass over or through the same in the ordinary manner practised in the
process of purification by dry lime, the oxide being kept slightly moist during
the operation.
The third.clause of my Provisional Specification states that any ore or sand

page_text: or substance containing ferruginous matter in a magnetic state, or any
substance not naturally so, but which by treatment may be reduced to this
state, is also available for the said purifying purposes. The substances there
referred to are magnetic ores and ferruginous sands, and also a magnetic
substance obtained by calcining the well-known hematite or peroxide ores
along with carbonaceous matter.
many of
With regard to the natural magnetic ores, I have discovered that
them are capable of absorbing the sulphur from impure gas, though as in the
case of the other ores named, the operation is more effectually performed after
they have been subjected to a process of roasting or calcination. To render
non-magnetic ferruginous sands and hematite ores magnetic, and thereby
available for these purposes; it is necessary to calcine them in retorts along
with coke, charcoal, anthracite, or in fact any carbonaceous matter, care being
taken during the operation not to apply more than a low red heat to prevent
the reduction of the ore. It may be necessary to explain that in the course of
this calcining process, a proportion of the oxygen belonging to the ore combines
with the carbonaceous matter, and is given off as carbonic oxide. When this
gas ceases to be formed, which is easily ascertained by having a small 'stop-
cock in front of the retort, the process of converting the peroxide into the
magnetic state is complete, and on cooling the converted ore may be removed
for use in the purifyer. In practice I find that from ten to twelve per cent. of
carbonaceous matter mixed with the raw ore is sufficient to effect its reduction
to this state. I may mention that a larger portion of carbonaceous matter
may be used in this process, as any excess may be made available for a
succeeding operation. When the óre exists in large lumps, I prefer that it
should be crushed or granulated previous to its being placed in the retorts.
In the purifying operation any of the substances I have named may be used
alone, or in combination with any other substance that 'may be found con-
venient. For example, should it be required to use the spathose ore, or
magnetic oxide in a state of fine powder; in order that the unpure gas should
freely permeate beneath the surface of the mass, it may be necessary to mix
it with a coarser material, such as sand or sawdust. Moreover, when the
spathose ore is used in the raw state, I prefer to mix it with a small pro-
portion of caustic lime, to absorb any carbonic acid liberated from the ore by
reason of its combination with the sulphur of the unpure gas. It is now
important to state, that when any of the above ferruginous substances become
saturated with sulphur in the purifying operation, each of them may be made
to repeat the process without limitation. To effect this desirable object with
economy, the spent substance is to be placed in a retort and subjected to heat

page_text: sufficient to distil off the sulphur, which may be collected in a molten state
from the retort and used as ordinary sulphur. At the close of this operation
the ferruginous substance on cooling may be placed in the purifyer, and used
as before. Moreover, when again saturated the sulphur may be again dis-
tilled off any number of times. In this revivifying operation I prefer to use
earthenware retorts, though those of iron that have become coated with carbon
answer the purpose very well. I wish it to be understood that no claim is intended
to be advanced by me for this mode of distilling sulphur from any refuse or
spent purifying media already known. On the other hand the mode is claimed
by me when applied to the renovation of the spathose or magnetic ores or
magnetic oxides, however obtained, the application of which substances for.
the purification of illuminating gas is here, to the best of my knowledge, made
known for the first time.
I am already aware that a ferruginous oxide prepared from a salt of iron is
used by some in the purification of gas. This substance has been improperly
designated or described as a "carbonate of iron," meaning thereby a carbonate
of the preoxide of iron, but which body has no practical existence. On
its formation the substance intended in reality a hydrated peroxide of iron,
but which loses its constitutional water on the application of intense heat,
and is then a peroxide only, and which is characterised as not being attracted
by the magnet.
Having now discribed the nature of my said Invention, I desire it to
be understood that I make no claim for the method or manner of performing
the process of purification; what I do claim is this application of the white
spathose ore to the purification of illuminating gas. I also claim the appli-
cation of the magnetic oxide of iron in either its native or artificial state, to
the same purposes. I may add in conclusion, that where I am enabled to
procure the said oxide in its natural state, I prefer to obtain it directly from
the ores I have named, by treating them in the manner herein described.
In witness whereof, I, the said Thomas Spencer, have hereunto set my
hand and seal, this Twenty-ninth day of June, in the year of our
Lord One thousand eight hundred and fifty-eight.
THOMAS SPENCER.
(L.S.).