IMPROVEMENTS IN THE MANUFACTURE OF GAS FOR ILLUMINATION AND OTHER PURPOSES TO WHICH COAL GAS IS APPLICABLE; IN PREPARING MATERIALS TO BE EMPLOYED IN SUCH MANUFACTURE, AND IN APPARATUS FOR MANUFACTURING AND USING GAS; ALSO
Year: 1850

page_text: TO ALL TO WHOM THESE. PRESENTS SHALL COME, I, RICHARD
LAMING, of Charlton, in the County of Kent, Chemist, and FREDERICK JOHN
EVANS, of Westminster, in the County of Middlesex, Gas Engineer, send
greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent, under the Great Seal of Great Britain, bearing date
at Westminster, the Twenty-third day. of April, in the thirteenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto us,
the said Richard Laming and Frederick John Evans, Her especial licence,
full power, sole privilege and authority, that we, the said Richard Laming
and Frederick John Evans, our exors, adññiors, and assigns, and such others
as we, the said Richard Laming and Frederick John Evans, our exors, adñors,
or assigns, should at any time agree with, and no others, from time to time
and at all times during the term of years therein mentioned, should and law-
fully might make, use, exercise, and vend, within England, Wales, and the Town
of Berwick-upon-Tweed, our Invention of "IMPROVEMENTS IN THE MANUFACTURE
OF GAS FOR ILLUMINATION AND OTHER PURPOSES TO WHICH COAL GAS IS APPLICABLE;
IN PREPARING MATERIALS TO BE EMPLOYED IN SUCH MANUFACTURE, AND IN APPARATUS
FOR MANUFACTURING AND USING GAS; ALSO IMPROVEMENTS IN TREATING CERTAIN
PRODUCTS RESULTING FROM THE DISTILLATION OF COAL; PARTS OF WHICH ABOVE-MEN-
TIONED IMPROVEMENTS ARE APPLICABLE TO OTHER SIMILAR PURPOSES;" in which said
Letters Patent is contained a proviso obliging us, the said Richard Laming:and
Frederick John Evans, by an instrument in writing under our hands and seals,
particularly to describe and ascertain the nature of our said Invention, and in

page_text: what manner the same is to be performed, and to cause the same to be enrolled
in Her Majesty's High Court of Chancery within six calendar months next
and immediately after the date of the said in part recited Letters Patent, as
in and by the same, reference being thereunto had, will more fully and at large
appear.
NOW KNOW YE, that in compliance with the said proviso, we, the said
Richard Laming and Frederick John Evans, do hereby declare that the
nature of our said Invention, and the manner in which the same is to be
performed, is particularly described and ascertained in and by the following
description thereof, reference being had to the Drawings hereunto annexed,
and to the letters and figures marked thereon (that is to say) :-
:-
One part of our Invention is an improvement in retorts for making gas and
other purposes, and in melting-pots, crucibles, muffles, stoves, fire bricks, and
lumps and other articles of clay required to stand the action of fire without
cracking. The improvement consists in mixing with the fire clay which is to
enter into the composition of any of the aforesaid articles about 0.25 per cent.
of its weight of asbestos or fibrous silicate of magnesia; the vessels are then to
be constructed and burned in the manner understood by artisans engaged in
the various branches of the art.. We do not confine ourselves to any particular
forms of the articles, and each may be made of one or more pieces as at pre-
sent; the proportion of the silicate of magnesia may be varied to meet the
exigencies of particular cases, its introduction being for the purpose of giving
greater tenacity to the materials used, and thus diminish their aptitude to
become cracked under the influence of change of temperature.
We claim under this head of our Invention the introduction of asbestos, or
fibrous silicate of magnesia, among the materials used for making articles of
clay intended to be submitted to a great heat, and the use of all such articles
made with asbestos, or fibrous silicate of magnesia, in their composition.
Another part of our Invention is a particular arrangement of apparatus for
making gas from oil, tar, melted pitch, resin, fat, or other analogous material,
in conjunction or not with water. This arrangement of apparatus will be
understood by referring to the accompanying Drawing, in which Fig. 1
represents it in longitudinal vertical section, Fig. 2 in transverse vertical
section, and Fig. 3 in elevation. The same letters refer to like parts in
all the Figures. Fig. 1 is a retort in iron or clay, composed of two chambers,
A and B, and which are closed by three manhole doors C, C, C, two of them
in front, and one larger at the back, all three projecting beyond the brick-
work setting. D, D, is a funnel of large diameter, closed by a cover E,
either dropping into an hydraulic joint, filled with metal, fusible at the tem<

page_text: perature to which it is exposed, or by screwing in any ordinary manner of
manhole doors. The cover E is fitted with a double syphon F, governed by a
stopcock. G is the eduction pipe conducting to the hydraulic main. To
use this apparatus, previously raised to the usual temperature, we charge the
chamber B with coke, heaping it somewhat at the part marked B, Fig. 1,
and allowing some pieces to fall over against the large manhole door at
the back. We charge the chamber A either with coal or coke. We intro-
duce a stream, regulated by the stopcock, of oil, tar, melted pitch, resin, fat,
or other analogous matter, in conjunction with water or not, by the double
syphon F, and the large funnel D, D, causing it to fall upon the red-hot
coke at B, and to pass thence, partly as gas and partly as liquid, through the
upper chamber to the back of the lower one, along which it next passes,
chiefly in the state of gas, to escape, mixed with the gaseous products of the
chamber A, by the eduction pipe G, into the hydraulic main. When we charge
the lower chamber of this apparatus with coal we prefer not to let in the
liquid which enters by the double syphon until the coal has had time to give
off great part of its richer gas, and to become heated throughout, but when we
use coke, in both chambers we let in the liquid from the commencement and
without intermission until the passages of the gas need to be opened and cleaned
out. The operation of cleaning, which is so frequent and difficult with other
forms of apparatus as to prevent their successful employment, is with our
Invention both easy and comparatively unfrequent.
We do not claim the making of gas from tar or any other form of hydro-
carbon, or water, by means of red-hot coke, or the combining of any materials
for affording gas. What we claim under this head of our Invention is, the com-
bination and arrangement of apparatus, particularly of the large funnel marked
D, D, with the double chambers and back and front manholes doors for
making gas by the decomposition of any suitable hydrocarbon or water, by
bringing it in a fluid state into contact with red-hot coke, or other suitable
material.
Another part of our Invention consists in elongating the eduction pipes of
retorts used for making gas for illumination into their interior, and arranging
them in lines near their axes. We leave the farther ends of these pipes open,
and support them on a bearer. Holes should be made along the pipes only in
sufficient number to permit of the free escape of the gas as it is generated; but
what is better is, to leave a longitudinal slit at the under side of the horizontal
pipe from its further end to near its ascending portion, as this arrangement
admits of the passage being cleared out by a proper tool in the event of its
becoming choked. The improvement is applicable to retorts of the ordinary

page_text: forms and of any material, but we find it more easy to charge them where this
Invention is adopted, when they are made wide enough to receive a charging
scoop on either side of the horizontal eduction pipes. The object of our
improvement is, to diminish the contact of the gas with a surface heated high
enough to cause it to deposit some portion of its carbon, and thus to produce a
richer gas or a larger quantity of equally rich gas from a given quantity of
coal.
Under this head we claim the elongation of the eduction pipes of retorts
used for making gas for illumination along or near their axes.
Another part of our Invention is a process for obtaining light by means of
platinum heated to whiteness by coal gas or peat gas. It is known that when
water is decomposed, and the resulting hydrogen burnt within a small cage
made of platinum wire or platinum foil in such a manner as to heat the metal
to whiteness, the platinum becomes luminous, and remains so long as its tem-
perature is maintained; but it is equally well known that hydrogen gas
resulting from the decomposition of water is not readily obtainable under the
generality of circumstances where light is required. Our improvement con-
sists in replacing hydrogen gas from water by the coal gas, which is to be
obtained almost universally, and which answers the purpose, or by peat gas.
For putting our improvement into operation we prefer to burn the gas either
by itself or mixed with atmospheric air within a cylinder greater in height and
diameter, and made of platinum wire, more coarse as the quantity of gas
burned within it in a given time is greater; the only practical rule that it is
necessary to give being, that all the metal be placed with respect to the flame
in the best position for becoming white hot. The advantages which result
from this part of our Invention, are, first, with respect to ordinary coal gas, that
we obtain more light in proportion to the quantity of coal gas consumed than
is the case when platinum is not used; and, secondly, that by its means we
obtain a good light by the combustion of peat gas, or of coal gas of inferior
quality.
Under this head we neither claim nor restrict ourselves to the use of any
particular form or dimensions of the platinum apparatus. What we claim is,
the use of coal or peat gas, mixed or not with air, for heating platinum wire or
foil to whiteness, and thereby producing light.
A former Patent has conferred on one of us the exclusive right to purify
coal gas by a solution of muriate of iron mixed with porous materials, and also
by muriate of iron, decomposed by lime into chloride of calcium and oxide of
iron, and made porous by suitable materials. One part of the present Invention
consists in combining known processes so as to obtain the last-named purifying

page_text: materials. We decompose sulphate of iron in solution by its equivalent
quantity of chloride of sodium, and, having separated by known means the
resulting sulphate of soda, we add to the solution of muriate of iron concentrated
by evaporation, first, enough dry sawdust or other suitable matter to absorb it,
and then enough hydrate of lime to decompose it into chloride of calcium and
precipitated oxide of iron. We purify coal gas with this mixture disposed in
dry purifyers, and afterwards extract from the used materials by any ordinary
processes adapted for that purpose sulphur, cyanogen, and muriate of ammonia.
Sometimes we modify the purifying material in the following manner :-Wo
mix equivalent quantities of ground or granulated sulphate of iron or chloride
of sodium with the other of those salts in solution, absorbed into sawdust or
other suitable matter, and then stir in an equivalent of hydrate of lime. This
modified material, used in dry purifyers for purifying coal gas, subsequently
affords by lixiviation a mixed solution of sulphate of soda and muriate of
ammonia, and sulphur, and cyanogen may also be extracted from it as in the
former case. We also sometimes replace sulphate of iron by sulphate of
copper when the resulting oxide of course is the oxide of that metal instead of
the oxide of iron.
We claim under this head the combination of processes above described
for making a purifying material containing chloride of calcium and precipitated
oxide of iron or copper. And we claim the composition of the modified
material as described. We claim also the use of both kinds of materials for
purifying coal gas.
Another part of our Invention consists in purifying coal gas by means of a
cheap material made by mixing refuse sulphate of lime or gypsum in a finely
divided state with sulphate of iron. The sulphate of iron should cither be
ground fine or granulated and mixed with sawdust or other matter suitable for
separating its particles, or it may be merely mixed in a divided state with the
earthy salt, or absorbed into its mass, or into sawdust, or other porous matter.
The gypsum should be previously baked at a red heat to prevent its tendency to
solidify with water. We use the material thus prepared in dry purifyers in the
way well understood for purifying by hydrate of lime. For the sulphate of
iron other metallic salts may be substituted with similar results, such, for
example, as muriate of iron, sulphate or muriate of zinc, sulphate or muriate
of manganese, or even sulphate or muriate of copper, but we prefer sulphate of
iron. We either make use of the resulting mass as a manure, or we subject
it to certain known chemical processes for obtaining from it an ammoniacal
salt or salts, sulphur and cyanogen.
We claim under this head the purification of coal gas by the use of sulphate

page_text: of lime mixed with any of the metallic salts above named, and the use of the
spent purifying material as a manure.
Another part of our Invention is, the causing of impure coal gas to pass
through dry purifiers charged with a solid porous material, which we make by
mixing in about equivalent proportions hydrated or precipitated oxide of iron
with carbonate of lime, magnesia, carbonate of magnesia or magnesian lime-
stone, in fine powder, or else burned and slaked, either by themselves, or rendered
A mixture of
more pervious to the gas by sawdust or other suitable matter.
precipitated oxide of iron and lime answers the same purpose, and was claimed
by one of us under a former Patent. In each of the above cases oxide of
copper may be substituted for the oxide of iron. All the several compounds,
when they begin to act on the impure gas, purify it from sulphuretted hydrogen
and cyanogen, and having been once made foul, and afterwards placed in
contact with atmospheric air for a few hours, any one of them acquires the
property of purifying coal gas from ammonia also.. The spent materials afford,
by processes well known, cyanogen, sulphur, and ammoniacal products.
We claim under this head the purification of coal gas by mixtures made as
described, whether with hydrated or precipitated oxide of iron or of copper
Another part of our Invention consists in a particular way of using chloride
of magnesium or sulphate of magnesia for withdrawing from coal gas ammonia
and carbonic acid. We take sawdust, or other solid matter calculated to
expose an extensive surface to the gas without opposing great resistance to its
passage, and we cause it to absorb a saturated solution of one or both of the
above named salts, or we mix those salts, singly or together in a divided and
solid state, with sawdust or other suitable matter made damp, and then place the
mixture in dry purifiers, through which we make the gas pass in its way from
the condensers to the gasholders. When the gas ceases to be purified from
its ammonia we take out the contents of the purifier, and wash them to obtain
an ammoniacal solution, and supply their place by a new charge of similar
purifying materials.
We claim under this head the extraction of ammonia and carbonic acid from
coal gas by chloride of magnesium or sulphate of magnesia and water diffused
through sawdust, or other solid matter, capable of exposing an extensive
surface of the reagents to the gas without materially impeding its passage.
Another part of our Invention consists in purifying coal gas by the use of a
solid material containing chloride of magnesium or of calcium, or sulphate of
magnesia mixed with hydrated or precipitated oxide of copper. To make this
purifying material we take sawdust or other suitable matter, wetted with a
strong solution of muriate or sulphate of copper, or else either of those salts of

page_text: copper
in a finely divided state, and mixed with moistened sawdust, or other
suitable matter, and we mix with it enough lime magnesia, or its carbonate or
magnesian limestone, burned and slaked with water, or powdered to decompose
the salt of copper into precipitated oxide of the metal, and a salt of lime or
magnesia, or both; or, instead of making extemporaneously both or either of
the salts of magnesia and lime, and oxide of copper, we mix sulphate of
magnesia or chloride of magnesium, or of calcium ready formed, and in a state
of mechanical division, or in solution with oxide of copper and sawdust, or other
suitable matter. We use these purifying materials in dry purifyers, like
hydrate of lime. They can remove from the gas, ammonia, carbonic acid, and
sulphuretted hydrogen, or they may be used for the latter impurity without the
two former. In the first case, we find it useful to add to them about half an
equivalent of fine carbonate of lime or of carbonate of magnesia, or of both;
and in the latter case we prefer to make either the same addition, or, in lieu
thereof, we add about the same quantity of caustic line or magnesia, or of both
of them. When the used materials will no longer purify the, gas from sulphu-
retted hydrogen, we either take it out from the purifier, and expose it to the
atmosphere, or direct a current of air through it, while in that vessel, opening
or not at the same time a vent-hole in the purifier below the level of the foul
purifying matter. We thus restore to the material its purifying energy, and
this alternate expenditure and restoration of energy we can repeat a number of
times until the material becomes sufficiently charged with sulphur and with
ammoniacal and cyanogen products, or either of them, to render it worth while
to extract it or them in any known way.
.3
We claim under this head the purifying coal gas by the repeated use of a
solid material containing sulphate of magnesia or chloride of magnesium or
calcium, or more than one of those reagents in combination with oxide of
copper, and mixed or not with lime or magnesia, or both, or either, or both of
the carbonates of those earths.
Another part of our Invention is a process for converting the ammoniacal
liquor produced in making gas, or by distilling animal matters into sulphate of
ammonia. By repeatedly using the same portion of hydrated or precipitated
oxide of iron or copper, in conjunction with lime or magnesia, carbonate of
lime or carbonate of magnesia, or any compound of lime or magnesia
susceptible, under the circumstances in which it is used, of being decomposed
by carbonate of ammonia for purifying coal gas, with subsequent exposure to
atmospheric air, the spent material eventually becomes in great part changed
into sulphate of lime or sulphate of magnesia mixed with oxide of a metal.
When this has taken place we mix the spent material in a vat for an hour or

page_text: ..
two, with nearly as much of the ammoniacal liquor as it will decompose; we
next draw off the fluid; we filter it; we perfect the saturation of any ammonia
which it may contain in a volatile state by sulphuric acid, and then we evaporate
it to obtain crystals of ammoniacal sulphate. The same process is followed by
another good result, for the decomposition of the carbonate of ammonia by the
sulphate of lime or sulphate of magnesia reproduces, in the spent material a
carbonate of the earth which fits it for beginning anew the work of purifying
coal gas.
We claim under this head the use of the spent materials above described for
converting solutions of carbonate of ammonia, mixed or not with hydrosulphate
of ammonia, into solutions of ammoniacal sulphate, by which use we also
change the sulphate of lime or sulphate of magnesia in the said mixtures into
carbonate of lime or carbonate of magnesia.
When solid and porous mixtures containing bydrated or precipitated oxide of
iron or copper, or a salt of either of those metals decomposable into hydro-
sulphuret of the metal under the circumstances in which it is used, is employed
to absorb sulphuretted hydrogen from coal gas, and afterwards placed in contact
with atmospheric air, the mixture rapidly absorbs oxygen, and thereby acquires
an elevated temperature, greater in proportion as it is free from moisture. In
certain cases, when the materials are at first, or become by use dry to the
touch, their temperature during the subsequent absorption of oxygen rises
much higher than is desirable. One way of preventing this injurious accession
of heat is, by communicating humidity to the mixture of materials at a proper
time, and constitutes another part of our Invention. We put this improve-
ment into practice either by sprinkling the used purifying materials with water
on removing the cover from the vessel which contains them, or by pipes properly
disposed within the vessel to distribute water over the surfaces of the materials
without removing the cover, or by sprinkling the materials with water after they
have been thrown out of the vessel; or, lastly, by placing the purifier in com-
munication with a steam boiler, and directing through the used materials a
sufficient quantity of the vapour of water to moisten them, and subsequently
submitting them to the influence cf a current of atmospheric air, also directed
through them. We know it to be necessary that the metallic oxides used for
purifying coal gas from sulphuretted hydrogen should be bydrated, that is to
say, combined with a certain proportion of water in a dry state; but our
experience teaches us, contrary to common opinion, that the said articles act
less energetically on the sulphuretted hydrogen in the gas, and that they also
regain their expended energy less suddenly when they contain water in a liquid
state than when they are free from hygrometric water.

page_text: Under this head of our Invention we do not claim the regeneration of the
purifying energy of any spent purifying mixtures by exposing them to atmo-
spheric air. What we claim is, the means we have described for checking the
rapidity of the regenerating action, and consequently preventing the tempera-
ture of the materials from rising to a pernicious height, namely, by wetting.
them with water, or by condensing steam in their mass, either in or out of the
purifier, at any time after they commence to purify the gas, and before they be
put in communication with the atmosphere. Experience has proved to us that
mixtures containing bydrated or precipitated oxide of iron changed into hydro-
sulphuret of iron by purifying coal gas from sulphuretted hydrogen do not
readily reabsorb oxygen, and consequently do not readily recover their purifying
energy at temperatures below 32 degrees Fahrenheit.
Another part of our Invention consists in applying to such used mixtures
during frosty weather atmospheric air artificially warmed to about 60
degrees Fahrenheit by the ordinary operations of the "retort house," or in
any other convenient manner. The warmed air may be used there or conducted
thence to the purifyers by suitable pipes, in which a draught is established by
any known means.
We claim under this head the use of air artificially warmed, for promoting
in cold weather the regeneration of hydrated oxide of iron in mixtures which
have been used for purifying coal gas from sulphuretted hydrogen, whether the
warmed air be conveyed to the used purifying mixtures, or the latter be carried
to the warm air.
Another part of our Invention is, the use of phosphate of lime dissolved in
hydrochloric acid for purifying coal gas, and for decomposing the ammoniacal
liquors produced in making gas, and in the distillation of animal matters, and
the application of the products as manure. To put our improvement into
practice we dissolve bones or other form of phosphate of lime in hydrochloric
acid. We prepare this solution for purifying gas by mixing it with sawdust
or other suitable solid matter, and then we expose it to the impure gas in dry
purifiers. To use the solution for decomposing ammoniacal liquors we add one
of the fluids to the other until the hydrosulphuric and carbonic acids com-
bined with the ammonia have escaped. To facilitate the transport of the
product, and its application as a manure, we heat it in pans, until it becomes
dry. The product of the purification of gas is also a good manure, mixed as it
is with the sawdust or other absorbent matter used.
We claim under this head the use of a solution of phosphate of lime in
hydrochloric acid for purifying coal gas, and for saturating ammoniacal solu-
tions; and we claim also the use of the products as manures.

page_text: Another part of our Invention are, certain processes for obtaining, in an
economical manner, one of the reagents which we use for purifying gas,
namely, chloride of calcium. In certain chemical works hydrochloric acid gas
is a residuary product, not only of no value, but even costly to get rid of with-
out nuisance to the neighborhoods. One of our processes consists in causing
hydrochloric acid gas to pass in a heated state over beds of lime or carbonate
of lime in its way from the furnaces where it is generated to the condensers,
where it would else become absorbed into water. We construct our beds of
lime or carbonate of lime on the bottoms of the ordinary conduits, arranging
two conduits in a line, and working and discharging them alternately. When
the lime in one passage has become converted into chloride, the draught
through it is turned into the neighboring passage by means of dampers
arranged for that purpose, and the finished charge withdrawn by doors made at
convenient distances. When this is done the bed is recharged with lime or
its carbonate, in readiness to receive the current of hydrochloric acid after it
shall have saturated the lime in the second conduit. When this saturation is
completed the dampers are reversed, so as to direct the acid gas again into the
first conduit, while the charge of the second is being withdrawn by its doors,
preparatory to recharging it a second time, and thus continually. By our
second process we obtain hydrochloric acid in a concentrated state, preparatory
to its saturation in a fluid form by lime or its carbonate, or to its application to
other uses.
For this purpose we work with only one conduit, leading from the
furnaces where the hydrochloric acid is generated. We line this conduit by
glazed bricks or tiles or sandstone, and so construct its bottom that any fluid
formed within it shall escape by a pipe adjusted to its lowest part. We arrange
in a line or lines along this conduit a number of porous earthenware vessels
standing on its floor, and built into its arch or cover up to their necks. We
fill these vessels with water, and make them communicate by means of syphons
with one another, and with a reservoir of water, placed with its highest part
on the same level as the mouths of the earthenware vessels. By well-known
arrangements we keep the water at a constant level in the reservoir, and, con-
sequently, at a constant level also in the earthenware vessels which communi-
cate with it. The consequences of this arrangement are, that the water con-
tained in the vessels within the heated conduit is speedily raised to a tem-
perature of 212 degrees Fahrenheit, and that the gaseous contents of the con-
duit are reduced to that temperature, or nearly so, and that the water which
exudes through the porous carthenware absorbs as much hydrochloric acid gas
as it can combine with. Now, as strong hydrochloric acid is condensible at a
temperature above 212 degrees Fahrenheit, and as the vapour of water is not

page_text: condensible at that temperature, the strong acid flows down the outsides of the
porous vessels, and runs in a stream to the most depending part of the passage,
where it escapes by the pipe placed for that purpose. By treating the acid so
obtained with lime or its carbonate we obtain chloride of calcium or muriate
of lime, with hardly any cost for evaporation.
We claim under this head making chloride of calcium, by causing the
hydrochloric acid gas which results from the decomposition of common salt by
sulphuric acid to act on lime or carbonate of lime on its passage from the fur-
nace where the decomposition is effected. And also the collecting of concen-
trated hydrochloric acid for making chloride of calcium or other purposes, by
condensing hydrochloric acid gas in water, by means of earthen vessels built
into a conduit or flue, conducting from furnaces in which chloride of sodium is
decomposed by sulphuric acid, and containing water kept at about 212 degrees
Fahrenheit by the heated products of the said furnaces.
Another part of our Invention is, a new way of using certain forms of car-
bon for purifying coal gas and obtaining ammonia therefrom. It consists in
causing the material alternately to absorb impurities from the gas, and to dis-
charge them under the influence either of heat or of a current of air or steam
directed through the purifying material. To put this part of our Invention
into practice we fill a dry lime purifier or other convenient vessel with animal
charcoal in coarse powder, and direct impure coal gas through it, until it no
longer issues from the vessel pure. We then send the gas in another direction,
and turn through the foul material a current of steam or air heated, or other-
wise receiving the volatile products into any desirable acid, or other substance
calculated to fix the ammonia, or else condensing the ammonia combined with
carbonic and hydrosulphuric acids, by water or by the abstracting of heat in
any suitable apparatus. If steam be used it brings away with it nearly the
whole of the ammonia, but it damps the purifying material, which then needs to
be dried by a current of hot air, or otherwise, if air be used in the first instance
to bring away the ammonia, part of it becomes sulphate of that base, and
must be removed by washing. In addition to or without the introduction of
air or steam among the purifying material it may be heated by steam or hot
water contained in a jacket around the vessel or in pipes within it; or the foul
material may be removed from the purifier, and heated to about 212 degrees
Fahrenheit, in any close vessel adapted for that purpose. Coke, wood char-
coal, or peat charcoal, may be substituted for animal charcoal in the process
above described, but with inferior results.
:
We do not claim under this head the exclusive use of any form of carbon.
for absorbing the impurities of coal gas; our claim being for the means we have

page_text: described for making coke and charcoal repeatedly useful for purifying coal
gas, and for obtaining its ammonia by their agency.
Another part of our Invention consists of certain processes by which we
obtain prussiate of potash, prussiate of soda, and prussiate of ammonia from
prussiate of lime. With respect to prussiate of potash, our process is, to mix
well together equivalent quantities of prussiate of lime and sulphate of potash
or carbonate of potash previously dissolved in separate portions of water, and
then, after subsidence of the sulphate or carbonate of lime which forms, to
evaporate and crystallize the clear solution. We make the prussiates of soda
and of ammonia in like manner by substituting the sulphates or carbonates of
. the respective bases for the sulphate or carbonate of potash.
We claim under this head the manufacture of the prussiates of potash, soda,
and ammonia, by decomposing solutions of the sulphates or carbonates of those
bases by solutions of prussiate of lime.
Another part of our Invention is a process for obtaining carbonic acid gas
for converting the hydrosulphate of ammonia in gas liquor into carbonate of
ammonia, and for other useful purposes to which carbonic acid is applicable.
It is known that hydrosulphate of ammonia is decomposable by carbonic acid,
and that hydrosulphate of ammonia exists in gas liquor. To change it into
carbonate of ammonia we proceed as follows:-We make a mixture of dent-
oxide of copper and charcoal or other form of carbon, in fine powder, in the
proportion of twelve parts by weight of the former to one part of the latter, and
introduce the mixture into a retort made red hot and furnished with an educ-
tion pipe passing through cold water, and finally plunging into gas liquor. The
formation of carbonic acid gas soon takes place by the union of the carbon with
the oxygen of the metal, and, combining with the base of the hydrosulphate of
ammonia contained in the gas liquor, converts it into carbonate, causing hydro-
sulphuric acid to escape. When the carbonic acid gas ceases to come away
nearly all the carbon will have disappeared from the retort, and the copper
which it contains becomes reduced to the metallic state; we then draw the
charge, and leave it to become cold while a second charge of similar materials
is being worked off, during which time the copper reabsorbs oxygen from the
air, and becomes again dentoxide of copper, which may then be used anew
with fresh carbon.
We claim under this head making carbonic acid gas for converting hydro-
sulphate of ammonia into carbonate of ammonia, and for all other purposes in
the arts, by exposing a proper mixture of dentoxide of copper and carbon in
powder to a red heat in suitable vessels.
Another part of our Invention is a process for consolidating peat to be used

page_text: in furnishing gas or charcoal, or for fuel. Our process is as follows:-Without
previously drying the peat we treat it with water by a mill, in a way similar to
that in which chalk is treated for the manufacture of whitening, and which is
well understood. The resulting liquor is made to pass through a strainer of
wirework fine enough to prevent the passage of the large fibres into tanks or
backs cut in the earth or built upon the surface of the ground, if necessary, and
where it is left to deposit the finer parts of the peat. When this is effected the
supernatant liquor is run off from the deposit, and the magma taken out from
the tanks or backs and dried, either by the air, by the sun, or on arches of
bricks or other absorbent material heated by flues underneath.
We claim under this head the separation of the grosser from the finer parts
of peat, and the consolidation of the latter by the process above described.
In witness whereof, we, the said Richard Laming and Frederick John
Evans, have hereunto set our hand and seals, this Twenty-first day
of October, One thousand eight hundred and fifty.
RICHARD (L.S.) LAMING.
FREDERICK JOHN (L.s.) EVANS.