IMPROVE- MENTS IN THE PROCESS AND MANNER OF MAKING GAS FOR ILLUMINATING, HEATING, AND OTHER PURPOSES, A PART OF WHICH MAY ALSO BE APPLIED TO THE PRODUCTION OF METALLIC OXYDES
Year: 1863

page_text: LETTERS PATENT to Henry Holdrege, Engineer, of Irvington, State of
New York, United States of America, for the Invention of "IMPROVE-
MENTS IN THE PROCESS AND MANNER OF MAKING GAS FOR ILLUMINATING,
HEATING, AND OTHER PURPOSES, A PART OF WHICH MAY ALSO BE APPLIED TO
THE PRODUCTION OF METALLIC OXYDES."-A communication from William
Henry Gwynne, resident at the City and State of New York, United
States, aforesaid.
Sealed the 23rd May 1864, and dated the 2nd December 1863.
PROVISIONAL SPECIFICATION left by the said Henry Holdrege at the
Office of the Commissioners of Patents, with his Petition, on the 2nd
December 1863.
I, HENRY HOLDREGE, Engineer, of Irvington, State of New York, United
States of America, do hereby declare the nature of the Invention for "IM-
PROVEMENTS IN THE PROCESS AND MANNER OF MAKING GAS FOR ILLUMINATING,
HEATING, AND OTHER PURPOSES, A PART OF WHICH MAY ALSO BE APPLIED TO THE
PRODUCTION OF METALLIC OXYDES," to be as follows:-
These improvements have relation more particularly to the production or
making of gas from water, and embrace various modes of decomposing water
or the vapour of water, for the purpose of seperating and obtaining the gases
thereof, and also different methods of carbonizing the bydrogen when intended

page_text: to be used for illuminating purposes. A part of this Invention however is
capable of being used for producing or making gas directly from coal without
using water or the vapor of water for the purpose of obtaining hydrogen
therefrom.
A very prominent and essential feature of this Invention in the manufacture
of gas from water consists in the use, in connection or combination with one or
more retorts, of a superheating and distributing chamber or coil, so placed
as to. be subject to the action of the heat applied for heating such retort or
retorts, and perforated with fine holes in the parts coming in contact with the
incandescent decomposing material; so that the vapor of water admitted into
such chamber or coil shall be heated therein to about the temperature of the
incandescent decomposing material immediately before it is brought in contact
therewith, and when so brought in contact therewith it shall be in a finely
divided state by being caused to pass through the perforations or holes in such
chamber or coil. Such chamber or coil is called a distributing chamber or
coil because it is the medium of distributing the superheated steam among
the incandescent decomposing materials in a finely divided state. For
convenience and effectiveness such superheating and distributing chamber or
coil may be placed within the retort containing the decomposing material,
and the steam or vapour of water is admitted within it by means of a
steam pipe and valve connecting with a boiler.
Heretofore in the production of bydrogen and other gases from the decom-
position of water by bringing the vapor of water in contact with the incan-
descent material, it has been the practice to introduce the steam or vapor of
water by means of a pipe in a volume according to the diameter of the pipe,
and the pressure of the steam by filling the retort, or tending so to do, caused a
diminution of temperature, making it difficult if not impossible to keep up the
temperature of the retort necessary to the constant production of the hydrogen,
which is of great importance in the successful manufacture of water gas, in
order to keep pace with the constant production of the hydrocarbon vapors
and gases in the carbonizing and mixing retort. By bringing the steam at
high temperature and in a finely divided state in direct contact with a large
surface of incandescent decomposing material, there is insured an immediate
and perfect decomposition of the steam without diminishing the temperature,
thus securing a constant production of the desired gas. In operating the
apparatus the material used for decomposing the steam or water is placed
within the retort and over and upon the distributing chamber or coil (when
such coil is placed within the retort) and heat is then applied to the retort in
the usual manner, and when the retort is heated to a.bright red heat the steam

page_text: or vapor of water is allowed to enter the distributing chamber or coil and is
there superheated, and then passing through the perforations therein. enters
the retort among the incandescent material contained therein and is rapidly
transformed into permanent gas. The retort or retorts may be filled with
different materials to decompose the water, steam, or vapor of water, accord-
ing as one may be more easily obtained than another, or with reference to the
result sought to be effected. The retort may be filled with iron chips,
charcoal, or any like material which has an affinity for oxygen, and which will
thus set free the hydrogen. Or the retort may be filled with anthracite coal
and when heated to redness the steam allowed to pass in, which will at once.
be decomposed into permanent gas and is, then passed off into the coolers and
purifiers and gas holders. To increase the heating surface of the retort a
diaphragm may extend through it at or near its centre; and to further car-
bonize the gas, and increase its illuminating power, bituminous coal or wood
may be placed in the upper part of the retort over which the gas, after it has
passed through the anthracite coal in the lower part of the retort, may be
caused to pass before entering the coolers or other receivers. Or a bench of
three or more retorts may be used, all of which are filled with anthracite coa!
and heated to redness, and the steam decomposed in one retort is caused to pass
through the other retorts in succession the gas taking up an increased quantity
of carbon as it passes through each. A stream of petroleum or rock oil may
also be introduced into the heated retort when filled with coal, wood, or other
material, the effect of which will be that a richer quality of gas will be pro-
duced and with a higher illuminating power. In such case when petroleum
is thus introduced, the poorer kinds of wood or coal, or such material as saw-
dust and the like, which, under ordinary circumstances would be unfit for the
manufacture of illuminating gas, may be made use of and good illuminating
gas be produced at a trifling cost. The retort may also be filled to a proper.
depth with melted metal of any kind capable of absorbing oxygen, in which
case the oxygen combining with the metal will form an oxide of the metal
used; when iron is used, black oxide will be formed; when zinc, white oxide;
and like operations will take place varying with the decomposing material
employed. It is well known that many of these oxides are commercially
valuable. The hydrogen is set free at the same time the oxygen is thus
absorbed, which may be used for heating or in combination with other gases
hydrocarbons, or by means of materials heated to incandescense, for lighting.
In place of the ordinary retort or retorts a cupola of a peculiar construction
may be made use of in making: gas. Such, cupola may be made of iron lined
with fire-brick or of fire-brick alone, and has surrounding it an open space or

page_text: chamber which is to be filled with coke, brick, or other incandescent material
for the purpose hereafter mentioned. The enclosing chamber also extends
somewhat higher than and over the top of the cupola; there being free com-
munication at the top between the cupola and its enclosing chamber. A
cover fitting over a hole in the top through which the cupola is charged is
tightly luted down while the gas is being made. At or in the bottom is a
grate to kindle and heat the coal, and through this air or steam is to be
supplied as desired. From near the bottom of the enclosing chamber extends
a pipe which connects with a blower put in motion by any convenient power.
The cupola is charged with anthracite or other coal and the surrounding
chamber filled with coke, brick, or similar suitable material to decompose
the tarry or carbon vapors that may be held by the gas. Fire is then
kindled on the grate, the coal becomes heated, and the gas rising from the
burning mass of coal is exhausted by the fan blower and is compelled to pass
down through the incandescent material in the enclosing chamber by which
the tarry or carbon vapors are decomposed, and it then passes to the coolers
and gas holders. The suction of the blower creates all required draught to
keep the coal in the cupola constantly burning. By the use of such a cupola
the coal heats and decomposes itself, and the whole apparatus is simple, cheap,
and economical in operation. Air alone may be admitted under the grate in
the lower part of the cupola, or steam or the vapor of water may be caused
to pass into the burning mass of coal. If air alone is admitted the gas pro-
duced will be that derived from the coal, but if steam is discharged into the
burning coal an increased quantity of hydrogen will be obtained. This cupola
is thus capable of being used for the manufacture of gas directly from coal
without making use of the vapor of water, or steam or water vapor may be
decomposed by its operation to increase the quantity of hydrogen; the other
modes described have particular reference to the production or making of
water gas so called. A part also of the Invention may be usefully applied to
the production of metallic oxides.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed.
by the said Henry Holdrege in the Great Seal Patent Office on the
2nd June 1864.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
HOLDREGE, Engineer, of Irvington, State of New York, United States of s
America, send greeting.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Second day of December, in the year of our
Lord One thousand eight hundred and sixty-three, in the twenty-seventh
year of Her reign, did, for Herself, Her heirs and successors, give and grant
unto me, the said Henry Holdrege, Her special licence that I, the said
Henry Holdrege, my executors, administrators, and assigns, or such others as
I, the said Henry Holdrege, 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-
MENTS IN THE PROCESS AND MANNER OF MAKING GAS FOR ILLUMINATING, HEATING,
AND OTHER PURPOSES, A PART OF WHICH MAY ALSO BE APPLIED TO THE PRODUCTION
OF METALLIC OXYDES," being a communication to me from William Henry
Gwynne, a person resident at the City and State of New York, United States
aforesaid, upon the condition (amongst others) that I, the said Henry
Holdrege, 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 Henry Holdrege, 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 :-
The said Invention or improvements have relation more particularly, and to
the greatest extént, to the production or making of gas from water or the
vapor of water, and embrace and include various modes of decomposing water
or the vapor of water for the purpose of separating and obtaining the gases
thereof, and also different methods of carbonizing the hydrogen when that gas
is to be used for illuminating purposes.
A part of this Invention, however, is capable of being applied or used for
the production of metallic oxydes in connection with the decomposition of
water, and one method described may be used for the manufacture of gas
either in combination with or separate from the use of the vapor of water for
the purpose of increasing the quantity of hydrogen.
. A prominent and important feature of this Invention, in its application to

page_text: the manufacture of gas from water, consists in the use, in combination with
one or more suitable retorts, of a superheating and distributing chamber or
coil, and which may be so placed as to be subject to the action of the heat
applied for heating such retort or retorts, so that the vapor of water admitted
into such chamber or coil shall be heated therein to about the temperature of
the incandescent decomposing material in the retort immediately before it is
brought in contact.therewith, and which superheating chamber.or coil is .per-
forated with fine holes, by means of which the vapor of water when superheated
in such chamber or coil is brought in contact with the incandescent decom-
posing material in a finely divided state, and in a condition as dry as possible;
- such chamber or coil is called a distributing chamber or coil because it is
the means of distributing the superheated steam among the incandescent
decomposing materials in a finely divided state.
Figure 1, Plate 1, is a transverse section of a retort with a metallic or other
box having a circulating, chamber D, arranged therein; and Figure 2 is.a
longitudinal section of the same; Figure 3 shows the interior circulating
passage and connecting pipe; and Figure 4 shows the perforated cover, which
is represented with a curved top. When steam is,admitted into the box B
through the pipe E, which may connect with any convenient source of supply,
it enters passage D and travels entirely around box B before passing through
the cover C into the retort A. Figure 7 shows a distributing coil placed in
the lower part of a retort, and perforated at its inner end for the discharge of
the superheated steam. The perforations in the distributing chamber or coil
are usually made about one-eighth of an inch in diameter, but the oxydation
of the metal will soon cause them to be contracted.
In the operation of making water gas, it has heretofore been the practice
to produce the hydrogen and the other gases resulting from the decomposition
of water, by bringing the vapor of water in contact with incandescent charcoal,
coke, or other decomposing material placed in a suitable retort, from which
said gases are conducted by means of a suitable pipe to a gas retort, where
they meet the hydrocarbon vapors and gases eliminated from some proper gas-
yielding substance. It has also been the practice to introduce the steam or
vapor of water by means of a pipe, into some part of the hydrogen retort, into
which its issues from the open end of the pipe in volume corresponding to the
diameter of the pipe, and the pressure of the steam filling the retort, or tending
to do so, caused a diminution of the temperature, and rendered it difficult if
not impossible to keep up the temperature of the retort necessary for the
constant production of the bydrogen, and which is of great importance in the

page_text: successful manufacture of water gas, in order to keep pace with the constant pro-
duction of the hydrocarbon vapors and gases in the carbonizing and mixing
retort.
This Invention consists in an improvement in such process whereby there is
obtained a more uniform mixture of gases eliminated from coal and water,
or their equivalents, in separate retorts, by supplying the hydrocarbon gas
retort. with gases that are eliminated from the vapor of water in a separate
retort in a manner that ensures, as far as possible to such operations, a
constant and uniform supply of such gases, viz., by passing the steam,
previously heated to about the temperature of the incandescent decom-
posing material, in a finely devided state through the mass of said
decomposing material in the decomposing retort, and conducting the gases
thus formed to the hydrocarbon or mixing retort. The effect of bringing the
steam at high temperature in a finely divided state in direct contact with a
large surface of incandescent decomposing material, is to ensure an immediate
and perfect decomposition of the steam without diminishing the temperature
and thus securing a constant production of the desired gases.
In operating the apparatus the material used for decomposing the steam or
water is placed within the retort over and upon and around the distributing
chamber or coil (in cases where such coil or chamber is placed within the
retort, and which is the most economical and convenient arrangement, as the
same heat used to heat the coal will also heat the distributing chamber and
thus superheat the steam), and beat is then applied to the retort in the usual
manner, and when the retort is heated to a bright red heat the steam or vapor
of water is allowed to enter the distributing coil or chamber, where it is
superheated, and from whence it passes by means of the perforations a, a, a,
among the incandescent material contained in the retort, and is rapidly
transformed into permanent gas.
The distributing chamber or coil represented in the Drawings and before
described is considered best adapted for use, but other forms of apparatus may
be used which will embody the same mode of operation and perform the same
functions, as for instance a conducting pipe of zig-zag or other suitable form
laid flat upon the bottom of the retort, and perforated upon its upper surfaces,
and closed at the lower or extreme end. Water instead of steam may also be
admitted into the distributor, care being taken to regulate the quantity so as
to produce the requisite amount of steam without cooling the retort by an
excess of steam at low temperature, which would be the case were an excess of
water to be admitted. The retorts used may be filled with different materials
suitable for decomposing the vapor of water,, according as one is more con-

page_text: venient and easy to be obtained than another, or the particular material to
be used may be selected with reference to the whole results sought to be
attained. If it is thought more especially by the operation of the retort and
the use of the distributing chamber and coil in connection with it, to obtain
the hydrogen from the vapor of water, and such gas is then to be conducted
to a retort where it shall meet any hydrocarbon vapor, the retort may be filled
with iron chips, charcoal, or any material suitable for decomposing water vapor,
or the retort may be filled to a proper depth with melted metal of any kind
capable of absorbing oxygen, in which case the oxygen as the steam is decom-
posed and the hydrogen set free, will combine with the metal, producing
oxydes of the metal used. When melted iron is used black oxyde will be
produced, if zinc is used white oxyd will be formed, and like operations will
take place varying with the decomposing material employed, and it is well
known that many of the oxydes are commercially valuable.
Figures 1 and 2, Plate 2, are two views of a retort, suitable for so
producing metallic oxydes. At the bottom of the retort a distributing coil,
such as is shown in Figure 7, Plate 1, or a distributing chamber to heat the
steam and deliver it in small jets through the decomposing material, is placed,
and the retort is then filled with a quantity of decomposing material, say,
sufficient when melted to cover the retort three or four inches in depth over
the distributing pipe D, Figure 1, Plate 2; or a suitable stream of melted
metal may be run directly into the retort by the pipe E, Figure 2, Plate 2.
When sufficient decomposing matter is in the retort, the valve F, Figure 2,
Plate 2, is opened, and steam admitted into the circulating or distribu
pipe D, Figures 1, 2, Plate 2, where it is superheated and distributed through
the red hot material, and is decomposed into oxygen and hydrogen, the former
gas combining with the metal, and the latter, set free, passes out of the stand
pipe G, Figure 2, Pl. 2, into the washer and purifiers, and thence to. a
gasometer, where it may be stored; or it may before being purified pass into
another retort containing hydrocarbons, and made into illuminating gas. If
oxydes of lead or zinc, or other metals which sublime at high temperatures,
be wanted, it will be advisable to attach a subliming chamber or retort for
that purpose.
Water, or the vapor of water, may also be decomposed by the use of
hard or anthracite coal, thereby producing gas more cheaply and speedily than
it has been done by other methods. The retort used for that purpose is
represented in Figures 5 and 6, Pl. 1; Figure 5 being a longitudinal section,
and Figure 6 a vertical front section of the same. A diaphragm 6 runs
through the centre, for the purpose of increasing the heating surface over

page_text: which the steam must travel before it can leave the retort. In the bottom of
the retort is placed the superheating and distributing apparatus shown in
Figure 7, Pl. 1, and the retort is then filled with anthracite coal on both sides
of the division or diaphragm b, and when heated to a red heat steam is
admitted through the cock or valve F into the distributor D, where it is
superheated, and from whence it passes by means of the perforations a, a,
into the heated coal, where it is at once decomposed into permanent gas. If
any steam escapes decomposition in the lower part of the retort, it will be
decomposed in the upper layer of coal above the diaphragm b; the gas
then passes off into the coolers and purifiers, and thence to the gas holder,
where it is stored for use.
For the purpose. of carbonizing the gas more highly than can be done with
one retort; and thereby produce illuminating gas, a bench of two or more retorts,
as shown in Figure 8, Pl. 1, may be made use of. Such retorts are made of
iron, clay, or other suitable material used for retorts, and are set in an oven
built of brick in the usual manner of gas works, and known as a bench. To
increase the heating surface of such retorts, diaphragms 6 may be placed in them
in the manner before described, and as shown more particularly in Figure 5, Pl. 1.
In one of such retorts is placed a superheating or distributing coil D, D, to
which is attached a steam pipe with its valve F, for the purpose of supplying
a certain quantity of steam when required. The retorts are all .then filled
with anthracite coal, their covers luted tightly, and heated to a red heat. The
valve F is then opened, and steam admitted into the coil D, D, from whence
it passes through perforations a, a, as shown in Figure 7, Pl. 1, into the
heated coal, where it is decomposed into inflammable gases. It then passes
through pipe H, Figure 8, into the next retort, and around the diaphragm b
in such retort, and among the .coal in such retort, where it takes up an
increased quantity of carbon, and then passes through pipe J into the last
retort, where it is more fully carbonized, sufficiently for illuminating purposes,
from whence it passes by the discharge pipe K into the coolers and purifiers,
and thence to the gasometer, where it is stored for distribution.
The use of anthracite coal for the purpose of decomposing the vapor of
water in connection with soft or bituminous coal to carbonize the gas obtained
from the vapor of water, and thus make it fit for illuminating purposes, is,
however, in some respects more desirable than the use of anthracite coal
alone, as before described. The arrangement of retorts for such a combined
use of anthracite and soft or bituminous coal, shown in Figure 3, Plate 2,
which is a perspective view, the enclosing setting being removed so as to
show the position of the retorts and their connections, has been found highly

page_text: satisfactory. The retort A" is filled with anthracite coal, and the use or
object of such retort is to decompose the vapor of water; such retort is also
to be provided with a superheating and distributing box or coil, such as is
shown in Figures 1 and 4, or in Figure 7, Plate 1. Connected with such
retort, thus provided with a superheating and distributing apparatus, is a bent
or U-shaped pipe D', which has attached to it the syphon B¹ and cup C¹.
Water is supplied to such syphon through the cup C', and from thence passes
into: the pipe D', which is exposed to the heat of the oven, where it is
converted into steam before it enters the distributing box or coil before
referred to. By the arrangement of the pipe D¹ the water supplied through
the syphon is converted directly into steam, and no other provision is required
for supplying steam to the distributor. The steam is superheated, as before
described, in the distributing chamber or coil, and is then passed in a finely
divided state into the heated coal in the retort A". From this retort the
hydrogen and other gases, except the oxygen, which is taken up by the
anthracite coal, as they are set free by the decomposition of the vapor of
water, are conducted by a pipe E¹ to the retort B", which is filled with
bituminous coal, through which they pass, and in passing through which they
take up all required carbon to fit them for illuminating purposes. The gases
having been thus carbonized are not conducted directly to the coolers and
purifiers, but pass from such retort B" through an opening 9 into a hollow
core or passage F¹ cast upon the top of the retort, and which is highly heated,
and in passing through such heated passage the gases are further reheated,
after having been carbonized, and from thence they are passed by means of
the stand pipe G' to the coolers and purifiers. The formation of the core F¹
upon the retort furnishes a convenient method of reheating the gas after
carbonization, but other arrangements of parts may be used for the same
purpose. This reheating of the gases after they have been carbonized is
found to greatly improve its illuminating qualities. The hydrogen retort A"
if made about the size of the carbonizing retort B" may be divided into two
parts by the partition H', each of which is to be provided with its syphon tube
to convert the water into steam, a distributing chamber or coil to superheat
and distribute the steam, and a carbonizing retort with a suitable attachment
to reheat the gas after it has been carbonized. By such an arrangement one
hydrogen and carbonizing retort may be constantly in operation. Actual
experiment has demonstrated that a single charge of anthracite coal, so used
to decompose the vapor of water and thus furnish a constant and abundant
supply of hydrogen, is sufficient for a large number. (over fifty) of charges of
soft coal in the carbonizing retort; and the supply of bydrogen so obtained

page_text: from the decomposition of water takes up so nearly all the carbon contained
in or produced from the soft coal, that the formation of coal tar, except in the
smallest quantities, is entirely prevented. Cannel coal and other coals which
heretofore could not be used in the manufacture of gas, except under great
disadvantages, because producing a gas too rich for practical use, can also by
the above process be used as well as those coals commonly known as semi-
bituminous. The charges of soft coal are also worked off in about half the
time usually required in the ordinary methods of making gas. The use of the
different kinds of coal in connection with each other, substantially as described,
for making illuminating gas thus secures important advantages, and greatly
reduces the cost of manufacture. As will be observed the action of the
anthracite coal in the hydrogen retort, so-called, is to decompose the super-
heated steam and take up or absorb the oxygen, setting free the hydrogen,
which is afterwards carbonized. Though for some reasons the use of anthra-
cite coal for such purposes is preferred, other substances, as charcoal, iron
chips, or any material suitable for decomposing the water vapor and absorbing
the oxygen, may be used in the place of it, and substantially the same results
be produced. Where anthracite coal can be conveniently obtained its use is
preferred: If for any reason the use of but a single retort is convenient or
possible, and it is also desirable to carbonize the gas produced, so as to render
it fit for illuminating purposes, a stream of petroleum or other liquid hydro-
carbon may be admitted into the retort. In such case also the retort may be
filled with inferior materials, such as chips, sawdust, and similar articles,
which of and by themselves would not produce a gas sufficiently rich for
illuminating uses. The retorts used may be varied in form to suit any kind
of gas works, or as most convenient under particular circumstances and con-
ditions, and they may be made of iron or any suitable material. The use of
retorts in the manufacture of illuminating gas may, however, be wholly
dispensed with, the coal being heated in a cupola, and the gas arising
therefrom being exhausted in such a manner that it is compelled to pass
through a space filled with coke, brick, or other incandescent material,
whereby it is freed from all tar and other impurities which may be mixed
with it when it rises from the cupola.
Figure 4, Plate 2, is a vertical longitudinal section of such a cupola with
its exhauster, and Figure 5, same Plate, is a plan or top view of the same.
L represents a cupola, made in the form of an upright cylinder. of cast iron
lined with fire-brick, or of any suitable material. The bottom of such cupola
is provided with a fire-grate M of any desirable construction, set on a circular

page_text: plate of iron, or on a suitable base of brickwork. N is a cylinder surrounding
the cupola L, between which cylinder and cupola is an annular ring or space O.
which is filled with coke, fire-brick, or other material suitable to take up or
separate the impurities that may be in the gas as it rises from the cupola. The
cylinder N is somewhat higher than the cupola, so as to form a space P, for
the gas to accumulate, and from which it is drawn down through the annular
space O. To the top of the cylinder N is firmly luted a cover Q, through
which is an opening R, which is closed with a lid S; the joint between the
lid and cover is made tight with melted metal or in any suitable manner.
Through this lid the cupola is charged with coal. The gas arising from the
burning mass of coal is exhausted by a fan blower T, placed on the side of the
cylinder N, and communicating with it through a pipe V, which extends into
the annular space O just above the grate or bottom plate of the cupola, so that the
gas is compelled to pass down through the incandescent material in the annular
space before it reaches the discharge pipe V. Fire having been kindled on
the grate M, and the necessary air to support combustion being admitted
through the register or valve U, the cupola is charged with anthracite or
other coal, the entire body of coal soon becomes one burning mass, and the
material which fills the annular space becomes also incandescent. The action
of the blower creates a draught which causes the atmospheric air to rush in
through the register in sufficient quantity to keep up combustion in the cupola,
the quantity of air admitted being regulated by the register.
By such an apparatus the use of a retort is dispensed with, and the coal
heats and decomposes itself in the cupola, which being surrounded by brick or
other incandescent material, does not lose any of its heat by radiation. The
cupola also is not liable to crack, or should it crack the gas escaping is not
lost but is retained in the annular space O, and exhausted from thence with the
rest by means of the exhauster. The charging and discharging of the cupola
is comparatively easy, and the former can be done almost entirely by machinery.
The discharge should be so arranged that no air should enter as the grate is
tilted. The whole apparatus is simple and cheap of construction and economical
in operation. Air alone may be admitted into the cupola through the register
or valve U, or the vapor of water may be admitted through a pipe U, to
facilitate the supply of bydrogen. This arrangement of cupola is thus capable
of being used for making gas directly from coal without the use of the vapor
of water, or the vapor of water to increase the quantity of hydrogen may be
admitted into the burning mass, where it will be decomposed and give up its
hydrogen for carbonization.

page_text: The particular form or arrangement of the different kinds of apparatus
herein-before described for effecting the results mentioned is not essential, as
many changes and modifications thereof may be made without changing the
principle of their action and operation; what I desire to secure and protect
by Letters Patent is,―
The herein-before described mode or process in the manufacture of hydro-
carbon illuminating gas of supplying the hydrocarbon retort with gases
eliminated from the vapor of water in a separate retort, by passing steam,
superheated to about the temperature of the incandescent decomposing:
material in a finely divided state, through the mass of such decomposing:
material, substantially as and for the purposes set forth.
I also claim the distributing box B, with its circulating and heating
passage D, and perforated cover C, Figures 1 to 4, Plate 1, and the super-
heating and distributing perforated coil D, Figure 7, Plate 1, or their
equivalent, for the purpose of superheating the vapor of water and distributing.
the same in a finely divided state through the incandescent decomposing
material, and operating substantially as set forth.
I also claim the decomposing of steain by passing the same through melted
metals or ores, for the purpose of obtaining the hydrogen therefrom for
illuminating or henting purposes, and at the same time producing metallic
oxydes, substantially as set forth.
I also claim obtaining gases for heating, lighting, and other purposes by
decomposing highly heated and finely divided jets of steam by means of
anthracite coal, substantially as described.
I also claim carbonizing gas for illuminating purposes by passing it through
a number of retorts of anthracite incandescent coal, substantially as set forth
and described.
I also claim the process of making illuminating gas by the use of anthracite
coal, or other suitable material to decompose the vapor of water and absorb
the oxygen, setting the hydrogen free, in combination with the use of bituminous
or soft coal to carbonize such hydrogen so obtained by the decomposition of
water, substantially as set forth.
I also claim the construction and arrangement of the retorts A" and B",
Figure 3, Plate 2, with their connections B', D, E, F, and G¹, substantially
as described, for the purpose of making illuminating gas by the decomposition
of the vapor of water, and then carbonizing such gas by the use of soft coal.
I also claim the reheating of illuminating gas after the same has been
carbonized for the purposes set forth.
I also claim introducing into a retort containing coal, wood, or other

page_text: material from which gas can be obtained, a stream of petroleum or other
liquid hydrocarbon, for the purposes set forth.
I also claim the within described process of producing illuminating gas by
exhausting the products of combustion of a body of coal from a cupola or its
equivalent through a quantity of incandescent material, substantially as and
for the purposes set forth.
I also claim the employment or use of a cupola surrounded by an annular
space or surface, in combination with an exhausting fun, or its equivalent,
applied and operating for producing illuminating gas, substantially in the
manner shown and described.
In witness whereof, I, the said Henry Holdrege, have hereunto set my
hand and seal, this Third day of May, A.D. 1864.
HENRY HOLDREGE. (L.S.)