IM- PROVEMENTS IN THE MANUFACTURE OF GAS, AND IN APPARATUS EMPLOYED THEREIN
Year: 1873

page_text: LETTERS PATENT to William Henry Maitland, of Saint Swithin's
Lanc, in the City of London, Engineer, for the Invention of “IM-
PROVEMENTS IN THE MANUFACTURE OF GAS, AND IN APPARATUS EMPLOYED
THEREIN."—A communication from abroad by Orin Charles Hoffman,
PROVISIONAL SPECIFICATION left by the said William Henry Maitland
at the Office of the Commissioners of Patents, with his Petition,
on the 28th August 1873.
I, WILLIAM HENRY MAITLAND, of Saint Swithin's Lane, in the City
of London, Engineer, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN THE MANUFACTURE OF GAS, AND IN APPARATUS EMPLOYED
THEREIN," to be as follows:—
This Invention relates to the production of illuminating gas of high
candle power from liquid hydrocarbons combined by a peculiar process
with atmospheric air, or with gas of low candle power derived from the

page_text: distillation of certain inferior qualities of coal, or with other suitable
gaseous or aeriform matter.
The Invention consists in a process or method of making illuminating
gas by passing atmospheric air through or in contact with a volatile
hydrocarbon until saturated therewith, and then subjecting in a suitable
retort the air and hydrocarbon vapor thus combined to a heat sufficient
to convert the whole into a permanent or fixed gas.
The Invention also comprises the production of illuminating gas by
the use, in lieu of light hydrocarbons as aforesaid, of heavy or crude
petroleum, there being in this modification of the Invention provision
made for subjecting the heavier portions of the petroleum to destructivo
distillation simultaneously with the treatment by heat of the vapor
charged air drawn through or from the petroleum to the retorts.
The Invention also includes the enrichment of illuminating gas (made
by ordinary methods, but from inferior materials, and hence by itself
practically worthless for illumination) by treating the same in connection
with light or heavy liquid hydrocarbons, according to one or the other of
the two modifications of the Invention just set forth.
The Invention also embraces an apparatus for carrying into effect the
aforesaid process in each of the several modifications thereof, and com-
prising an air or gas forcing device, a carburetter, and a retort, the whole
arranged to insure the passage of air or inferior quality of gas to the
carburetter, the charging of the said air or gas with hydrocarbon vapor,
and its subsequent passage to a retort for such treatment by heat or
distillation, whereby the vapor and the air or gas are converteded into a
fixed gas of great illuminating power.
! Also the external application of steam or hot air as a means of
maintaining the hydrocarbon at the temperature most favorable to the
carburetting of the air or inferior gas, without the contact with the
carburetter of flame or extreme heat, which would constitute an obvious
source of danger from fire.
Also the combination with the forcing pump or equivalent device of
the apparatus of a registering mechanism, whereby the volume forced
into the carburetter is made to indicate, the quantity of gas produced.
Also the combination with the carburetter of a transparent gauge
containing a thermometer and hydrometer, whereby the temperature

page_text: and density of the hydrocarbons being made evident, the richness of the
vaporized volume evolved therefrom and consequently the resultant
illuminating gas may be readily and accurately known.
Also the combination with the registering pump of the apparatus of
cone pulleys or their equivalents, for changing or adjusting the speed of
the same, so that the volume admitted to the carburetter may be readily
regulated to meet the conditions incurred by the temperature and density
at any given time of the hydrocarbons.
Also the combination with the carburetter of a pipe and forcing device,
whereby, when required, the heavier portions of the hydrocarbon, as
when crude petroleum is used, may be forced to the retort for distillation,
with the vapor charged air or gas passed simultaneously to the retort
from the said carburetter.
Also the construction of the carburetter with heating surfaces, so
arranged as to permit the economical and efficient employment of steam
or hot air, to replace to the hydrocarbon the heat rendered latent by the
vaporization, and which if not thus replaced would reduce the temperature
of the liquid below that at which the charging of the air or gas with
vapor is feasible.
Also an apparatus for carrying into effect the herein-before mentioned
process in any of its modifications by means of a caloric engine, so
called, whereby the apparatus may be supplied with the requisite heat
from the motor operating the moving parts of the apparatus when such
are used or applied to other purposes when desired, the air or gas forcing
pump and steam heating appliances, essential under some circumstances,
being dispensed with when the aforesaid engine is adopted for the
purpose indicated.
The carburetter is by preference made in two parts, identical in con-
struction, and connected together by two pipes, one of which forms part
of the inlet pipe and the other part of the outlet pipe, the purpose of
which is hereinafter fully set forth. When preferred the carburetter
may be made single. It may be of rectangular or other suitable shape,
and is provided with a sheet metal bottom, underneath which is a steam
chamber; from this project upward radiator tubes, closed at their upper
end. At or near the top of the carburetter is the outlet pipe leading to
or connecting with a retort. The inlet pipe extends downwards nearly.

page_text: to the bottom of the carburetter through the agency of a pipe forming
a part of or continuation of the same. A glass gauge is fitted to the
carburetter similar to an ordinary water gauge except that it is made
large enough to contain a thermometer and a hydrometer. The outer
end of the inlet pipe is open to the atmosphere, and the said pipe is
furnished at any desired point between its two ends with an air pump
or blowing engine, or equivalent air forcing mechanism; this may be
of the rotary kind or on the reciprocating system. Arranged in suitable
relation to this forcing pump or equivalent device is a registering
apparatus, with the usual index fingers and dials, and which being of
well known character and construction needs no description here. This
register is actuated by ratchet wheel operation by a paul or lever
attached to an excentric provided on the rotating shaft of the pump, or
when a reciprocating pump is used by a paul, lever, or like device
attached to an arm on the piston rod and forming part of the valve
motion of the pump.
With the rotary pump there is provided parallel
to its shaft a countershaft, and on the two is arranged a system of
cone pulleys and bands whereby from any given speed of prime mover
the speed of the pump may be regulated on occasion, as herein-after
further explained.
The carburetter being filled (say to about the upper ends of the
radiator tubes, with light petroleum, steam or equivalent hot fluid is
admitted to the chamber below and to the radiator tubes, and the air
pump set in motion to force air inward through the inlet pipe; the
operation is as follows:-The air issuing from the lower end of the inlet
pipe bubbles up through the hydrocarbon to the space above the same,
and in so doing becomes charged or saturated with hydrocarbon, which
it carries off in the form of condensible vapor; from the said spacc the
saturated air is conveyed through the outlet pipe to the retort, which
may be of any ordinary or suitable construction; but which is maintained
at a heat sufficient to ensure what may be termed destructive distillation
of the commingled materials, which are converted thereby into a chemical
permanent or fixed gas of great illuminating power.
It should be mentioned that any regurgitation of the gas in the outlet
pipe is effectually prevented by a valve which is placed at any suitable
point on the said pipe. Inasmuch as the rapid vaporization of the
hydrocarbons by the air or gases rendered latent a great quantity of heat
which if not replaced would soon reduce the temperaturo so low as to

page_text: effectually prevent further volatilization, it is necessary to replace the
heat thus rendered latent, which is done by the agency of the steam
chamber and its radiator pipes which diffuse the requisite amount of
warmth through the bulk of hydrocarbons in the carburetter, steam (or
in lieu thereof hot air or other heated fluid medium) being admitted to
the aforesaid chamber through suitably provided cocks.
As the readiness with which the hydrocarbon is absorbed by the air or
gases is directly dependent upon the density and temperature of the
hydrocarbons it follows that the hydrometer and thermometer in the
glass gauge afford convenient and accurate means of ascertaining the
extent to which carburation occurs, and consequently the richness or
candle power of the illuminating gas produced.
The volume of gas being directly dependent upon the volume of air
or gases introduced the known capacity and registered revolutions or
strokes of the forcing pump enable the quantity of air or gases, and
conscquently the volume of improved gas, to be recorded by the index
fingers and dials of the registering mechanism.
By substituting in the place of atmospheric air coal gas made from
inferior coals, and practically worthless for illumination, such gas will
be enriched and converted into a gas of high candle power, and further-
more in those cases where hydrogen or oxygen gas is available for the
purpose, the same may be substituted in the place of air (or of inferior
coal gas as last stated) and a rich illuminating gas thereby obtained, and
moreover it is designed to include within the general scope of this Inven-
tion the same or analogous employment of any gaseous or aeriform body
which by saturation with hydrocarbon vapor and subsequent treatment
by heat will produce a gas of rich quality or high candle power.
For the use as a carburetting agent of heavy or crude petroleum
instead of naphtha or light hydrocarbons as previously herein set forth,
the carburetter is provided with another pipe (provided with cocks)
extending upward from its lower part to a height somewhat greater
than the carburetter itself, bent at one part to provide a trap, and thenco
carried to the highest point or part of the outlet pipe, whence it passes
through the said pipe to the retort. Situated at any desired point in the
pipe is a rotary or other pump operating to force the lower or heavier
portions of the liquid from the carburetter to the elevated portion of the
outlet pipe, whence it flows simultaneously with the passage to the

page_text: retort of the air (or gas of inferior quality) saturated with the lighter
portions of the liquid in the same manner as in the other modifications
of the Invention herein-before described.
The heavier liquid on entering the retort falls upon the heated surface
of coke, broken stones, metal, or other material provided in the usual
manner, and is distilled into an incondensible gas simultaneously with
the similar treatment by heat of the vapor laden air or gases entering
the retort from the outlet pipe of the carburetter, the products of the
heavy liquid aforesaid and the vapor laden air combining in the
ultimate product an incondensible gas of great illuminating power.
]
From the upper end of the pipe through which the heavy portions of
the liquid are forced, is extended a return pipe so arranged that any
surplus forced into the pipe will follow the return pipe and be returned
to the carburetter.
It will be understood that the illuminating gas passes from the retorts 1
in the usual manner through a pipe to the hydraulic main and to the
gasometer.
In some instances where a caloric or hot air engine is available the
exhaust air from the same may be substituted for the steam used in the
heating or maintaining at the requisite temperature of the hydrocarbon 2
in the carburetter, and moreover the form and construction of the latter
may be modified in various ways to permit the use for this purpose of
either hot air or steam, an ordinary vertical flue boiler under some
conditions being capable of advantageous use in lieu of the carburetter
constructed specifically as herein-before described.
2
The caloric engine gives motion to the air or gas forcing pump,
simultaneously with which the hot exhaust of the said engine passes
through and from a pipe into the heating devices of the carburetter to
heat the contents thereof, as and for the purpose herein-before fully set
forth. The carburetter may in this case be identical with a vertical §
tubular steam boiler, the fire-box and tubes serving the same purpose as
the steam chamber and radiator tubes herein-before described, and the
exhaust after having been thus utilized passing to the stack or uptake.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Henry Maitland in the Great Scal Patent
Office on the 17th February 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
HENRY MAITLAND, of Saint Swithin's Lanc, in the City of London,
Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria by Her Letters
Patent, bearing date the Twenty-eighth day of August, in the year of our
Lord One thousand eight hundred and seventy-three, in the thirty-seventli
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said William Henry Maitland, Her special licence,
that I, the said William Henry Maitland, my executors, administrators,
and assigns, or such others as I, the said William Henry Maitland,
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 thercin 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
"IMPROVEMENTS IN THE MANUFACTURE OF GAS, AND IN APPARATUS EMPLOYED
THEREIN," (a communication from abroad by Orin Charles Hoffman, of
New York, in the United States of America), upon the condition
(amongst others) that I, the said William Henry Maitland, 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 William Henry Maitland, 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, reference being had to the
accompanying Drawings, that is to say:―
This Invention relates to the production of illuminating gas of high
candle power from liquid hydrocarbons combined by a peculiar process
with atmospheric air or with gas of low candle power derived from the

page_text: distillation of certain inferior qualities of coal or with other suitable
gaseous or aeriform matter.
The Invention consists in a process or method of making illuminating
gas by passing atmospheric air through or in contact with a volatile
hydrocarbon until saturated therewith, and then subjecting in a suitable
retort the air and hydrocarbon vapor thus combined to a heat sufficient
to convert the whole into a permanent or fixed gas.
The Invention also, comprises the production of illuminating gas by
the use in lieu of light hydrocarbons as aforesaid of heavy or crude
petroleum, there being in this modification of the Invention provision
made for subjecting the heavier portions of the petroleum to destructive
distillation simultaneously with the treatment by heat of the vapor-
charged air drawn through or from the petroleum to the retort.
The Invention also includes the enrichment of illuminating gas (made
by ordinary methods, but from inferior materials, and hence by itself 1
practically worthless for illumination) by treating the same in connection
with light or heavy liquid hydrocarbons, according to one or the other
of the two modifications of the Invention just set forth.
The Invention also embraces an apparatus for carrying into effect the
aforesaid process in each of the several modifications thereof, and com- 2
prising an air or gas forcing device, a carburetter, and a retort, the whole
arranged to insure the passage of air or inferior quality of gas to the
carburetter; the charging of the said air or gas with hydrocarbon vapor,
and its subsequent passage to a retort for such treatment by heat or
distillation, whereby the vapor and the air or gas are converted into a 2
fixed gas of great illuminating power.
Also the external application of steam or hot air as a means of
maintaining the hydrocarbon at the temperature most favorable to the
carburetting of the air or inferior gas without the contact with the
carburetter of flame or extreme heat, which would constitute an obvious
source of danger from fire.
Also the combination with the forcing pump or equivalent device of
the apparatus of a registering mechanism, whereby the volume forced
into the carburetter is made to indicate the quantity of gas produced.
Also the combination with the carburetter of a transparent gauge 3
containing a thermometer and hydrometer, whereby the temperature and

page_text: density of the hydrocarbons being made evident, the richness of the
vaporized volume evolved therefrom, and consequently the resultant
illuminating gas may be readily and accurately known.
Also the combination with the registering pump of the apparatus of
cone pulleys or their equivalents for changing or adjusting the speed of
the same, so that the volume admitted to the carburetter may be readily
regulated to meet the conditions incurred by the temperature and density
at any given time of the hydrocarbons.
Also the combination with the carburetter of a pipe and forcing device,
whereby when required the heavier portions of the hydrocarbon, as when
crude petroleum is used, may be forced to the retort for distillation with
the vapor, charged air, or gas, passed simultaneously to the retort from
the said carburetter.
Also the construction of the carburetter with heating surfaces so
arranged as to permit the economical and efficient employment of steam
or hot air to replace to the hydrocarbon the heat rendered latent by
the vaporization, and which if not thus replaced would reduce the tempe-
rature of the liquid below that at which the charging of the air or gas
with vapor is feasible.
Also an apparatus for carrying into effect the herein-before mentioned
process in any of its modifications by means of a caloric engine, so
called, whereby the apparatus may be supplied with the requisite heat
from the motor operating the moving parts of the apparatus when such
are used, or applied to other purposes when desired. The air or gas
forcing pump and steam heating appliances essential under some cir-
cumstances being dispensed with when the aforesaid engine is adopted
for the purpose indicated.

page_text: •
Figures 5 and 6 are detached views, shewing the means whereby the
volume of gas made is accurately known and registered.
Figure 7 is a detached sectional view of a valve provided to prevent
regurgitation of the gas while in process of manufacture from one part of
the apparatus to another. ·
Figure 8 is a side view and vertical section of a modification of the
apparatus, as shewn in Figures 1 and 2; Figure 9 is a plan view and
partial horizontal section of the same.
Figure 10 is a vertical section of another modification, of which
Figure 11 is a plan view and partial horizontal section.
Figure 12 is a front clevation of a bench of retorts designed in the
practice of the Invention for use in connection with the parts repre-
sented in Figures 1 and 2, 8 and 9, 10 and 11; Figure 13 is a longitudinal
section of the same.
E
1
The carburetter A, as shewn in Figures 1, 2, 10, 11, is made in two 1
parts identical in construction, and connected together by two pipes A*
and B*, the former of which forms part of the inlet pipe D, and the latter
part of the outlet pipe C, the purpose of which is herein-after fully set
forth:
When preferred the carburetter may be made single, that is to say, 2
with but one of the parts just represented in the aforesaid Figures, as
fully shewn in Figures 7 and 8. The construction of the carburetter is
as follows:-It may be of rectangular or other suitable shape, and is
provided with a sheet metal bottom, underneath which is a steam
chamber B. From this project upward radiator tubes a closed at their 2
upper end.
At or near the top of the carburetter, as previously herein
indicated, is the outlet pipe C, leading to or connecting with a retort
constructed as indicated in Figures 12 and 13, or in any other suitable
manner. D is the inlet pipe extended downward nearly to the bottom
of the carburetter through the agency of a pipe A* forming a part of or 3
continuation of the same. E is a glass gauge similar to an ordinary
water gauge, except that it is made largo enough to contain a thermo-
meter indicated in dotted outline at 6 in Figure 4, and a hydrometer
indicated in like manner at c in the same Figure. The outer end of the
inlet pipe D is open to the atmosphere, and the said pipe is furnished at 3
any desired point between the two ends with an air pump G*, or blowing

page_text: engine or equivalent air forcing mechanism. This may be of the rotary
kind, as shewn in Figures 1, 2, 3, 10, 11, or on the reciprocating system,
as represented in Figures 8 and 9. Arranged in suitable relation to this
forcing pump or equivalent device. is a registering apparatus F, with
the usual index fingers and dials,. and which being of well known
character and construction needs no particular description here. This
register is actuated by ratchet wheel operation by a paul or lever d
attached to an eccentric e, provided on the rotating shaft g of the pump,
or when a reciprocating pump is used, as indicated in Figures 5, 8,
and 9, by a paul, lever, or like device attached to the arm a¹ provided
on the piston rod and forming part of the valve motion of the pump.
With the rotary pump there is provided parallel to its shaft g a counter-
shaft h, and on the two is arranged a system of conc pulleys and bands,
as shewn in Figure 3, whereby from any given speed of prime mover
the speed of the pump may be regulated on occasion, as herein-after
explained.
The carburetter is also provided with a pipe G, the arrangement and
function of which are herein-after fully set forth, and which is furnished
with suitable cocks, whereby its connections with the interior of the car-
buretter may be shut off when desired.
The carburetter being filled (say to about the upper ends of the
radiator tubes a) with light petroleum, steam, or equivalent hot fluid.
is admitted to the chamber B and the radiator tubes a, the pipo G
being closed as aforesaid, and the air pump set in motion to force air
inward through the inlet pipe, the operation is as follows:-The air
issuing from the lower end of the inlet pipe bubbles up through the
hydrocarbon to the space a* above the same, and in so doing becomes
charged or saturated with hydrocarbon, which it carries off in the form
of condensible vapor. From the space a* the saturated air is conveyed
through the outlet pipe C to the retort, which may be of any ordinary
or suitable construction, as shewn in Figures 12 and 13, but which is
maintained at a heat sufficient to ensure what may be termed destruc-
tive distillation of the commingled materials, which are converted
thereby into a chemical, permanent, or fixed gas of great illuminating
power.

page_text: in Figure 7, and which is arranged at any suitable point on the aforesaid
pipe. Inasmuch as the rapid vaporization of the hydrocarbons by the air
or gases rendered latent a great quantity of heat, which if not replaced
would soon reduce the temperature so low as to effectually prevent
further volatilization, it is necessary to replace the heat thus rendered
latent, which is done by the agency of the steam chamber B and its
radiator pipes a, which diffuse the requisite amount of warmth through
the bulk of hydrocarbons in the carburetter, steam (or in lieu thereof
hot air or other heated fluid medium) being admitted to the aforesaid
chamber through suitably provided cocks.
As the readiness with which the hydrocarbon is absorbed by the air or
gases is directly dependent upon the density and temperature of the
hydrocarbons, it follows that the hydrometer and thermometer in the
glass gauge E afford convenient and accurate means of ascertaining the
extent to which carburation occurs, and consequently the richness or :
candle power of the illuminating gas produced.
The volume of gas being directly.dependent upon the volume of air or
gases introduced, the known capacity and registered revolutions or
strokes of the forcing pump enable the quantity of air or gases, and
consequently the volume of improved gas to be recorded by the index
fingers and dials of the registering mechanism F.
By substituting in the place of atmospheric air coal gas made from
inferior coals, and practically worthless for illumination, such gas will be
enriched and converted into a gas of high candle power, and furthermore
in those cases where hydrogen or oxygen gas is available for the purpose
the same may be substituted in the place of air (or of inferior coal gas as last
stated), and a rich illuminating gas thereby obtained, and moreover it is
designed to include within the general scope of this Invention the same
or analogous employment of any gascous or acriform body, which by
saturation with hydrocarbon vapor and subsequent treatment by heat a
will produce a gas of rich quality or high candle power.
For the use as a carburetting agent of heavy or crude petroleum,
instead of naphtha or light hydrocarbons, as previously herein set forth,
the apparatus is provided as shewn in Figures 1, 8, and 10, with a pipe
G extending upward from its lower part to a height somewhat greater
than the carburetter itself, bent at 6* to provide a trap, and thence

page_text: carried to the highest point or part of the outlet pipe, whence it passes
through the said pipe to the retort. Situated at any desired point in
this pipe G is a rotary or other pump B¹, operating to force the lower or
heavier portions of the liquid from the carburetter to the elevated portion
of the outlet pipe c, as indicated at a" in Figure 12, whence it flows
simultaneously with the passage to the retort of the air (or gas of inferior
quality) saturated with the lighter portions of the liquid, in the same
manner as in the other modifications of the Invention herein-before
described.
The heavier liquid on entering the retort falls upon the heated
surface of coke, broken stone, metal, or other material provided
in the usual manner, and is distilled into an incondensible gas
simultaneously with the similar treatment by heat of the vapor laḍen air
or gases entering the retort from the outlet pipe C of the carburetter,
the products from the heavy liquid aforesaid, and the vapor laden air
combining in the ultimate product an incondensible gas of great
illuminating power.
From the upper end of the pipe G is extended a return pipe C* so
arranged that any surplus forced into the pipe G will follow the return
pipe and be returned to the carburetter.
It will be understood that the illuminating gas passes from the retorts
in the usual manner through the pipe I to the hydraulic main N and
to the gasometer.
In some instances, where a caloric or hot air engine is available the
5 exhaust air from the same may be substituted for the steam used in the
heating or maintaining at the requisite temperature of the hydrocarbon
in the carburetter, and moreover the form and construction of the latter
may be modified in various ways to permit the use for this purpose of
either hot air or steam, an ordinary vertical flue boiler, under some
O conditions, being capable of advantageous use in lieu of the carburetter,
constructed specially as herein-before described.
The herein-before mentioned employment of a caloric engine is shewn
in Figures 10 and 11, in which J indicates the engine giving motion to
5 the air or gas forcing pump G*, simultaneously with which the hot
exhaust of the said engine passes through and from the pipe K into the

page_text: heating devices of the carburetter A to heat the contents thereof, as and
for the purpose herein-before fully set forth.
As shewn in the Drawings last mentioned, the carburetter is identical
with a vertical tubular steam boiler, the fire-box and tubes serving the
same purpose as the steam chamber and radiator tubes shewn in Figure 1,
the exhaust after having been thus utilized passing to the stack or
untake m
1st. The within-described method of manufacturing illuminating gas
by saturating atmospheric air or gases with the vapor of hydrocarbon,
and subsequently subjecting the same to distillation or treatment by
heat in a retort, substantially as herein set forth.
2nd. The within-described method of manufacturing illuminating gas
by the simultaneous distillation or treatment by heat in a retort of the
heavier portions of crude petroleum, and air or gases charged with vapor 1
of the lighter portions of the same, substantially as herein set forth.
3rd. The within-described method of enriching illuminating gas of
inferior quality by charging it with the vapor of a liquid hydrocarbon,
and subsequently subjecting it to distillation or treatment by heat in a
retort, substantially as herein set forth.
4th. The apparatus constituted by the forcing pump or its equivalent,
the carburetter and a suitable retort, the whole combined and operating,
substantially as and for the purpose specified.
5th. The combination with the glass gauge of the carburetter of a
thermometer and hydrometer, substantially as and for the purpose herein 2
set forth.
6th. The combination with a carburetter, constructed and operating
substantially as and for the purpose herein described, of a pipe and
forcing device for conveying the heavier portions of the hydrocarbon to
the retort simultaneously with the transmission thereto of air or gases 3
saturated with vapor from the lighter portions of the said hydrocarbons,
substantially as set forth.
7th The combination
41
1115

page_text: herein described, of a caloric engine working with a suitable exhaust
of heated air, substantially as and for the purpose herein set forth.
In witness whereof, I, the said William Henry Maitland, have here-
unto set my hand and seal, this Sixteenth day of February, One
thousand eight hundred and seventy-four.
W. H. MAITLAND. (L.S.)