IMPROVEMENTS IN OBTAINING MOTIVE POWER
Year: 1859

page_text: LETTERS PATENT to James Anderson, of Newton, in the County of Ayr,
North Britain, for the Invention of "IMPROVEMENTS IN OBTAINING MOTIVE
POWER."
Sealed the 22nd May 1860 and dated the 7th December 1859.
PROVISIONAL SPECIFICATION left by the said James Anderson at the
Office of the Commissioners of Patents, with his Petition, on the 7th
December 1859.
I. JAMES ANDERSON, of Newton, in the County of Ayr, North Britain, do
hereby declare the nature of the said Invention of "IMPROVEMENTS IN OBTAIN-
ING MOTIVE POWER," to be as follows, that is to say:-
This Invention relates to the obtainment of motive power by the agency of
heat, and has for object the utilization of an increased proportion of the heat
generated. The improvements are susceptible of embodiment in various
modifications of apparatus, in describing some of which their nature will be
best understood.
In one modification the coal by means of which the heat is obtained is first
partially burned, and wholly distilled in a furnace or gasifier, into which the
The gas obtained consisting principally
proper quantity of air is introduced.
of carbonic oxide mixed with hydro-carbons is introduced at intervals into the
[Price 8d.]

page_text: combustion chamber of the apparatus, which in the modification being described
is the cylinder wherein the motive power is developed. The cylinder is dis-
posed vertically, and the combustion is effected beneath the piston, the under-
side of which is protected by non-conducting material. To prevent or reduce
the loss from radiation of heat laterally, and to protect the sides of the cylinder,
the piston has attached to its under edge a shield consisting of a number of
cylindrical shells concentric with the cylinder, and which on the descent of the
piston enter narrow recesses separated by similar shells. The aerial matters
between the shells being changed at every stroke, will absorb and utilize the
heat that would otherwise be lost by radiation. The combustion of the
inflammable gases received from the gasifier is effected with the aid of a
suitable quantity of atmospheric air admitted or forced into the combustion
space beneath the piston. This air before becoming mixed with the inflam-
mable gases passes through a porous medium or mass of permeable matter,
from which it takes up a quantity of heat previously deposited therein. The
inflammable gases are discharged into the combustion space beneath the
piston at or near the upper surface of the porous medium and are immediately
spread laterally over the surface of the porous medium by a deflecting plate
of fire clay or other suitable material, whereby a thorough mingling of the
inflammable gases and air is obtained. The heat due to the combustion by
expanding the mixed gases or aerial matters causes the piston to rise, and
thereby yield motive power, it is preferred however to cut off the supplies of
inflammable gas and air, on a portion of the stroke being performed, the
remainder of the stroke being completed by the continued expansion of the
gases previously admitted. On the descent of the piston the gases beneath it
pass down through the porous medium, depositing therein the whole or
greater portion of the heat remaining in them above the temperature of the
atmosphere into which they finally escape by a suitable valve.
There has now to be described what takes place on the upper side of the
piston. During the descent of the piston, air enters above it by a suitable
valve, and on the ascent of the piston this air becomes compressed, and is
forced into a reservoir, from which issue by suitable passages, the supplies for
the gasifier, and for effecting the combustion beneath the piston. To absorb
the heat rendered sensible by the compression of the air above the piston jets
of cold water are introduced in the form of spray into the compressed air, pro-
vision being made for removing the water so introduced. Or instead of this
arrangement, the water jets may be dispensed with, in which case the heat due
to compression will cause the temperature of the air in the reservoir to be
greater than that of the atmosphere, as also the heat of the underside of the

page_text: porous medium under the piston, so that the spent gases will leave it in a
comparatively heated state. To prevent the loss which would thus arise
two additional masses of porous or permeable matter may be provided, the
spent gases being passed through one mass for a certain time, whilst the
supplies of fresh air are being drawn in through the other mass, the former
When one mass is
depositing their extra heat, and the latter taking it up.
considerably heated and the other cooled, the currents through them are
reversed, the spent gases being passed through the cooled mass, and the fresh
air through the heated one.
In another modification of the apparatus the spent gases and vapours or
products of combustion are not reduced to atmospheric pressure and discharged
from beneath the piston on its descent wholly into the atmosphere, but are
conveyed by a suitable passage to the upper side of the piston, excepting a
certain quantity corresponding to the amount of fresh air supplied at each
stroke. The supplies of fresh air are introduced by means of a pump, and the
quantities of spent gases which are discharged are made to assist in actuating
the pump by their expansion down to atmospheric pressure, or their power
may be utilised by some other suitable arrangement. The gases having been
transferred to the upper side of the main piston, become compressed on its
rising, and are forced into a reservoir, whence a certain quantity is admitted
beneath the piston at each stroke; jets of water are introduced in spray above
the piston at proper periods, to absorb the heat rendered sensible by com-
pression, and it is intended that the general temperature and pressure shall be
high enough for this spray to be converted into steam, the expansive action of
which, along with that of the other gases from the reservoir will contribute
to the general mechanical effect, as the gases from the reservoir will not aid the
combustion of the fresh gases from the gasifier; the fresh air is directed up in
streams immediately round the mouth of the pipe from the gasifier, so that the
combustion may be effected before admixture with the uninflammable gases
takes place.
In another modification of the apparatus the reservoir for the uninflammable
gases and vapours is dispensed with, and the portion of these which has to be
discharged into the atmosphere at each stroke is.admitted from the under to
the upper side of the piston through a valve in the piston, itself being allowed
to expand down to the atmospheric or other pressure, and thereby aid in the
piston's descent before being finally discharged. To obtain the passage of the
gases through the porous medium alternately in opposite directions this medium
is contrived to reciprocate vertically as a piston beneath the main piston.
The shield is attached to and moves along with the porous piston, the spaces

page_text: The
between the shells communicating with the space above the porous piston.
combustion is effected in a recess beneath the porous piston, and the expansion
due to it and to the heat taken up by the gases from the porous medium
causes the main and porous pistons to rise. The pistons having reached their
highest points the main piston descends, and the valve in it is opened for a
sufficient time to allow the proper proportion of gases and vapours to pass to
its upper side. The valve being then shut, the porous piston is made to
descend as rapidly as possible, the gases beneath passing upwards through it.
and depositing in it a considerable portion of their heat. The main piston
continuing its descent compresses the gases beneath it, the heat rendered
sensible by compression being absorbed by water spray, as in the other modifi-
cations. The main piston having reached its lowest point the porous piston is
raised quickly, and the gases and vapours transferred thereby from its upper
to its under side, taking up the heat previously deposited in it.
The proper
supplies of fresh air and inflammable gas are then introduced and the operations
already described are repeated.
Amongst a number of minor modifications, of which the parts of the appa-
ratus and arrangements are susceptible, there may be mentioned the forming
of the shield of a single shell made or lined with a non-conducting material,
such as fire-clay, and the giving a tapered form to the spaces between the
shield shells and their corresponding recesses, so as to entirely exclude the
gases at the end of each down stroke. The gases from the gasifier may be
submitted to a purifying process prior to their admission into the engine,
and such process may be contrived to yield valuable marketable products.
necessary constant minute supplies of inflammable gas and air may be
admitted into the combustion chamber to prevent the entire extinction of
flame therein. If it is found desirable, a small portion of the spent gases or
vapours may be repassed through the gasifier to carry forward any excess of
heat or carbon that may arise. The porous medium and shield may be placed
in a separate vessel communicating with the engine cylinder, and the com-
bustion may be effected in such separate vessel.
lf
Other kinds of inflammable gas may be used in the improved apparatus
instead of that produced in the manner herein-before described, or the heat
may be derived from the combustion of a volatile or other oil, or from any
suitable inflammable matter in the combustion chamber within the cylinder or
in a separate vessel.
Finally, it is preferred to make the porous medium of silicious or argilaceous
matter, animal or vegetable matter being used as a core in its construction.
Thus a very suitable medium may be formed by applying clay as a dressing
.

page_text: upon cotton net,, and then hardening the clay by burning, which destroys the
cotton, leaving the burni clay full of minute interstices.
and cloth treated in this way may be combined.
Several layers of clay
SPECIFICATION
in pursuance of the conditions of the Letters Patent, filed
by the said James Anderson in the Great Seal Patent Office on the
7th June 1860.
TO ALL TO WHOM THESE PRESENTS SHALL COME, 1, JAMES
ANDERSON, of Newton, in the County of Ayr, North Britain, send greeting.
WHEREAS Her Most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Seventh day of December, in the year of our Lord
One thousand eight hundred and fifty-nine, in the twenty-third year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me
the said James Anderson, Her special licence that 1, the said James Anderson,
my executors, administrators, and assigns, or such others as I, the said James
Anderson, my executors, administrators, and or 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 IMPROVEMENTS IN OB
TAINING MOTIVE POWER." upon the condition (amongst others) that I, the said
James Anderson, 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 James Anderson, do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the fol-
lowing statement in writing, reference being had to the accompanying Draw-
ings, and to the letters and figures marked thereon, that is to say:--
My said Invention relates to the obtainment of motive power by the agency
of heat, and has for object the utilization of an increased proportion of the
heat generated. The improvements are susceptible of embodiment in various
modifications of apparatus. in describing some of which their nature will be
best explained.

page_text: And in order that the Invention may be properly understood and carried
into effect, I have hereunto appended a Sheet of explanatory Drawings,
showing examples of the application of my improvements; I would, however,
remark that in the Drawings, the various parts are disposed rather with a view
to facilitate the explanation than in the manner which may be most suitable
or convenient in practice; and that, whilst in the Drawing I have shown what
I believe to be the most suitable general arrangement of the parts for the
practical application of my Invention, I by no means restrict myself to the
precise relative proportions of such parts, as these may be considerably varied
in different cases.
The Invention comprises three general systems, having several features in
common and each susceptible of modification in its details, also sundry im-
provements embodied in such systems or to be used in carrying them out, and
more or less applicable in motive-power engines of various kinds.
Under the first system and according to one modification, the coal, by means.
of which the heat is obtained, is first partially burned and wholly distilled in a
furnace or gasifier, into which the proper quantity of air is introduced. The
gas obtained consisting principally of carbonic oxide mixed with hydro-carbons
is introduced at intervals into the combustion chamber of the apparatus, which
in the modification being described is within the cylinder wherein the motive
power is developed. The cylinder is disposed vertically, and the combustion
is effected beneath the piston, the under side of which is protected by non-
conducting material. To prevent or reduce the loss from radiation of heat
laterally, and to protect the sides of the cylinder, the piston has attached to its
under edge a shield consisting of a number of cylindrical shells concentric with
the cylinder, and which, on the descent of the piston, enter narrow recesses
separated by similar shells. The aerial matters between the shells being
partly changed at every stroke will absorb and utilise the heat that would
otherwise be lost by radiation. The combustion of the inflammable gases
received from the gasifier is effected with the aid of a suitable quantity of
atmospheric air admitted or forced into the combustion space beneath the
piston. This air, before becoming mixed with the inflammable gases, passes
through a porous medium or mass of permeable matter, from which it takes
up a quantity of heat previously deposited therein. The inflammable gases are
discharged into the combustion space beneath the piston at or near the upper
or inner surface of the porous medium, and are immediately spread laterally
over the surface of the porous medium by a deflecting plate of fire-clay or other
suitable material, whereby a thorough intermingling of the inflammable gases
and air is obtained. The heat due to the combustion causes the piston to rise

page_text: and thereby yield motive power by expanding the mixed gases or aerial
matters. In general it is preferred, however, to cut off the supplies of inflam-
mable gas and air on a portion of the stroke being performed, the remainder of
the stroke being completed by the continued expansion of the gases previously
admitted. On the descent of the piston the gases beneath it pass down through
the porous medium, depositing therein the whole or greater portion of the heat
remaining in them above the temperature of the atmosphere, into which they
finally escape by a suitable valve.
There has now to be described what takes place on the upper side of the
piston. During the descent of the piston, air enters above it by a suitable
valve, and on the ascent of the piston this air becomes compressed and is
forced into a reservoir, from which issue by suitable passages the supplies for
the gasifier and for effecting the combustion beneath the piston. To absorb
the heat rendered sensible by the compression of the air above the piston, jets
of cold water are introduced in fhe form of spray into the compressed air. pro-
vision being made for subsequently removing the water so introduced. Or,
instead of this arrangement, the water jets may be dispensed with, in which
case the heat due to compression will cause the temperature of the air in the
reservoir to be greater than that of the atmosphere, as also the heat of the
under or outer side of the porous medium under the piston, so that the spent
gases will leave it in a comparatively heated state. To prevent the loss which
would thus arise, two additional masses of porous or permeable matter may be
provided, the spent gases being passed through one mass for a certain time,
whilst the supplies of fresh air are being drawn in through the other mass; the
former depositing their extra heat and the latter taking it up. When one
mass is considerably heated and the other cooled, the currents through them
are reversed, the spent gases being passed through the cooled mass, and the
fresh air through the heated one.
Under the second system and in one modification of the apparatus the spent
gases and vapours or products of combustion are not reduced to atmospheric
pressure and discharged from beneath the piston on its descent wholly into the
atmosphere, but are conveyed by a suitable passage to the upper side of the
piston, excepting a certain quantity corresponding to the amount of fresh air
supplied at stroke. The supplies of fresh air are introduced by means of a
pump, and the quantities of spent gases which are discharged are made to
assist in actuating the pump by their expansion down to atmospheric pressure,
or their power may be utilised by some other suitable arrangement. The gases
having been transferred to the upper side of the main piston, become com-
pressed on its rising, and are forced into a reservoir, whence a certain quantity

page_text: is admitted beneath the piston at each stroke. Jets of water are introduced
in spray above the piston at proper periods to absorb the heat rendered sensible
by compression, and it is intended that the general pressure and temperature
shall be high enough for his spray to be converted into steam, the expansive
action of which, along with that of the other gases from the reservoir, will
contribute to the general mechanical effect. As the gases from the reservoir
will not aid the combustion of the fresh gases from the gasifier, the fresh air is
directed up in streams immediately round the mouth of the pipe from the
gasifier, so that the combustion may be effected before admixture with the
uninflammable gases takes place. If it is found desirable, a small portion of
the spent gases or vapours may be repassed through the gasifier to carry
forward any excess of heat or carbon that may arise.
Figure on the accompanying Sheet of Drawings is a longitudinal vertical
section of a modification of motive power engine arranged and constructed
according to my said Invention under the second system, the general features
of which have just been described. As regards the parts by which the motive
power obtained is transmitted to the machinery to be driven, this engine
resembles a common form of stationary steam engine with overhead beam A,
and fly wheel shaft B, it is, however, obvious, that these parts may be modified
in various ways. The coal employed in this instance as the source of heat is
introduced into a gasifier C. which is an iron vessel lined with fire-brick, and
which is furnished with grate bars c to support the coal. The coal may be
introduced by means of a feed apparatus, such as is shown at D, into which it
is first put, being previously reduced to pieces of a comparatively small size.
The coal is thence transferred into the gasifier C as it may be required, by
means of a screw d. A valve d¹ is provided for closing the inlet into the
gasifier C whilst coal is being put into the feeder D, and at other times the
feeder is closed to the atmosphere by the valve d², so that gas cannot escape
through the feeder.
A poker c¹ is provided for stirring the coal in the gasifier
C, this poker being passed through a stuffing box in the gasifier cover, and a
door c is provided at the bottom of the gasifier for lighting the fire, and for
the removal of ashes. The air necessary for the combustion of the coal enters
the gasifier beneath the grate bars c by the pipe E, whilst the gaseous products
leave the gasifier by the pipe F. The supply of air must be regulated so that
the heat in the gasifier may not become too intense, and so that whilst the
fuel immediately on the bars is incandescent, the greater portion above may
be comparatively cool and black, in order that the heated carbonic acid rising
from the bottom layer of coal may take up additional carbon in passing
through the upper layers, and thereby be converted into combustible carbonic

page_text: oxide, which leaves the gasifier with whatever other products of combustion
there may be. Sight holes should be provided in the gasifier for ascertaining
the state of matters inside, but in general the temperature of the gas pipe F
will be a good criterion. The pipe F conveys the gas to the combustion
chamber G situated within the main cylinder H, and beneath the main
piston h. The gas issues into the combustion chamber G through a burner g,
consisting of a perforated cone of fire-brick, and the chamber is encircled by a
wall of porous or permeable material of a nature to resist heat, and is
covered by a layer g of similar material, but of a comparatively course and
open kind. The air necessary to effect the final complete conversion of the
mixed gases enters within the cylinder by the pipe e, and first filling an
annular space e' round the combustion chamber wall g', passes through this
wall into the chamber G, taking up from the porous matter some of the heat
previously radiated or deposited thereon. The combustible gases and air after
mixing and burning in the combustion chamber G pass through the porous
cover g into the space I beneath the piston h, which last they cause to rise by
their expansive force. It is preferred to cut off the supplies of combustible
gases and air on a portion of the stroke being made. the remainder of the
stroke being due to the continued expansion of the gaseous matters beneath
the piston at the time of effecting the cut off. The bottom of the piston his
protected by a lining or cover h¹. of a material capable of resisting heat, such
as fire-brick, and to protect the sides of the cylinder H, and prevent loss of
heat by radiation, there is attached or hung to the piston h at its under outer
edge a shield, consisting of a series of cylindrical shells of thin metal, which,
on the descent of the piston h enter spaces i, separated by similar stationary
shells round the lower part of the cylinder H. It will appear on consideration,
that this shield does not reduce the effective area beneath the piston h, whilst
the change at every stroke of gaseous matters in the interstices and over the
surfaces of the shells will cause the heat radiated or deposited upon the shells
to be continually taken up again by the gaseous matters, and so utilised. On
the descent of the piston k, the gases beneath it in the space I. pass down-
wards through an annular mass i' of porous or permeable material encircling
the upper part of the combustion chamber G, and in passing through this
porous mass i. the gases deposit therein a large portion of their heat. Beneath
the porous mass there is an annular space i, by which the gases pass to the
egress pipe J, the valve of which is, of course, open during the downward
stroke of the piston. To facilitate the passage of the gases inio and out of
the spaces between the shells i and h, the former spaces are made to com-
municate at the bottom with each other, and with one or more passages, such

page_text: as the one shown at
pipe J has a branch
communicating with the annular space . The egress
leading to the air pump K, and also communicates
with a passage j leading to the upper end L of the main cylinder H, whilst
the passage has a port communicating with upper part of a second
cylinder M. At each stroke a portion of the gases from beneath the main
piston corresponding to the air admitted from the atmosphere at each stroke
(as herein-after explained), and to the amount of gases evolved from the coal.
are admitted into the upper part m of the second cylinder, a valve being
provided in the port to regulate the amount. This portion of gases expands
in the space m above the second piston m', exerting a certain amount of
mechanical force during the descent of this piston. To the under side of this
second piston m' there is attached a porous or permeable mass N of any
suitable material, such as wire gauze, and the lower part 1 of the cylinder M
is filled with cold water, in which the porous mass N is wholly immersed when
the piston m is at the bottom of its stroke. A passage O with a valve o'
extends from the upper part m of the cylinder M to the lower part, with which
last it communicates by an annular passage of extending nearly round the
cylinder, and by perforations through the side of this passage. On the ascent
of the piston m' the gases will pass from its upper to its under side, and
entering the interstices of the porous mass N, will deposit therein almost the
whole of its heat above that of the atmosphere, and become condensed. Then.
on the following descent of the piston m', the gases beneath it will become
compressed, until the pressure attained is slightly above atmospheric pressure,
when they will escape by a valve o provided for the purpose in communication
with the annular passage o2. The descent of the piston m immerses the porous
mass N in the water beneath, and this water takes up the heat deposited in
the porous mass by the gases. The water enters in as cold a state as possible
by a pipe at the bottom of the cylinder M, and a slight overflow of the
upper and hottest part of it takes place at cach down stroke through the
escape valve o. It has already been mentioned that the passage ³ com-
municates with the top of the main cylinder H. by this passage a portion of
the gases from beneath the main piston pass into the space L above it
expanding and filling this space as the piston h descends. When the piston H
next ascends. the gases above it become compressed until they attain a pressure
which enables them to open a valve p communicating with the reservoir P. A
pipe Q having a number of small branches y passed through the cover of the
main cylinder H is provided for introducing into the space L jets of water for
the purpose of absorbing the heat rendered sensible by the compression of the
If the temperature is sufficiently high this water will be converted into
gases.

page_text: steam and pass off with the gases into the reservoir P, but if the water is not
converted into steam provision must be made for removing it. The reservoir P
has an outlet pipe p' which communicates with the annular space beneath
the porous mass i¹ in the lower part of the main cylinder H, and which pipe is
provided with a valve p². This valve p is opened during the ascent, or a
portion of the ascent, of the main piston h, and admits a portion of the com-
pressed gases from the reservoir P, which portion of gasses passes upwards
through the porous mass , and takes up the heat deposited therein during
the preceding descent of the piston, becoming mixed above the porous mass i¹
with the gases entering from the combustion chamber G, and by its expansion
contributing to the general effect. The two piston rods and mare con-
nected to the beam A on the same side of its centre, and from pins r, also on
the same side, but nearer the centre of the beam, a couple of rods ¹ pass down
to work the air pump K, being jointed to a crosshead upon the piston rod r².
The pump is provided with a valve k at its upper side for admitting atmo-
spheric air, which it forces through the valve K¹ into the air pipe E already
herein referred to as conveying to the gasifier C and combustion chamber G
what is necessary for combustion. The under side of the pump communicates
by the valve with the branch
the main cylinder H. and by this passage a portion of the gases which have
already operated more or less are received into the pump K and forced into
the gasifier C to carry forward any excess of heat or carbon that may arise
therein. This portion of the gases passes by the valve into the air pipe E,
but as the valve giving admission into the cylinder H is closed at the time,
namely, during the descent of the air-pump piston, as also of the main piston h
it passes into the gasifier. A separate pipe, however, may be provided for
conveying it into the gasifier. For the purpose of actuating the various valves
(marked e, f, i, j, k, k², o, p²) a horizontal shaft S is provided to receive a
series of cams, which must be made adjustable as to their position on the shaft
in order that the times of opening and closing the several valves may be made,
such as practice indicates to be best, and in order that the power given out by
the engine may be increased or diminished according to requirement. The
cam shaft. S should rotate at the same rate as the main or fly-wheel shaft B,
from which last it may be driven by means of an intermediate shaft s, with
bevil gearing. A tube T communicating with the combustion chamber G
inside the main cylinder, is provided for the purpose of introducing a light to
ignite the gases on starting the engine; at other times this tube is closed by
a screw plug.
of the egress pipe J from the lower part of
Under the third system, for carrying out which a modification of apparatus

page_text: is in part shown in vertical section in Figure 2 on the accompanying Sheet of
Drawings, the reservoir (P) for the uninflammable or used gases and vapours
is dispensed with, and the portion of these which has to be discharged into the
atmosphere at each stroke is admitted from the under side I to the upper
side L of the piston h, through a valve. in the piston itself. being allowed to
expand above the piston, and thereby aid in the piston's descent before being
finally discharged. To obtain the passage of the gases through the porous
medium alternately in opposite directions. this medium is contrived to reci-
procate vertically as a piston beneath the main piston h, h. The shield is
attached to and moves along with the porous piston ', the spaces between the
shells communicating with the space above the porous piston. The combus-
tion is effected in a recess G beneath the porous piston, and the expansion due
to it and to the heat taken up by the gases from the porous medium causes
the main and porous pistons h. i. to rise. The pistons having reached their
highest points the main piston h descends, and the valve in it is opened for
a sufficient time to allow the proper proportion of gases and vapours to pass to
its upper side. The valve h' being then shut, the porous piston is made to
descend as rapidly as possible, the gases beneath passing upwards through it
and depositing in it a considerable portion of their heat. The main piston h
continuing its descent compresses the gases beneath it, the heat rendered sen-
sible by compression being absorbed by water spray as in the other modifi-
cations. The main piston h having reached its lowest point, the porous piston i
is raised quickly and the gases and vapours 'transferred thereby from its upper
to its under side, taking up the heat previously deposited in it. The proper
supplies of fresh air and inflammable gas are then introduced by the pipes
E, F, and valves e. f, and the operations already described are repeated. The
porous piston i' and shield h are carried by a skeleton piston U., the rod u of
which passes up through the main piston rod . made tubular for the purpose.
The water is introduced down a passage formed in the rod u.
Amongst a number of minor modifications of which the parts of the
apparatus and arrangements are susceptible, there may be mentioned the
forming of the shield of a single shell made of or lined with a non-conducting
material such as fire-clay, and the giving a tapered form to the spaces between
the shield shells and their corresponding recesses so as to entirely exclude the
gases at the end of each down stroke. The gases from the gasifier may be
If
submitted to a purifying process prior to their admission into the engine, and
such process may be contrived to yield valuable marketable products.
necessary, constant minute supplies of inflammable gas and air may be
admitted into the combustion chamber to prevent the entire extinction of

page_text: flame therein. The porous medium and shield may be placed in a separate
vessel communicating with the engine cylinder, and the combustion may be
effected in such separate vessel.
Other kinds of inflammable gas may be used in the improved apparatus
instead of that produced in the manner herein-before described, or the heal
may be derived from the combustion of a volatile or other oil, or from any
suitable inflammable matter in the combustion chamber within the cylinder
or in a separate vessel. The cylinder may be disposed in a horizontal or in a
more or less inclined position, but the vertical position is preferred. In com-
bining so as to drive one shaft, two or more sets of the apparatus represented
in Figure of the Drawings, one gasifier, and one reservoir may be contrived
to serve for the whole.
Finally, it is preferred to make the porous medium of silicious or argilaceous
matter, animal or vegatable matter being used as a core in its construction.
Thus a very suitable medium may be formed by applying clay as a dressing
upon cotton net, and then hardening the clay by burning, which destroys the
cotton, leaving the burnt clay full of minute interstices. Several layers of clay
and cloth treated in this way may be combined.
Having thus particularly described my said Invention, and the manner in
which the same is or may be used or carried into effect, I have to state that I
do not restrict myself to the precise details herein described or delineated.
and that do not claim to have invented every separate detail herein described
and delineated; but that what I consider to be novel and original, and claim
as the Invention secured to me by the herein-before in part recited Letters
Patent, is-
First, the obtaining of motive power by any of the systems herein-before
particularised, taking each as a whole.
Second, the combining of a furnace for the gasification of fuel with
apparatus for the combustion of the gases obtained, and for their expansion so
as to yield motive power, substantially as herein-before described.
Third, the placing of the porous medium for effecting the transfer of heat.
within the cylinder in which the motive power is developed, substantially as
herein-before described, whether the heat be generated within or apart from
such cylinder.
Fourth, the passing of the air on its way to aid the combustion through a
porous heat-transferring medium, and the passing of the products of combustion
through the same or a similar medium.
Fifth, the using of a shield, constructed substantially as herein-before

page_text: described, for protecting the sides of the cylinder or vessel in which the heat
is generated, and for preventing loss of heat by radiation.
Sixth, the providing to carry forward any excess of heat or carbon that may
arise in the gasifier, by passing through it a portion of the gases already passed
through the engine.
Seventh, the using for the transfer of heat of porous material obtained in
the manner herein-before explained.
In witness whereof, I, the said James Anderson, have hereunto set
my hand and seal, this Fifth day of June, in the year of our Lord
One thousand eight hundred and sixty.
Witness,
EDMUND HUNT, Patent Agent.
28, St. Enoch Square,
Glasgow.
JAMES ANDERSON. (L.S.)