A NEW OR IMPROVED FURNACE OR HEAT GENERATOR AND RADIATOR, TO BE USED FOR WARMING BUILDINGS OR APARTMENTS, OR FOR VARIOUS OTHER USEFUL PURPOSES."
Year: 1854

page_text: LETTERS PATENT to Gardner Chilson, of Boston, in the State of Massa-
chusetts, of the United States of America, for the Invention of." A NEW
OR IMPROVED FURNACE OR HEAT GENERATOR AND RADIATOR, TO BE USED FOR
WARMING BUILDINGS OR APARTMENTS, OR FOR VARIOUS OTHER USEFUL PURPOSES."
PROVISIONAL SPECIFICATION left by the said Gardner Chilson at the
Office of the Commissioners of Patents, with his Petition, on the 26th
May 1854.
I, GARDNER CHILSON, of Boston, in the State of Massachusetts, of the
United States of America, do hereby declare the nature of my Invention of
"A NEW OR IMPROVED FURNACE OR HEAT GENERATOR AND RADIATOR, TO BE USED
FOR WARMING BUILDINGS OR APARTMENTS, OR FOR VARIOUS OTHER USEFUL PURPOSES,"
to be as follows, it being exhibited in the accompanying Drawings, wherein
Figure 1 represents a front elevation of it; Figure 2, a side elevation of it;
Figure 3, a vertical, central, and longitudinal section of it; Figure 4 is a top
view of it; Figure 5 is a top view of the fire, chamber of it, divested of the
tapering radiators.
. In the said Drawings, A denotes the fire pot or place for burning the fuel;
B is the ash box or pit; C, a revolvable grate; D is the door of the ash-pit.
is the shaft of the grate; c' is a register opening, having a closing slide d',
the opening c' being arranged in line with the shaft 6', while the latter is in.
rear of it, as seen in Figures 1 and 3 of the Drawings. E is a flaring rim or

page_text: flange of the fire pot, and is made with a series of semi-inverted conic swells
F, F, F, &c., made to extend beyond the flare of the flange. The rim E is
provided with a groove b, b, for the reception of the radiator cones or tapering
radiators H, I, I, I, &c., the cone H being arranged between the others and
closed at its top, while they are respectively made to open into it by arched
passages 6, 6, 6, and also into a hollow annulus or ring radiator K, provided
with a discharge pipe. M is the throat or mouth-piece of the fire-place; it is
provided with an inclined door N. a¹ is a projecting ledge or flange made in
the door. c is a horizontal plate, placed across the mouth-piece and a short
distance above its bottom; f is the handle of the door; g is a stud for
supporting it at any desirable clevation.
The nature of my Invention as exhibited in the said Drawings therefore
consists as follows:-
First, it consists in the arrangement and employment with respect to a fire
pot or chamber, essentially as represented, of one or more tapering tubes or
cones formed without descending bends or flexures, and having their eduction
opening or openings made to carry off the non-combustible volatile products,
and to retain nearly, if not all, the volatile combustible products, while the
external surface or surfaces of such tube or tubes are exposed to freely radiato
heat, the same serving to generate a large amount of heat, and securing a
great economy in the consumption of fuel.
It further consists in combining with one or more such tapering tubes, made
to communicate with the fire-place, and to be capable of discharging smoke at
their upper or smaller ends, a tapering radiator, closed at top and made to
open near its base into each of the others and into the fire-place, the whole
being arranged as seen in the Drawings.
It further consists in combining with the fire pot and the exterior tapering
radiators the semi-conical swells or inverted tapering radiators attached to and
making part of the rim, the same serving not only to facilitate the entrance of
smoke and heat into the conical radiators over them, but the absorption of heat
and its radiation towards tho floor of tho chamber or room in which the
apparatus may be placed.
It further consists in arranging the feeding or fire-place door wholly within
the trunk or mouth-piece to the fire pot or place, and to incline upwards from
the bottom of the mouth-piece and inwards towards the fire chamber, and be
hinged to the top of the mouth-piece.
It further consists in combining with the said mouth-piece and the door
arranged in it, as above specified, a thin passage in the mouth-piece, and a
plate or partition extending over such passage and across the mouth-piece and

page_text: below the door, the whole being made so as to enable a thin current of air to
pass under the door and the said partition or plate, and be heated by contact
with the plate, upon which heat from the fuel when in combustion shall be
reflected by the inclined door.
It further consists in combining with the inclined door of the fire-place the
plate c, and the air passage directly under it, the small ledge or flange a', the
same being not only for the purpose of regulating the admission of air into the
passage, but of keeping it from passing under the door and over the plate c
while the ledge is below the top surface of the plate.
It further consists in the peculiar arrangement of the register hole c' with
respect to the shaft of the grate.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Gardner Chilson in the Great Seal Patent Office on the
27th October 1854.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GARDNER
CHILSON, of the State of Massachusetts, of the United States of America, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-sixth day of May, A.D. 1854, in the seven-
teenth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Gardner Chilson, Her special license that I,
the said Gardner Chilson, my executors, administrators, and assigns, or such
others as I, the said Gardner Chilson, 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 of
"A NEW OR IMPROVED FURNACE OR HEAT GENERATOR AND RADIATOR, TO BE
USED FOR WARMING BUILDINGS OR APARTMENTS, OR FOR VARIOUS OTHER USEPUL
PURPOSES," upon the condition [amongst others] that I, the said Gardner
Chilson, by an instrument in writing under my hand and seal, should par-
ticularly 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, or Office of Her Majesty's Commissioners of
Patents, within six calendar months next and immediately after the date of
the said Letters Patent.

page_text: NOW KNOW YE, that I, the said Gardner Chilson, do hereby declare
the nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
Specification, and the accompanying Drawings, letters, figures; and references
thereof :-
Of the said Drawings, Figure 1 represents a front elevation of my heat
generating and radiating apparatus or furnace; Figure 2 is a side elevation of
it; Figure 3 is a vertical, central, and longitudinal section of it; Figure 4 is
a top view of it; Figure 5. is a top view of the fire chamber of it, as such
fire. chamber appears when its pyramidal or frustro-conic heat radiators or
chambers are removed from it.
In the said Drawings, A denotes the fire pot or or place for the reception of the
fuel. It is made, generally speaking, of a depth equal to about one-fourth of its
breadth at top, and gradually diminishing in width to.its bottom, so as to give
to it the appearance of a broad flaring pan or vessel. This pan or fire pot may
be constructed of cast iron or other proper material, and if necessary it may be
thoroughly protected on its inner surface by a lining of soap-stone, fire brick,
or other suitable substance, arranged on it where the fuel would be likely to
lay in contact with it, such lining not only serving to prevent the shell of the
fire pot from becoming overheated, but also the injury that would result
thereby to air that may come in contact with its exterior surface. It also
prevents the fire pot from being destroyed by the action of the fire.
By employing a broad and shallow fire pot a greater economy of fuel results,
as unnecessary waste of fuel is avoided on account of the slowness of its com-
bustion, it being well known that when fuel is burned in deep and narrow iron
vessels, the combustion of it is faster than it is in those which are broad and
shallow, while as a general thing the advantageous exposure of the radiating
surface of the fuel is not so great in the latter as in the former. This fire pot
A rests on an iron base or ash box B, made of sufficient depth for the reception
of the ashes as they are formed, and also to admit of the revolution of a
revolvable grate C, placed at the bottom of the fire pot, as seen in the Draw-
ings. At the front of the ash box or base is a door-opening, closed by a door
D, such being for the purpose of not only regulating the draught or supply of
air under the grate, but for allowing [as circumstances may require] the
removal of the ashes, etc. from the ash pit or box.
Above the door D, and directly in line with the shaft of the grate, is a
register opening c', which has a closing slide d' applied to it. This arrange-
ment of the register opening with respect to the shaft of the grate, not only
enables the said shaft to be disposed entirely within the ash pit entrance, but

page_text: also enables the register opening to answer the purpose of not only admitting
air to the fire or fuel when required, but also of allowing a key or crank to be
introduced through it and fitted on the shaft for the object of turning or
moving the grate when necessary so to do, and thus without danger of ashes
escaping out of the ash pit, provided its door be closed.
On the top of the fire pot rests a large rim or flange E, constructed about
the height of the fire pot, and made with a series of projecting, hollow,
inverted semi-cones, as seen at F, F, F; these semi-cones being made to
extend beyond the flare of the flange, and to form so many projecting heat-
absorbing and radiating swells or extensions of the rim, while their several
bases are arranged in a horizontal plane.
Along the periphery or upper edge of the rim E and the bases of the
semi-cones there should be a groove b, b, for the reception of the radiator or
radiator cones, to be herein-after described, and for the purpose of fixing the
same thereto with a close joint, by means of sand, cement, or bolts, as the
case may require. In the before-mentioned groove rests a central cone,
frustrum, or pyramid H, and a series of any suitable number of attached
hollow pyramids, frustra, or cones I, I, I, I, &c., the Drawings representing
six of them, they being arranged around and adjoining the central conc.
These external cones together with the central cone, not only are united for
some distance above their bases, so as not only to all open into the firo
chamber over the fire pot, but so that each external cone shall enter into the
main or internal conc by a passage or archway, as seen at 62. Above the
joinings of the surrounding cones and the central conc, cach of the former
cones becomes distinct from the central cone, and constitutes a smoke passage,
which leads up into a hollow annulus or ring K, or a common smoke chamber
or radiater suitably formed.
The external cones are made to open into this chamber by apertures in
each, whose united capacities or areas should be equal to or about equal to
that of the cross section of the interior of a discharging smoke pipe L, made
to lead out of the chamber or annulus. The ring K may be provided with one
or more cleansing openings L', which may be entirely covered when the
apparatus is in use.
Attached to and extending from the broad flange E that rests on top
of the fire pot is a rectangular throat or mouth-piece M, which is made to
open into the fire-place, and-for the purpose of enabling it to be supplied with
fuel. This mouth-piece or flange is provided with an inclined door N, which
is binged at the top of the mouth-piece, and projects forwards at an angle of
about forty-five degrees with the horizontal bottom of the mouth, upon which

page_text: it rests, the same being arranged as seen in the Drawings. When the door
is closed it is supported on the bottom of the mouth-piece at or near its front
edge. The said door is provided with a projecting ledge or flange a', which
when the door is closed rests on the bottom of the mouth-piece, and passes
down by and close against a horizontal plate c, which is placed a very short
distance above the bottom of the mouth-piece and parallel to said bottom,
the open space between said plate and the bottom of the mouth-piece serving
to admit air in a thin sheet or current to the fire and over the fuel. This
thin sheet of air in passing under the plate c (which it will do when the door
is elevated a short distance) becomes highly heated by contact with it, such
plate being caused to receive heat which is reflected upon it by the fire-place
door. In this way the stratum of air becomes highly heated before and
when it reaches the gases or fuel, the heat received by it serving to greatly
facilitate the combustion of the volatile gaseous products arising from the
fuel. The ledge a' should be formed so as to work close against the front
edge of the plate c, in order to prevent, air from passing under it and over
the plate c, until it (the_ledge) is clevated entirely above-the-top-surface of
the plate. By means of the ledge the amount of air passing under the plate
can be regulated.
:
Each of the vertical sides of the mouth-piece may be provided on its inner
surface with an inclined. projecting flange or ledge m, for the door to close
against. Attached to the door, or hinged to the. front edge of it,. is a flat
handle f, such handle having several holes, notches or equivalents in it, so as
to enable the door to be elevated and supported by a stud g, or its equivalent,
extending from the top of the, mouth-piece, and introduced into any one of
the holes or notchos when the door is raised upwards..
By this arrangement of the door sundry important advantages in the opera-
tion of the furnace, stoves, etc. are obtained; there results from it the
prevention of the escape of gas or smoke out of the mouth-piece while the
fire pot is being supplied with fuel, or the door is being opened for the pur-
pose of enabling a person to examine the fire. Another advantage consists
in the facility which. this arrangement offers for regulation of the draft or
admission into the mouth-piece of air for the combustion of the gases arising
from the fuel, as the door can be adjusted at any desirable elevation, such as
may be necessary to supply the required amount of air for the combustion of
the gaseous products. By this arrangement the air adınitted is caused to pass
in direct contact with or immediately over the upper portion of the fuel in the
fire pot. Another advantage is, that when the door is nearly closed, it per-
mits but a thin stratum of air of the width of the doorway to pass under it,

page_text: which, owing to the inclination of the door, has rays of light and heat from
the fire pot reflected by the door down directly upon it, whereby the said
current of air becomes charged with heat before it comes in contact with the
gases or volatile products of combustion arising from the fuel, the same
causing such gases or volatile products of combustion to more readily ignito
and consume the carbon of the smoke than they would provided they received,
in the ordinary way of admitting air into and through the doorway, a current
of cold instead of a current of heated air.
A great economy in the consumption of fuel I have found to result from
the employment of a reflecting door, arranged and made to operato in the
above-described manner within a mouth-piece. The sides of the mouth-
piece prevent lateral disturbing currents of air from rushing upon the main
current that passes under the doorway.
In ordinary hot air furnaces, stoves, etc. there is, generally speaking, from
the fuel a very large per-centage of the volatile combustible products that
passes off into the chimney in a crude or unburned state, and is totally lost.
It will appear obvious to any scientific mind, that with the common fire
door arranged to swing on the outside of the mouth-piece of a furnace or a
stove, there must of necessity be lateral currents of cold air admitted into the
door-opening when the door is opened. These unsteady currents often cause
the smoke and more or less of the volatile products of combustion to rush
out of the upper part of the doorway and into the room or apartment in
which the furnace or stove may be; by my improved mode of arranging and
applying a door there is little or no possibility of such escape of smoke and
gases, for the inner surface of the door against which they may be thrown
being made to incline inwards, as it rises they are caused to pass upwards and
be prevented from escaping out of the doorway. Another important advantage
gained consists in having the door entirely out of the way, or protected within
the mouth-piece, it not swinging outwards into the room, as does a common
door, as it is generally applied at the mouth of a furnace. As one of the
conic frustra or cones is located directly over the door, as seen in the Drawings,
there is no convenient place in the doorway for the smoke and gases to collect
and eddy about, as they often do in the common box throat or mouth-piece,
provided with a perpendicular door applied at its outer end. The smoke from
the fire pot can pass freely up into said cone, where it is retained until much
if not all of its combustible contents are consumed, and the heat thereof
received by absorption and radiation.
By my arrangement of conical or dininishing flues the volatile products of
combustion are spread from the top of the flare of the fire pot into and against

page_text: the trunks of the surrounding cones, the large-central cone receiving a great
amount, if not nearly all, of the smoke and volatile products of combustion, and
holding them more or less suspended over the fire, so as to enable them to be
thoroughly burned; the incombustible portions of them, together with such
portions as may be combustible and have not been consumed, flow out of the
main conc and into the trunks or mouths of the surrounding cones, and
thence, after imparting heat to such cones, pass into the annular chamber or
annulus above the cone, and traversing throughout the same, escape through
its exhaust pipe, the combustible properties of the fuel being in the mean
time very thoroughly consumed.
.
By my heat generator, the volatile products of combustion, as they rise
upwards into the cones, are compressed or wedged together by the continued
taper of the cones, and are subjected by the same to the action of the rays
of light and heat from the fire pot, until their combustible properties aro
thoroughly consumed and their heat exhausted by absorbtion and radiation,
as hercin-before described.
The action of the cones in absorbing their heat is entirely different from
that of a common cylindrical pipe.or flue having vertical sides; for in such a
pipe or flue, in consequence of its sides being vertical, the smoke and ascend-
ing gases impinge to a very small extent against their inner surfaces, and
therefore there can be but little of the contact, retention, and contraction of
them, which takes place in the tapering flue, such contact, retention, and
contraction of the volatile products of combustion serving to increase the
absorption of heat from them as well as to facilitate their combustion.
From the above it will be seen that under my arrangement of the cones
over the fire pot I am enabled not only to abstract all or nearly all the beat
from the fuel and its volatile products of combustion, but to accomplish this.
without the employment of descending pipes, flues, or radiators outside of the
furnace, and in the air chamber usually surrounding it, and exposed to direct
contact with the cold air, the employment of such descending pipes or flues
tending greatly to diminish the draft.
As the heat on leaving the fire pot is nearly equally spread over all the
internal absorbing surface of the cones, there is ensured a great equality of
heat radiated, and of course a mild, agreeable, and soft warmth of the surround-
ing air, without danger of its being over heated. The peculiar arrangement of
the cones enables the external air to circulate freely between them without
injurious obstruction. By my arrangement of heating surfaces it will be seen,
that owing to their not being liable to be ever overheated, my heat generating
and radiating apparatus must be a very durable one, and also that I secure.an

page_text: pro-
immense radiating and heating surface of great power and quick action, which
any scientific mind cannot fail to see at a glance. Notwithstanding there is
this large heating surface over the fire, it is so broken up in the formation of
the conical surfaces as to prevent to a great extent, if not entirely, the
duction of the internal, inert, sluggish, or inactive heat, which is generally
caused in large cylindrical bodies or radiating drums where the heat cannot
all be made to act at once on their internal surface, the same causing a great
waste of the heat.
By my conical heat generator and radiator, not only is there an active
heating surface, but as the radiating cones are at once filled with the heated
smoke and gases, and operate to retain them over the fire, and to present
them to the direct action of the light and heat from it, or the fuel in com-
bustion, the combustible property of the smoke and gaseous products are very
thoroughly, if not entirely, burnt out of them. It will readily be seen why
this is accomplished. 1st, because of the united surrounding tapering cones
(the areas of whose openings into the annular chamber or general heat receiver
when taken together are about equal to the area of cross section of the smoke
pipe), the heated smoke and gases can escape but slowly, and consequently
they become very highly heated, and so as not only to have their combustible
properties consumed, but they (the said smoke and gases) are retained in the
cones sufficiently long to cause them to perform the part of ignited fuel, viz.,
that of generating heat for radiation, and enabling the cones to absorb and
radiate such heat with great activity.
Another great result is here developed, viz., that as these cones become filled
with light and heat, the pressure is so great that the light and heat are
reflected down upon the fuel and upon the inner surfaces of the surrounding
inverted semi-cones. The effect of this is of the utmost importance, as it not
only keeps the top of the fire bright or aids in the combustion thereof, by con-
suming the gases, but it engenders a powerful heat, which is absorbed by the
inverted semi-cones, and externally radiated and dispersed downwards around
the entire heating apparatus; so that when such apparatus is used in the hot
air chamber of a furnace or for a stove for heating purposes, the floor on which
it is supported is made comfortably warm all around the stove, within a circum-
scribing circle of several feet radius, thus securing the great and important
object of warming the floor and lower currents of air in the room, or the air
chamber of the furnace, as the case may be.
The series of inverted semi-cones and the series of upright tapering radiators
co-operate together,.so as to produce within themselves reflection and counter-
reflection of heat and light, and thereby greatly aid in the consumption of the

page_text: gaseous products of combustion, and the absorption and radiation or dissemi-
nation of heat.
This apparatus has a beautiful effect when used as a furnace for heating air
for distribution, for as so great a degree of heat is thrown off at the bases of
the inverted semi-cones, it is met and absorbed by the cold air on its entrance
into the air chamber of the furnace, and consequently the air becomes very
thoroughly charged with heat before it is discharged into the apartments to be
warmed, receiving heat to a greater extent at the bottom of the air chamber
than is the case in furnaces having no such downward radiations of heat acting
in conjunction with the fire pot.
Another important advantage secured by my Invention, and which has been
found to result in practice, is, that with it it becomes nearly, if not quite, impos-
sible to form clinkers in the coal, as the coal is consumed so slowly and steadily
that it is reduced to ashes by a natural process of consumption, as it were, which
is not favourable to the reduction of any part of it to clinker, vitrifaction and
clinker being generally caused by rapid combustion of the coal induced by any
cause, and particularly where there is a largo straight outlet to the furnace for
the smoke to rush rapidly out of or be discharged, and create a strong draught
up through the coal; such a process I have found invariably soon exhausts from
the coal those parts of it most readily combustible, and reduces the coal to slag
and clinkers. In this case the fire must soon be replenished or it will go out.
But my Invention affords almost, if not entirely, a perfect remedy for all these
evils in the common mode of burning coal.
In my apparatus there is no one largo escape pipe to produce a rapid com-
bustion by concentration of draft through the fuel, but there is a series of small
escapo tubes of a capacity less than the final discharge flue; these by their
action tend to prevent the formation of clinker.
Another important advantage secured by this Invention, that of spreading
the flame and drawing it off into the surrounding cones, so as to prevent any
one place or part of the radiator from becoming overheated, all parts of it being
very equally heated.
My improved heat generating and radiating apparatus is not only adapted
to the use of anthracite or other coal as fuel; but owing, generally speaking, to
the great breadth of the fire or fuel chamber, wood may be burned in it to good
advantage.
Another advantage is gained by my heat generator and radiator, viz., that
with it there is little or no possibility of the inner surfaces of the tapering frustra
or cones becoming injuriously coated or clogged with soot, this being owing to
the inclination of such surfaces over the fire. The impingement of the rays of

page_text: light and heat against them and the action of the same thereon is such as to
prevent the accumulation of soot in deposites of the kind set forth.
I am aware that a tapering flue, having flexures or bends or branches con-
nected by flexures, bends, or elbows, has been constructed and arranged so
that its mouth or entrance shall be directly over a fire pot or chamber, while its
eduction opening into the discharge flue has been made just or about of sufli-
cient size to freely carry off the non-combustible volatile products, and to cause
the retention in the tube of the combustible volatile products arising from the
fuel in the fire pot or chamber. Such a tapering tube so applied will be found
described in the Specification of
Patent granted to me in the United States
of America, on the Sixteenth day of September, A.D. 1851.
The said bent tapering tube differs not only in construction but considerably
in its operation from a tapering tube made without branches, bends, or flexures
arranged directly over the fuel, and provided with an eduction opening just or
about sufficient to permit to pass off' through it the non-combustible portions of
the volatile products of combustion, while it retains in the tube the combustible
portions of such products. The difference is, that in the latter tube all the
combustible gases and portions of the smoke are held suspended directly over
the fire, and are not reuioved into one or more descending flues or parts of the
bent tapering tube, where, from their remoteness from the fire, they are not
only less liable to be consumed, but do not have their non-absorbed light and
heat reflected directly downwards upon the fuel. In the employment of the
tapering tube without bend or flexure my purpose has been to avoid any of
the injurious effects of a bend or flexure, that carrying the smoke from directly
over the fire creates a downward draft of it in its course towards the eduction
opening. It will readily be seen that such a descending portion of a flue when
leading into an ascending portion of the flues operates to prevent the volatile
products in the said ascending portion from returning back upon the fire.
Experience has demonstrated, that although one long bent tubo is an excellent
radiator of heat, yet it is not so valuable as a single unbent tapering tube or a
series of such, arranged so as not only to retain the volatile products directly
over the fire and in close proximity with it, but so that their unabsorbed light
and heat may be directly reflected or thrown down upon the fuel, while the
non-combustible portions of the volatile products are allowed to escape at the
smaller end of the tube.
Another advantage results from the employment of an unbent tapering tube
of the kind above mentioned. External radiation of heat from it is not
obstructed as it is in a tapering tube, having one or more descending branches
or parts, wherein by contiguity of the ascending and descending portions more

page_text: or less obstruction to a free radiation and escape of heat results. In the bent
tapering radiator there is not that uniformity of heat in its surface that there
is in the unbent tapering tube, as the upper portions or bends of the tube
become more heated than the lower portions, and are constantly liable to
be overheated.
o
:
What therefore I claim as my improvement or Invention is, the arrangement
and employment with respect to a fire pot or chamber, essentially as described,
of one or more cones or tapering tubes without descending bends or flexures,
and having their eduction opening or openings made to carry off the non-com-
bustible volatile products, and to retain nearly, if not all, the volatile combustible
products, while the external surface or surfaces of such tube or tubes are
exposed to freely radiate beat, as described, the same serving to generate a
large amount of heat, and securing a great economy in the consumption
of fuel.
And in combination with one or more such tapering tubes made to com-
municate with the fire chamber, essentially as specified, I claim a conical or
tapering radiator, closed at top and arranged directly over the fire, and made
to open near its base into the said tapering tube or tubes, and to operate with
respect to them and the fire pot or chamber and the surrounding air or
medium to be warned or heated, substantially as specified.
I also claim the combining with the upper part of the fire pot or the rim
over the fire pot, and with the exterior cones or tapering radiators, the conical
or partially conical bases or semi-cones attached to and making part of the
rim, the same serving not only to facilitate the entrance of smoke and heat
into the conical radiators, but the absorption of heat and its radiation towards
the floor, as specified, and the reflection of heat into the tapering radiators.
I also claim the arranging the feed or fire-place door within the trunk or
mouth-piece to the fire pot or place, and so as to operate as specified.
And in combination with the mouth-piece and the door arranged within it,
as specified, I claim the passage in the mouth-piece and its plate c, for the
thin sheet or stratum of air to pass under the door [while it is wholly closed],
and said plate c, and be heated by contact with the plate before it [the said
air], reaches the fuel.
And in combination with the inclined door of the fire-place, the plate c, and
the air passage directly under it, I claim the ledge or flange a', arranged as
described, the same being not only for the purpose of regulating the admis-
sion of air into the passage, but of keeping it from passing under the door
and over the plate c, while the ledge is below the level of the top surface of the
plate.

page_text: I also claim the arrangement of the register opening [viz. in line of or
axially with respect to the shaft of the grate], in combination with the arrange-
ment of the outer end of said shaft, viz., entirely within the throat of the ash
pit or in rear of the registry plate or opening, as specified, the said arrangement
enabling me not only to dispose of the grate shaft entirely within the ash pit
mouth, [the end of said shaft when projecting from the front face of the
furnace being, generally speaking, more or less in the way, besides presenting
an appearance often disagreeable to the eye,] but to make the registry opening
answer the purpose not only of admitting air to the fire, when required, but of
enabling a person to place a key or a crank on the shaft, for the purpose of
turning or moving the grate when necessary, and this without danger of ashes
escaping out of the ash pit, provided its door be closed.
In testimony whereof, I have hereunto set my signature and seal, the
GARDNER CHILSON. (L.s.)