AN IMPROVED APPARATUS FOR PURIFYING THE LIGHTING GAS RESULTING FROM THE DISTILLING OF COAL
Year: 1866

page_text: LETTERS PATENT to Guillaume Charles Denis, Director of the Gasworks
of Arras, (Pas-de-Calais,) in the Empire of France, for the Invention,
of "AN IMPROVED APPARATUS FOR PURIFYING THE LIGHTING GAS RESULTING
FROM THE DISTILLING OF COAL."
Sealed the 6th October 1866, and dated the 1st May 1866.
PROVISIONAL SPECIFICATION left by the said Guillaume Charles Donis
at the Office of the Commissioners of Patents, with his Petition, on
the 1st May 1866.
I, GUILLAUME CHARLES DENIS, Director of the Gasworks of Arras, (Pas-
de-Calais,) in the Empire of France, do hereby declare the nature of the
said Invention for "AN IMPROVED APPARATUS FOR PURIFYING THE LIGHTING
GAS RESULTING FROM THE DISTILLING OF COAL," to be as follows:-
My Invention is illustrated in the accompanying Drawings, in which A,
Figure 2, shows the gas inlet consisting of a three-way pipe provided with a
turned disc, in which is mounted a valve N, Figure 5, the gas passing at X
into the first column, while the lower end of the pipe dips into the water below.
The gas is directed through the columns B', B3, B³, by closing valve N, see
Figures 2 and 5, and opening a valve O, Figures 2 and 7, the gas passing
through in the direction of the arrows. When it is desired to cut off the
washing apparatus in order to clean the columns and diaphragms herein-after
described the reverse is effected, that is, the valve N is lowered so as, to close
the orifice in the lower pipe by turning screw V₁, Figures 2 and 5, and the
other valve closed by raising the screwed stem V', which will cause the gas to

page_text: gas
pass directly through pipe T; B₁, B³, B³, Figures 1, 2, 3, 4, and 5, are vertical
columns of cast or sheet iron communicating with each other, in which water
is introduced for the purpose of cooling the gas and other volatile products,
and effecting their rapid condensation. The water introduced into the columns
through the rose heads R, Figure 2, falls in fine spray, which is further sub-
divided by falling on the wire diaphragms S, Figure 2, the water being thus
pulverized so to speak. In this condition it acts very efficaciously on the ambiant
gas, although affording no obstacle to its progress while cooling all the products
to be condensed, absorbed, or dissolved, especially the tar, napthaline, and
ammonia; C, Figures 1, 2, 4, and 7, is the escape pipe of the gas carried down
into the reservoir by the action of the plunge pipes. The gas rising to the upper
part of the reservoir escapes at C, Figures 1 and 2, which conducts the into
the air at a high elevation; if all the other hydraulic junctions are arranged at
a depth exceeding that of the immersion of the plunge pipes this pressure
will be limited in the washing and cooling apparatus, by which arrangement
a safety valve is provided, and explosions and other accidents likely to arise
from excess of pressure prevented; D, Figures 1 and 4, four openings made
in the cover of the reservoir to facilitate the cleansing of the reservoir. These
openings should be provided with closures, so as to keep them perfectly tight
during the action of the apparatus; if they are left open the gas might escape
thereat in the case of too great pressure instead of at pipe C, intended for that
purpose as before mentioned. E, Figures 1, 2, 3, 4, and 6, overflow pipe of the
reservoir; F, G, Figure 8, red line indicating the plane of the vertical section
Figure 2; H, I, Figure 2, red lines indicating the plane of the horizontal section
Figure 3; J, K, Figure 2, red line indicating the plane of the horizontal
section Figure 4. The dotted lines W, Figure 4, represent the bent forin of
the gas escape pipe, which is attached to the upper part of the column B³, see
Figure 2; this bent form of the two junctions for the inlet and outlet of the
gas
is intended to facilitate the removal of the upper horizontal pipe in order
to get at the columns to clean them, which would be difficult were it placed in
a line with the axis of said columns, see Figures 1 and 5; L, M, Figure 3, red
line showing the plane of section Figure 5, which latter serves principally to
indicate the arrangement of the valve N, Figures 2 and 5. This valve is of
double action and serves to direct the passage of the gas as before described;
O, Figures 2 and 7, valve of similar arrangement to N, except that it is single
acting. The section, Figure 7, shows the valve O in the opened position
during the action of the washing apparatus. As before explained the hand
wheel V is turned so as to close the valve when it is desired to cut off the
columns, in the latter case the ends of the screwed rods on which the hand

page_text: wheels V1, V2, are mounted should be the reverse of the positions shown in
Figure 2, that is, the stem of V' should be lowered and V raised. P, Figures 2
and 5, pipe for conveying water to the rose heads R, Fig. 2; q, Figures 2
and 5, cock for cutting off or regulating the supply of the water; R, Figure 2,
rose heads or distributors consisting of thin copper plates pierced with small
holes, through which the water is discharged into the columns; S, Figure 2,
diaphragms in two, three, or four stages superposed at about three inches apart.
These diaphragms are composed of galvanized iron wire, of from one-fifth to an
eighth of an inch in diameter with meshes of one and a half to two inches.
These diaphragms which may be increased or diminished, if desired, serve to
subdivide the water by causing it to separate in all directions. They are
supported on projections fixed in the desired positions in the columns; T,
Figures 2 and 5, pipe for conveying the gas direct without passing through
the washing and cooling apparatus; U, Figures 1, 2, 3, 4, 5, and 6, metal
reservoir on which the water falls in spray, together with the tar and other
products of condensation; E, Figure 2, overflow pipe of the water, also
seen in separate views, Figures 3, 5, and 6. The difference of level of the
same liquid in the plunge pipes and reservoir is caused by the surrounding
gas being subjected to a pressure lowering it, say, five inches. It will be
seen by this arrangement of the apparatus that if the pressure exceeds twenty
inches equal to the depth of immersion of the plunge pipes, the gas finding a
free escape will rise into the upper part of the reservoir and escape into the
air by pipe C. The depth of immersion of the plunge pipes which
represented as twenty inches in the Drawing, may be reduced if required,.
even slightly increased, for which purpose it is simply necessary to raise or
lower the nozzle of the syphon E, Figures 2 and 6. The water level should
be regulated by the position of the nozzle, so that in case of any obstruction
in the pipes through a sudden stoppage or other accident conducing to an
excess of pressure the gas may escape into the reservoir and thence into the
atmosphere through pipe C, and not otherwise. This arrangement will infallibly
prevent those dangers to which gasworks are so often subject, from the tar or
gas returning through the retorts or barrel. V1, V2, Figures 1, 2, and 5,
hand wheels and nuts for working valves N and O; W, Figures 2 and 4,
bent pipe for conducting the gas from the washing apparatus; X, Figures 2
and 4, bent pipe for conducting the gas to the washing apparatus.
Application. This safety washing and cooling apparatus should be placed
between the barrel and the purifiers of gasworks. By placing it near the
barrel I am enabled to dispense with the long pipes and complicated apparatus,
such as at present in use. 1st, the tar and plunger reservoirs, syphon, and

page_text: apparatus serving to collect the waters and tar from the barrel; 2ndly,
the various condensing apparatus, coke columns, and other voluminous and
costly apparatus, the advantage of which is further doubtful. The present
mode of washing in still water is also very defective, and it necessitates a con-
stant pressure, more or less great, being maintained, while by these improve-
ments the gas is forced to descend into the liquid in order to bring it in contact
with the washer. When these washers act properly, that is, when the plungers
produce the desired agitation, they require an excessive amount of pressure,
and, further, whatever may be the form of plunger adopted as it is practically
impossible to prevent the gas thus acted on escaping rapidly from the liquid
in the form of bubbles, so is it also impossible to ensure a proper washing, in
fact the outside only of the bubbles are washed, while the insides pass out
without being subjected to the action of the liquid. With the object of
remedying these disadvantages, and ensuring a more perfect washing, I have
designed the improved apparatus of my Invention herein-before described,
and which I term a safety cooling and washing apparatus.
This apparatus combines in one the following advantages; it serves, 1st, to
collect the tar and waters resulting from the barrel; 2ndly, to cool, condense,
and wash the various volatile products of the distillation of coal; Srdly, it
acts as a safety valve by providing an escape for the gas in the case of an
excess of pressure. By the aid of this arrangement I not only obtain in one
apparatus the same results as now require several, but these results are
infinitely superior to those obtained by the complicated apparatus in use at
the present time in gasworks. Within a limited space my apparatus will
produce more prompt condensation and a more perfect washing, and this
without the necessity of increasing the pressure, the gases circulating without
*resistance through the water subdivided in the manner described. By simul-
taneously exposing two pieces of litinus paper reddened in acidulated water to
two currents of the gas at the inlet and outlet orifices of the apparatus, the
unwashed gas will immediately turn the paper of a blue tinge, while the red
tint of the same paper will be maintained for a length of time in the presence
of the gas after it has been washed. As regards the purification of gas by
means of slaked lime it is evident, notwithstanding the contrary opinions of some,
that it is rendered much more effectual if the gas is well washed and cooled
previously to entering the purifiers than if charged with ammonia, and while
still in a heated state. If the gas is unwashed on renewing the lime in the
purifiers, it exhales an insupportable odour, which greatly inconveniences the
workmen, who in order to avoid suffocation are obliged to withdraw every
instant for the purpose of breathing the pure air. It is also remarked that

page_text: the lime when removed instead of being of a green color remains almost
entirely white. If on the contrary the purification is preceded by a thorough
washing in my apparatus the suffocating ammoniacal odour disappears and the
purifiers may be cleaned by the workmen without inconvenience or being
obliged to leave for the object above mentioned, while the lime placed in a
precisely similar manner in the purifiers acquires a very deep green tint. If
paper treated with acetate of lead be unchanged by contact with a current of
gas thus purified, it is a proof that the purification is as perfect as possible.
The above action should be regulated according to the amount of coal to be
distilled, with an equal quantity of lime it is clear that the purification is
more perfect with my washing and cooling apparatus than with any other
methods I have tried. Notwithstanding the powerful effect of the washing it
should be remarked that the lighting power of the gas is not in the least
diminished, on the contrary, although the gas arrives in a much cooler con-
dition into the purifiers than formerly, it holds in suspension an abundance of
hydrocarburets perceptible to the eye in the form of tarry smoke, but after
having passed through the layers of lime the gas no longer contains any but
the most refined and colorless oils. I have proved by experiment that gas
produced by the distillation of coal from the north of France, when subjected
to the washing treatment herein described is much more brilliant than that
obtained by the old process of washing in still water. The differenco is
perceivable to the eye without the aid of photometric experiments. It should
be also remarked that crystals of napthaline usually form abundantly in the
purifying apparatus, and in the pipes of gasometers, of which there are no
traces to be found when adopting my improved system of treatment.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Guillaume Charles Denis in the Great Seal Patent Office on
the 31st October 1866.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GUILLAUME
CHARLES DENIS, Director of the Gasworks of Arras, (Pas-de-Calais), in the
Empire of France, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the First day of May, in the year of our Lord
One thousand eight hundred and sixty-six, in the twenty-ninth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Guillaume Charles Denis, Her special licence that I, the said Guillaume

page_text: Charles Denis, my executors, administrators, and assigns, or such others as I;
the said Guillaume Charles Denis, my executors, administrators, and assigns;
should at any time agree with, and no others, from time to time and at all
times thereafter during the term therein expressed, should and lawfully might
make, use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for "AN
IMPROVED APPARATUS FOR PURIFYING THE LIGHTING GAS RESULTING FROM THE
DISTILLING OF COAL," upon the condition (amongst others) that I, the said
Guillaume Charles Denis, my executors or administrators, by an instru-
ment 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 Guillaume Charles Denis, 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
following statement, reference being had to the Sheet of Drawings hereunto
annexed, and to the letters and figures marked thereon (that is to say):-1
My Invention refers to certain improvements in apparatus for purifying the
lighting gas produced from the distilling of coal, and it consists in a new
system of washing gas in combination with the apparatus herein-after
described, which I call "a refrigeratory safety washer," reference being had to
the annexed Drawings, wherein Fig. 1 shows a top view of my safety washer;
Fig. 2 shows in vertical elevation a sectional front view of the same, the
section being taken through the line F, G, Fig. 8; Fig. 3 shows a sectional
plan of the same through the line, H, I, Fig. 2; Fig. 4 shows a sectional
plan through the line J, K, Fig. 2; Fig. 5 shows in vertical elevation a
sectional side view of my apparatus through L, M, Fig. 3; Fig. 6 shows in
detail a spout for regulating the level; and Fig. 7 shows a section of a valve.
In all these Figures the same letters indicate the same parts.
A, Fig. 2, inlet pipe for the gas, consisting of a three-way pipe, which
carries at its upper part a suitably bored box or disc for receiving the valve N,
Fig. 5, and on the side is an elbowed flanged branch X for introducing the
gases into the first column, which is terminated by a plunge pipe. The gas
is directed to the columns B1, B2, B3, by the valve N, Figs. 2 & 5, and
that O being opened, .Figs. 2 & 7, the gas then taking the course indicated by
the arrows.
When it is desired to isolate the washers in order to clean the
columns and the wire diaphragms therein the operation is to be reversed, the

page_text: valve N is lowered down, closing the orifice of the lower pipe by the screw V¹
being turned, Figs. 2 & 5, whilst the other valve is closed by the screw V2
forcing up the rod, when the gas will pass directly through the pipe T.
B', B, B³, Figs. 1, 2, 3, 4, & 5, represent the vertical cast or sheet iron
columns communicating with one another, wherein the falling water cools the
gas and other volatile products and effects a rapid energetic condensation.
The water introduced within the columns by means of the heads or roses R,
Fig. 2, drops in a fine spray upon the wirework S, Fig. 2, which being placed
there as an obstacle against which the jets are broken determine a minute
and as it were a pulverulent division of the water, which in this state of
pulverization acts with the utmost possible efficiency on the surrounding gas
although presenting no obstacle to its passage, and cools all the products
which are to be condensed, absorbed, or dissolved, principally the tar,
naphtaline, and ammonia. C, Figs. 1, 2, 4, & 7 is an outlet pipe for the
escape of the gas in case it is carried down into the reservoir by the plunge
pipes, the gas will, on rushing to the upper part of the reservoir meet with an
outlet at pipe C, Figs. 1, 2, 4, & 7, which conveys it up above the roof. If
all the other water joints have been set at the desired depth below the
immersed depth of the plunge pipes the above action will infallably be
effected by the refrigeratory washer. The apparatus will thus in performing
the office of a safety valve fulfil the desired object, which is to prevent
explosions, fire, and other accidents caused by compression. D, Figs. 1 & 4,
are four openings made in the tank lid for cleaning purposes; these openings
are to be provided with taps or plugs, so as to keep them closed during the
working of the apparatus, for if they were left open the compressed gas would
escape through them as well as it would through the pipe C especially intended
therefor. E, Figs. 1, 2, 3, 4, & 6, represents a pipe for discharging the
overflow of the tank. The dotted lines W represent the bent or elbowed
form of the outlet branch which is at the top of the column Vs. This bent form
of both the inlet and outlet pipes is intended to set back the upper horizontal
pipe, which would impede the cleaning of the columns were it placed in a line
with the axis thereof, see Figs. 1 & 5. N, Figs. 2 & 5, double-action valve
for directing at will either upwards or downwards the manufactured gas;
O, Figs. 2 & 7, is a like but single-action valve; it is shown open at Fig. 7
during the working of the washer. As above said the crank V³ is turned to
close this valve when it is desired to isolate the water columns. In this case
the end of the threaded rods which pass through the hand wheels V¹ & V
assume the reverse position to that shown at Fig. 2, the rod V¹ being
depressed and that Vs raised. P, Figs. 2 & 5, represents a pipe through

page_text: which water is conveyed into the roses R; Q, Figs. 2 & 5, represent a stop-
cock by which the passage of water is either cut off or regulated; R, Fig. 2,
represents the roses, which are like those of a watering pot; they are made of
thin copper plates pierced with small holes, through which the water passes
into the apparatus; S, Fig. 2, shows the wirework diaphragms formed of
two, three, or four rows, superposed about 3 inches (or 8 centimetres)
from one another. Each diaphragm is made of galvanized wire of about
of an inch (4 or 5 millimetres diameter) and forming squares of about 2 inches
on each internal side. The rows of each set of wires are arranged cross-
wise, as shown at Figs. 8, 9, 10, and 11, and as will be explained hereafter.
These sets, the number of which may be increased or diminished according to
requirements, form as it were obstacles, striking against which the water is
extremely subdivided and made to sprinkle in every direction; there are
formed rapidly solid crystallizations against said obstacles, and if, for instance,
the metallic squares were four times smaller I presume they would soon be
obstructed and form a solid plug through which the gas could not pass. To
obviate this I have therefore disposed my sets as follows, giving each square
three inches on each side:-The second row is so set at about 4 inches beneath
the first one that the intersecting point of each square above will correspond
in the vertical projection to the centre of each square in the next row below,
and so forth. From such arrangement it ensues that with a set of four rows,
cach of which is formed of squares as above, the obstacle presented to the
passage of the water to divide it will be the same as if one single row was
used with squares 16 times smaller, and there will be no obstructions.
Fig. 8 shows a diaphragm with a single row of wires, Fig. 9 with two,
Fig. 10 with three, and Fig. 11 with four rows superposed four inches over
one another. T, Figs. 2 & 5, is a pipe intended to convey the gas directly
without passing through the refrigeratory washer. U, Figs. 1, 2, 3, 4, 5,
& 6, is a metal tank into which drops the washing water together with the
tar and the other products of condensation. The discharge of the exceeding
liquid is made through E, shown in Fig. 2, in front view Fig. 6, and in
section Figs. 3 & 5. The difference of level of the liquid existing in the
plunge pipes or plunging parts of the columns is a testimony that the surround-
ing gas is submitted to a pressure of a little more than 6 inches (15 centi-
metres). It is obvious by the arrangement of the apparatus that should this
pressure be more than 20 inches, or the depth of the immersion of the plunge
pipes, then the gas meeting a large issue would rush up into the upper
capacity of the tank and escape through the pipe C. The immersion of the
plunge pipes may be reduced and even slightly increased by merely lowering

page_text: or raising the spout of the syphon, as at E, Figs. 2 & 6. The water level
is suitably regulated by the position of the spout, so that in case of obstruction
of the conduits, or sudden stoppage, or any other accident whereby an excess of
pressure might be brought to be, the escape of the gas may take place from the
tank and the gas be directed upwards through the issue C and not elsewhere.
From the above arrangement it results infallibly that all those dangers are
avoided to which most works are exposed in consequence of the tar or gas
returning through the retorts or washing tub.
V1, V2, Figs. 1, 2, & 5, hand wheels and nuts for working the valves
N, O; W, Fig. 4, knee pipe for the exit of the gas out of the apparatus; ✗,
Figs. 2 & 4, knee pipe for the introduction of the gas into the same. This
safety refrigeratory washer is to be placed between the washing tub and the
purifiers of coal gas works, by which position may be suppressed the long
extensions of pipes and the manifold apparatus as used heretofore, namely,
1st, the tar trough, the plunger tank, the swan neck, and apparatus for col-
lecting the waters and tar proceeding from the washing tub; 2ndly, the
various sorts of condensing apparatus, the organ stops, the radiating ventilating
condensers, the superposed plate cases, and the coke or pebble columns, all
voluminous costly apparatus, the efficiency of which is often very doubtful;
3rdly, the washers, the most used now a day is the stagnant water washer
which is not unexceptionable as it requires more or less pressure, the gas
having to be forced down into the liquid to be brought in contact therewith.
When such washers work efficiently, that is to say, when the plungers fitted
thereto do really dip in, they require an excessive pressure; moreover, what-
ever may be the form of the plunger which is adopted, as it is substantially
impossible to prevent the gas thus forced in to escape rapidly under the form
of bubbles, it is equally impossible to obtain an efficient washing, the cir-
cumference of said bubbles only is washed, whilst the internal parts will not
have undergone the action of the liquid. To obviate these inconveniences
and procure a more efficient washing I have contrived, established, and ex-
perimented upon the apparatus for which I have obtained Letters Patent, and
which I call "a safety refrigeratory washer." This apparatus by itself alone
comprises the following apparatus; it serves, 1st, to collect the tar and the
waters proceeding from the washing tub; '2ndly, to cool, condense, and wash
the various volatile products of the distilling of coal; 3rdly, it serves as a
safety valve by presenting a foreseen escape to the gas in case of an excess
of pressure, which might determine a back compression. By means of this
new arrangement which I have contrived I obtain with a single apparatus
not only results which required many apparatus, but still I dare state that

page_text: these results are more efficient than those obtained with the multiple appa-
ratus actually used in gasworks. In a rather limited space my apparatus
will procure a more rapid condensation & a more perfect washing without
even requiring an increase of pressure, the gas being made to circulate with-
out resistance through the water thus pulverized. By thus exposing simul-
taneously to two streams of gas, proceeding the one from the entrance the
other from the exit of the apparatus, two similar pieces of lithmus paper.
reddened in acidulated water, one may immediately see the unwashed gas
blue the test or reactive paper, whilst the red hue of the same reactive agent
will be long maintained in presence of the washed gas. As regards the
purifying by slacked lime it is obvious, in spite of the contrary opinion of
various authors, that such purifying is rendered more efficient when the gas
is well washed and cooled in the purifying apparatus than when it goes there
when yet hot and containing ammonia; when the gas is unwashed, you perceive
it immediately by renewing the lime in the purifyers, which emits the most
offensive odour. To avoid being suffocated the workmen are obliged to
frequently go out and breathe pure air. One may remark that the thus
removed lime instead of being green keeps almost entirely white, and if on
the contrary a good washing has preceded the purifying operation as obtained
with my apparatus, that choking ammonical odour vanishes, the workmen
will clean the apparatus without being the worse for it, nor be obliged to run
out, and the same lime placed in the purifyers in the very same manner will
assume a very intense green color; the paper soaked with acetate of lead
being not altered by a current of the purified gas it may be ascertained that
the purifying is as perfect as possible. It will suffice to proportionate these
means of action to the amount of coal to be distilled with an equal amount of
lime. It is beyond contest that the purifying operation will prove more
perfect by means of my refrigeratory washing apparatus than by any other
means ever experimented upon by me. Notwithstanding this washing power
it will be observed that the lighting power of the gas will not be impoverished
in any measure, but on the contrary although the gas comes forth into the
purifiers colder than before it still holds in suspension such an abundance of
bydrocarburets as may be perceptible to sight under the form of a tarry
smoke, but after passing through the layers of lime the gas which now con-
tains only the most subtle oils becomes completely colourless. I have ascer
tained that the gas thus washed and proceeding from the distilling of the
north of France coal is brighter than that obtained by the old washing pro-
cess with stagnant water. It will likewise be observed that naphtaline
crystals were abundantly formed in the purifying apparatus and the gas

page_text: meter conduits, whilst by my system not any vestige of them is to be seen. My
apparatus possesses great refrigeratory power. From an experiment made by
me with 43 retorts loaded with 115 bushels of coal (42 hectolitres) the
thermometer marked outside 43° Fahrenheit, in the place where the refrige-
ratory apparatus was standing 63%, in the washing water 46%, in the water
flowing away through the discharge pipe after being used 52%, in the gas
current at the entrance of the refrigerator 188, in the same current at its
exit 59, and the production of gas was 28 cubic yards or 777 cubic feet
(22 metres cubes), about 220 pounds (100 kilogrammes) of distilled coal.
My Invention is therefore grounded on a certain method of washing the gas
as described, and consists in bringing the gas in presence of a shower as it
comes out from the washing tub, and when still very hot in dividing such
liquid shower, so that all the molecules of the products of distillation be in
direct contact with that water, thus obtaining an energetic condensation
without the least pressure, in adopting afterwards the proper arrangements for
collecting the water and the condensed products, and at same time forming a
safety valve which prevents the back compression, and the whole in a restricted
space. I obtain the realization of this principle by means of the whole
arrangement which I have contrived so as to constitute the above apparatus,
the form and dimensions of which may be varied and modified.
Having thus described the nature of my Invention, and the manner in
which the same may be carried into effect, I wish it to be distinctly under-
stood that what I claim as being of my Invention is, the washing process, as
described, of lighting gas, and as effected by my apparatus so called "safety
refrigeratory washer."
In witness whereof, I, the said Guillaume Charles Denis, have hereunto
set my hand and seal, this Thirteenth day of October, in the year of
our Lord One thousand eight hundred and sixty-six.
G. CH. DENIS. (L.B.)