IMPROVEMENTS IN THE MANUFACTURE OF ILLUMINATING GAS DISCLAIMER AND MEMORANDUM OF ALTERATION
Year: 1867

page_text: In the Matter of the Letters Patent granted to GEORGE M°KENZIE,
of Glasgow, in the County of Lanark, North Britain, for the
Invention of "IMPROVEMENTS IN THE MANUFACTURE OF ILLUMINATING
GAS," bearing date the 15th June 1867, No. 1748.
5 DISCLAIMER AND MEMORANDUM OF ALTERATION proposed to
be filed by the Patentee, the said George McKenzie, in the Great
Seal Patent Office with the Specification to which the same relates,
according to the Statute in that case made and provided.
WHEREAS since the dates of the said Letters Patent, and of the
O filing of the Specification thereof, I have been advised that certain of
the improvements are not of such public utility as at the time of filing
the said Specification I verily believed them to be; and that the term
"second improvement" applied in the said Specification to mere
variations of quantities not departing from the essential features of the
3 Invention is liable to be understood as implying a separate claim, which
I do not desire to make; therefore I desire to disclaim certain parts of

page_text: such disclaiming.
NOW KNOW YE, that I, the said George McKenzie, by and with the
leave of Her Majesty's Solicitor-General, do hereby disclaim the-following
words "or fatty" contained in the fourteenth line of page four of the said
Specification as printed by Her-Majesty's-Printers, also the same words in the
twenty-fourth and in-the-twenty-eighth-lines of the same page, also the same words
in-the-twenty-ninth line of page five,-alse all the words contained in the third
of the said Specification as printed by Hor Majesty's Printers,
and fifteenth and intervening lines of page five, also the words "as my first
"and second improvements" in the thirty-first line of page five, also all
the words following those last named on page five, and also those in the
first three lines of page six, all in the said Specification as printed by
Her Majesty's Printers; and I alter the said Specification by substituting
these words "My said present improvements consist" for the words
"One improvement consists" contained in the thirteenth line of page
four, and also by substituting the word "The" for the words "By a
"second improvement the" contained in the twenty-eighth line of page
and instead of the word "Thus" in the 32nd line of page 4, I insert the words "I recommend that," and in the same line I
insert the word "be" after the word "pulverised," and in the next line I insert the word "which after the word "oil"
and in the 34th line of the same page I strike out the word "thus;" and further, after the sentence ending with the words
"quantity required" in line 2 of page 5 of the said printed Specification I insert the words "I make no claim to the
proportions recommended as formning part of this my Invention.
four of the said Specification as printed by Her Majesty's Printers,
And in order that the effect of the present Disclaimer and Memo-
randum of Alteration may be clearly shown and understood I will
proceed to repeat the said Specification as proposed to be hereby altered,
omitting the preamble.
"NOW KNOW YE, that I, the said George McKenzie, 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 in writing, that is to say " :-
"
"
"
My said Invention relates to the manufacture of illuminating gas
by means of a combination or mixture of coal and oil. Letters Patent
relating to the said manufacture have been already granted to me, the
"said George McKenzie, dated the 15th March 1866 (No. 769), but in
"practically carrying out the Invention described in the Specification of
"the said Letters Patent some difficulty is experienced in charging the
gas compound into the retorts from inconvenience in handling, and
"from the gas being very rapidly formed, and becoming partially

page_text: "
"
<
ignited and thus wasted before the retorts can be closed; also when
"the whole of the coal is minutely pulverised the material has a
tendency to be carried into and stop up the pipes and apparatus of the
gas works unless these are well adapted to the use of the compound,
"and unless the manufacture of the gas is conducted with great care.
These difficulties are overcome or greatly diminished by my present
improvements, which also possess other advantages."
66
"
"
"
"
or fatty
A
"My said present improvements consist in first thoroughly inter-
mixing the mineral oil or any suitable oleaginous matter with only
part of the coal intended to be used with it in making gas, and
"afterwards roughly combining the mixture thus formed with the
"remainder. Thus, if thirty gallons of oil are to be used with one ton
of coal, as in the example of proportions described in my earlier
Specification herein-before referred to, then by my present Invention
"the thirty gallons of oil are thoroughly intermixed with half a ton of
"coal in a pulverised state, or as obtained by sifting or riddling, and
"the compound or mixture thus obtained is afterwards added to or
"roughly mixed with the remaining half ton of coal, the latter being
"in its ordinary state, that is to say, not pulverised. One obvious
"advantage of this process is the economy in the cost of grinding the
"coal. In mixing the pulverised coal with the oleaginous matter I
"prefer to effect the operation in the manner indicated in my earlier
Specification herein-before referred to, but it may be effected in any
"other way."
"
or fatty
or latty
^
The quantity of oleaginous matter mixed with the pulverised coal
may be varied, and the mixture thus produced may be mixed with
common coal or other coal used in gas making in such proportions
"as may be necessary to produce the quantity and quality of gas
I recommend that
required. Thus one ton of coal minutely pulverised combined
^
which
A
^
"with say, 60 to 70 gallons of oil produces a material capable of
giving gas of a very high illuminating power and of extra quantity
per ton; or thus if a material capable of giving gas of less illuminating
power and less in quantity per ton be desired, then a less quantity of
oil will be intermixed in the combination proportionate to the
"diminished illuminating power and quantity of gas desired. The
material formed by the said composition of minutely pulverised coal
and oil will for use be roughly intermixed with either the common

page_text: "bituminous coal or other gas making coals in such proportion as may
"be desired to secure gas of the illuminating power and quantity
required.
I make no claim to the proportions recommended as forming part of this my Invention."
66
"
"My improved gas compounds prepared as herein-before described
"are treated for the obtainment of illuminating gas precisely like the
"ordinary gas coal used for that purpose, that is to say, any of the
compounds is put into gas retorts of iron or fire-clay, such as are at
present in use, and the distillation or decomposition is effected in the
ordinary way, it being necessary to remark in connection therewith
merely that it is advantageous to employ a strong heat never less than
" a bright red heat, but a white heat or nearly so."
Having thus particularly described my said Invention, and the
"manner in which the same is to be performed, I have to state that I
" do not restrict myself to the precise details herein-before specified, but
"that what I believe to be novel and original, and claim as the Invention
"secured to me by the herein-before in part recited Letters Patent is,"
"The manufacturing of illuminating gas by using for that purpose a
compound or compounds of coal and oleaginous matter, such com-
pound or compounds being made substantially in the improved
"manner herein-before described."
or fatty
^
"In witness whereof, I, the said George McKenzie, have hereunto
"set my hand and seal, this Eleventh day of December, in the
year of our Lord One thousand eight hundred and sixty-seven."
" GEORGE MCKENZIE." (L.S.)
And I, the said George MºKenzie, do hereby further declare that the
above Disclaimer and Memorandum of Alteration is not nor is any part
thereof intended to extend the exclusive right granted by the said
Letters Patent, and that these Presents shall not extend the said
exclusive right in any way whatever.
In witness whereof, I, the said George M Kenzie, have hereunto
set my hand and seal, this First day of October, in the year of our
Lord One thousand eight hundred and seventy.
Witness,
EDMUND HUNT,
Patent Agent,
Glasgow.
GEORGE MACKENZIE. (L.s.)

page_text: To the Clerk of the Patents for Inventions.
I hereby grant my fiat, giving leave to the above-named George
McKenzie to file in the Great Seal Patent Office, with the Specification
Amended
to which the same relates, the above-written Disclaimer and
Memorandum of Alteration.

page_text: LETTERS PATENT to George McKenzie, of Glasgow, in the County of
Lanark, North Britain, for the Invention of "IMPROVEMENTS IN THE
MANUFACTURE OF ILLUMINATING GAS."
Sealed the 13th December 1867, and dated the 15th June 1867.
PROVISIONAL SPECIFICATION left by the said George McKenzie at
the Office of the Commissioners of Patents, with his Petition, on the
15th June 1867.
I, GEORGE MCKENZIE, of Glasgow, in the County of Lanark, North
Britain, do hereby declare the nature of the said Invention for "IMPROVEMENTS
IN THE MANUFACTURE OF ILLUMINATING GAS," to be as follows:-
This Invention relates to the manufacture of illuminating gas by means.
of a combination or mixture of coal and oil. Letters Patent relating to
the said manufacture have been already granted to the present applicant,
dated the 15th March, 1866 (No. 769); but in practically carrying out
the Invention described in the Specification of the said Letters Patent
some difficulty is experienced in charging the gas compound into the
retorts from inconvenience in handling, and from the gas being very rapidly
formed, and becoming partially ignited and thus wasted before the retorts

page_text: can be closed; also, when the whole of the coal is minutely pulverised
the material has a tendency to be carried into and stop up the pipes
and apparatus of the gas works unless these are well adapted to the use
of the compound, and unless the manufacture of the gas is conducted with
great care. These difficulties are overcome or greatly diminished by the
present improvements, which also possess other advantages.
One improvement consists in first thoroughly intermixing the mineral oil
or any suitable oleaginous or fatty matter with only part of the coal intended
to be used with it in making gas, and afterwards roughly combining the
mixture thus formed with the remainder; thus if thirty gallons of oil are to
be used with one ton of coal, as in the example of proportions described in
the earlier Specification, herein-before referred to, then by the present
Invention the thirty gallons of oil are thoroughly intermixed with half a ton
of coal in a pulverised state or as obtained by sifting or riddling, and the
compound or mixture thus obtained is afterwards added to or roughly mixed
with the remaining half ton of coal, the latter being in its ordinary state, that
is to say, not pulverised. One obvious advantage of this process is the
economy in the cost of grinding the coal.
By a second improvement the quantity of oleaginous or fatty matter mixed
with the pulverised coal may be varied, and the mixture thus produced may
be mixed with common coal or other coals used in gas-making in such pro-
portions as may be necessary to produce the quantity and quality of gas
required; thus one ton of coal minutely pulverized, combined with, say,
60 to 70 gallons of oil produces a material capable of giving gas of a very
bigh illuminating power and of extra quantity per ton; or thus, if a material
capable of giving gas of less illuminating power and less in quantity per ton
be desired, then a less quantity of oil will be intermixed in the combination
proportionate to the diminished illuminating power and quantity of gas
desired. The material formed by said composition of minutely pulverised
coal and oil will for use be roughly intermixed with either the common
bituminous coal or other gas-making coals in such proportion as may be
desired to secure gas of the illuminating power and quantity required.
By a third improvement gas obtained from these compounds when used in
retorts by themselves may be mixed with gas obtained from common coal or
from "cannel" or similar coals produced in other retorts.
By a fourth improvement when it is desired to only slightly increase the
illuminating power of gas obtained from common bituminous coal or from
such coal mixed with more or less "cannel" or similar coal, then mineral
oil or other oleaginous or fatty matter is added to or roughly mixed with the

page_text: coal without the latter being specially pulverised, but only in proportions not
exceeding fifteen gallons of the oil to every ton of coal.
By a fifth improvement about sixty pounds of common rosin is added to
any of the compounds or mixtures herein-before described or referred to in
order to increase the illuminating power, the rosin being by preference ground
with the coal.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said George McKenzie in the Great Seal Patent Office on the
18th December 1867.
TO ALL TO WHOM THESE PRESENTS SHALL COME; I, GEORGE
M KENZIE, of Glasgow, in the County of Lanark, North Britain, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fifteenth day of June, in the year of our Lord One
thousand eight hundred and sixty-seven, in the thirtieth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
George McKenzie, Her special licence that I, the said George McKenzie, my.
executors, administrators, and assigns, or such others as I, the said George
McKenzie, 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 "IMPROVEMENTS IN
THE MANUFACTURE OF ILLUMINATING GAB," upon the condition (amongst others)
that I, the said George M°Kenzie, 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 imme--
diately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said George McKenzie, 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 in writing, that is to say:-
My said Invention relates to the manufacture of illuminating gas by means
of a combination or mixture of coal and oil. Letters Patent relating to the

page_text: said manufacture have been already granted to me, the said George McKenzie,
dated the 15th March 1866 (No. 769); but in practically carrying out the
Invention described in the Specification of the said Letters Patent some
difficulty is experienced in charging the gas compound into the retorts from
inconvenience in handling, and from the gas being very rapidly formed and
becoming partially ignited, and thus wasted before the retorts can be closed;
also when the whole of the coal is minutely pulverised the material has a
tendency to be carried into and stop up the pipes and apparatus of the gas
works unless these are well adapted to the use of the compound, and unless
the manufacture of the gas is conducted with great care. These difficulties are
overcome or greatly diminished by my present improvements, which also
possess other advantages.
One improvement consists in first thoroughly intermixing the mineral oil or
any suitable oleaginous or fatty matter with only part of the coal intended to
be used with it in making gas, and afterwards roughly combining the mixture
thus formed with the remainder. Thus, if thirty gallons of oil are to be used
with one ton of coal, as in the example of proportions described in my earlier
Specification herein-before referred to, then by my present Invention the thirty
gallons of oil are thoroughly intermixed with half a ton of coal in a pulverised
state, or as obtained by sifting or riddling, and the compound or mixture thus
obtained is afterwards added to or roughly mixed with the remaining half ton
of coal, the latter being in its ordinary state, that is to say, not pulverised.
One obvious advantage of this process is the economy in the cost of grinding
the coal. In mixing the pulverised coal with the oleaginous or fatty
matter I prefer to effect the operation in the manner indicated in my
earlier Specification herein-before referred to, but it may be effected in any
other way.
By a second improvement the quantity of oleaginous or fatty matter mixed
with the pulverised coal may be varied, and the mixture thus produced may
be mixed with common coal or other coal used in gas-making in such pro-
portions as may be necessary to produce the quantity and quality of gas
required. Thus one ton of coal minutely pulverised combined with, say, 60
to 70 gallons of oil produces a material capable of giving gas of a very high
illuminating power and of extra quantity per ton; or thus, if a material
capable of giving gas of less illuminating power and less in quantity per ton
be desired, then a less quantity of oil will be intermixed in the combination
proportionate to the diminished illuminating power and quantity of gas desired.
The material formed by the said composition of minutely pulverised coal and
oil will for use be roughly intermixed with either the common bituminous coal

page_text: or other gas-making coals in such proportion as may be desired to secure gas
of the illuminating power and quantity required.
By a third improvement gas obtained from any of these compounds when
used in retorts by themselves may be mixed with gas obtained from common
coal or from "cannel" or similar coals produced in other retorts.
By a fourth improvement when it is desired to only slightly increase the
illuminating power of gas obtained from common bituminous coal, or from
such coal mixed with more or less "cannel" or similar coal, then mineral oil
or other oleaginous or fatty matter is added to or roughly mixed with the coal
without the latter being specially pulverised, but only in proportions not
exceeding fifteen gallons of the oil to every ton of coal.
By a fifth improvement about sixty pounds of common rosin are added to
every ton of any of the compounds or mixtures berein-before described or
referred to in order to increase the illuminating power, the rosin being by
preference ground with the coal.
My improved gas compounds prepared as herein-before described are treated
for the obtainment of illuminating gas precisely like the ordinary gas coal
used for that purpose, that is to say, any of the compounds is put into gas
retorts of iron or fire-clay such as are at present in use, and the distillation
or decomposition is effected in the ordinary way, it being necessary to remark
in connection therewith merely that it is advantageous to employ a strong
heat, never less than a bright red heat, but a white heat or nearly so.
Having thus particularly described my said Invention, and the manner in
which the same is to be performed, I have to state that I do not restrict
myself to the precise details herein-before specified, but that what I believe
to be novel and original, and claim as the Invention secured to me by the
herein-before in part recited Letters Patent is,-
1. The manufacturing of illuminating gas by using for that purpose a com-
pound or compounds of coal and oleaginous or fatty matter, such compound or
compounds being made substantially in the improved manner herein-before
described as my first and second improvements.
2. The manufacturing of illuminating gas by mixing gas made in the
manner referred to in the preceding claim with gas obtained from common
coai or from "cannel" or similar coals.
3. The obtaining of a slight increase in the illuminating power of gas
obtained from common bituminous coal, or from such coal mixed with more
or less "cannel" or similar coal, by adding to such coal or coals oleaginous
or fatty matter in the proportion of not more than fifteen gallons of oil to
every ton of coal.

page_text: And, 4. The adding of about sixty pounds of rosin to the ton of any of the
gas-producing compounds herein-before described in order to increase the
illuminating power.
In witness whereof, I, the said George McKenzie, have hereunto set my
hand. and seal, this Eleventh day of December, in the year of our
Lord One thousand eight hundred and sixty-seven.
GEORGE MCKENZIE. (L.B.)