IMPROVEMENTS IN THE MANUFACTURE OF ILLUMINATING GAS
Year: 1867

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 5th November 1867, and dated the 10th May 1867.
PROVISIONAL SPECIFICATION left by the said George McKenzie at
the Office of the Commissioners of Patents, with his Pétition, on the
10th May 1867.
1, GEORGE MCKENZIE, of Glasgow, in the County of Lanark, North
Britain, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN THE MANUFACTURE OF ILLUMINATING GAS," to be as follows, that is to
say:
This Invention has for its object the obtaining of gas of good illuminating
power from materials of comparatively low cost; and it consists in mixing
with the poor gas obtained in the ordinary way from inferior bituminous coal
any desired proportion of a gas obtained from mineral oil mixed with minutely.
pulverised, coke, charcoal, anthracite, lime, pumicestone, iron, oxide of iron,
clay, or asbestos. The compound, consisting of the mineral oil mixed with
the pulverised material, is, beated in retorts as in the ordinary, manufacture of
illuminating gas, and the mixing of the gases is effected by simply allowing

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said George McKenzie in the Great Seal Patent Office on the
8th November 1867.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
MCKENZIE, 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 Tenth day of May, 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 GAS," upon the condition (amongst others) that I, the said
George McKenzie, 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.
1
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 has for its object the obtaining of permaneut gas of good
illuminating power froni'materials of comparatively low cost, and it consists in
mixing the comparatively poor gas obtained-in-the ordinary_way from inferior
bituminous coal with any desired proportion of a gas obtained from mineral
oil mixed with minutely pulverised coke, charcoal, anthracite, lime, pumice-
stone, iron, oxide of iron, clay, or asbestos.

page_text: The practical advantages of my said Invention arise from the fact that the
gas obtained from mineral oil in the manner indicated is of comparatively high
specific gravity, and is liable to lose considerably from condensation, when kept
for a short time, whereas when it is mixed with a, comparatively poorer gas
such loss from condensation does not take place, whilst the mixed gas is of a
considerably higher illuminating power than the poor gas by itself. The
pulverised material used with the oil. does not itself form gas, but serves to
retain the oil by its absorbent action, and thus preventing the gas from being
too rapidly thrown off by the heat, renders it less liable to subsequent loss by
condensation. By the term "inferior bituminous coal "I designate not only
the poorest bituminous coal that may be used for gas making, but also any
bituminous coal that is at all inferior to the richest boghead or cannel coal
used for gas making, and I would here further remark that I consider it to be
a modification of my Invention to mix the gas obtained (in the manner.
herein described) from mineral oil with the gas obtained from a mixture
of boghead or cannel coal with inferior coal, or with gases obtained separately
from coals of different qualities. The gases may be mixed in various pro-
portions according to the illuminating power required. By way of example I
may state that where gas retorts are arranged in benches of nine retorts each,
mineral oil may be used in one or perhaps two retorts of each bench and coal
in the others, the hottest retorts being selected for the oil. The mineral oil
may be mixed with the pulverised substance before putting it into the retorts,
or the oil may be injected continuously or intermittently upon the pulverised
substance when in a heated state in the retorts. If pulverised coke is used,
for example, and if the mineral oil is mixed with it before being charged into
the retort, I prefer them to be in the proportions of from thirty to fifty gallons
of oil to every ton of coke, the quantity of oil being inversely regulated by
its volatility, and in charging I prefer to fill each retort to the extent of from
one to two thirds. When the oil is injected seperately into the retort I prefer
the pulverised substance to occupy from one to two thirds of the capacity of
the retort. The oil may be injected means of one or more pipes leading
from an overhead tank or cask giving sufficient head. The mixing of the
gases may be effected by simply allowing them to mingle in the pipes or in
the same gasholder or gasholders, it is however advantageous for the inter-
mixing to be thorough and complete, and in works where gas exhausters are
used it will be useful to lead the two gases through them together. The
pulverised material may be repeatedly re-used.
Having thus particularly described my said Invention, and the manner in
which the same is to be performed, I have to state that what I believe to be

page_text: novel and original, and claim as the Invention secured to me by the herein-
before in part recited Letters Patent is, the manufacturing of a gas of good
illuminating power by mixing poor gas obtained from inferior bituminous
coal with gas obtained by heating mineral oil along with suitable minutely
pulverised materials as herein before described.
In witness whereof, I, the said George McKenzie, have hereunto set my
hand and seal, this Seventh day of November, in the year of our Lord
One thousand eight hundred and sixty-seven.
Witness;
EDMUND HUNT;
Patent Agent,
Glasgow.
GEORGE MCKENZIE. (L.S:)