CERTAIN IMPROVEMENTS IN THE MANUFACTURE OF GAS, AND IN THE APPARATUS EMPLOYED THEREIN
Year: 1845

page_text: MURDOCH'S SPECIFICATION:
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
MURDOCH, of Staple Inn, in the County of Middlesex, Mechanical Draughts-
man and Patent Agent, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Letters Patent under the Great Seal of Great Britain, bearing date at West-
minster, the Twentieth day of February, in the eighth year of Her reign, did,
for Herself, Her heirs and successors, give and grant unto me, the said James
Murdoch, Her especial licence, full power, sole privilege and authority, that
I, the said James Murdoch, my exors, adñors, and assigns, or such others
as I, the said James Murdoch, my exors, adñiors, or assigns. should at any
time agree with, and no others, from time to time and at all times during
the term of years therein expressed, should and lawfully might make, use,
exercise, and vend, within England, Wales, and the Town of Berwick-upon-
Tweed, the Invention of "CERTAIN IMPROVEMENTS IN THE MANUFACTURE OF
GAS, AND IN THE APPARATUS EMPLOYED THEREIN," communicated to me by a
certain foreigner residing abroad; in which said Letters Patent is contained
a proviso, that I, the said James Murdoch, shall cause a particular descrip-
tion of the nature of the said Invention, and in what manner the same is to
be performed, to be inrolled in Her said Majesty's High Court of Chancery
within six calendar months next and immediately after the date of the said
in part recited Letters Patent, as in and by the same, reference being there-
unto had, will more fully and at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I have
ascertained and set forth the nature of my Invention, and the manner of
carrying it into effect, in and by the following description thereof, and by
the Drawings hereunto annexed.
Figure 1 represents a front elevation of the apparatus, with a section of the
furnace and of the refrigerator; Figure 2 is a vertical section of the back end
of the apparatus; Figure 3 is a plan of the apparatus, and a horizontal
section of the brickwork of the furnace; Figure 4 is a longitudinal elevation
of the apparatus and section of the furnace; and Figure 5 is a plan of the
under side of the cover of the refrigerator. a is a retort for the distillation of
coal, set horizontally in a furnace; b, the neck of the retort, connected by the
purifying tube or retort c to the vertical retort d, in which water is distilled
and decomposed, as will be herein-after explained; c¹ is a second purifying tube
or retort, connecting the retort d with the neck 6. The tubes or retorts
c and c¹ each contain a spiral coil of iron. e is the cover of the water retort d
f, a syphon, the end of which reaches nearly to the bottom of the retort d;
g, a bridle for securing the cap of the retort d; h, arms attached by keys to
the lugs of the retort a; i, cross piece and screw for securing the door of the
retort a; j, fire bars; k, the fire-place; l, fire bricks to protect the retort from
the direct action of the flame; m, openings conducting the flames right and
left of the retorts, and heating them by reflection from the roof n of the
furnace, which is composed of fire brick; o, a vessel placed in the ash-pit, and
containing water to preserve the fire bars, and increase the flame by the steam
arising from it; q, tube conducting the gas from the-purifying retorts to the
refrigerator r, which is nearly filled with water, to cool down and condense
the gas; s, syphon to carry off the overflow of the water of condensation; t, the
pipe by which the gas passes to the gasometer; u, the cover of the refri-
gerator, having on the under side a spiral channel, along which the gas is
obliged to pass to arrive at the exit pipe t; v, the brickwork of the oven, com-
posed of common brick; a, the aperture leading to the chimney. The opera-
tion of the apparatus is as follows:-The cover of the purifying retorts is first
secured and carefully luted, and the water retort nearly filled with coke or
charcoal, and its cover secured and luted, and a fire is then kindled to bring
the retort a and the purifying retorts c, c¹, to a cherry red heat, and the retort d
to a bright red heat, and when this heat is attained the retort a is charged
with coal, and water is admitted in small quantity to the retort d, and the
action of the apparatus commences. From the coal is disengaged gas mixed
with tar, which passes into the purifying retort c. and the sulphuretted hydro-
gen is decomposed by the coil of incandescent iron, and at the same time the

page_text: tar undergoes a second distillation, and is immediately converted into gas, and
mixes with that which comes direct from the coal. The gas is now more
dense, being combined with the carbon contained in the tar. It passes along
the tube, passing round the spiral till it arrives at the water retort; here it
mixes with the hydrogen resulting from the decomposition of the water by the
incandescent coke or charcoal. This decomposition takes place at the same
time as the distillation of the coal, the water trickling in very thin streams over
the coke or charcoal gives out hydrogen, which mixes with the other gases,
and passes along with the other gases into the second purifying retort c¹,
carrying with it the carburetted vapours and volatile oils which may have
escaped decomposition, but which in passing along the incandescent iron spiral
become decomposed, and give out their carbon to the hydrogen, which thus
becomes carburetted without impoverishing the other gas. The gas, on
arriving at the end of the second purifying retort, requires only to be slightly
cooled down by passing through pure water contained in a vessel, on the
under side of the cover of which is formed a long spiral channel interrupted by
stops, so as to cause the gas to pass over a large surface of water, and occa-
sionally to pass through it. From this vessel the gas passes to the gasometer
to be stored for use. In lieu of coal, resins, schistus, oils, fats, and other
similar substances may be distilled in this apparatus; and provided the purify-
ing tubes with the spirals of iron be retained, the gas may be distilled and
purified at one operation, without the employment of a water retort.
Having thus set forth the nature of my Invention, and the manner in which
it is to be carried into effect, I proceed to state my claims.
First, I claim, as my first improvement in the manufacture of gas, the
causing the gas from coal on leaving the distillatory retort to enter a tube or
tubes containing an iron spiral, maintained at a cherry red heat, for the purpose
of purifying the gas, and for decomposing and converting into gas the tar and
essential oils which are mingled with the gas.
And, second, in combination with my first improvement, I claim the decom-
position of water by means of incandescent coke or charcoal, for the purpose of
obtaining hydrogen gas, the apparatus for this purpose being connected to the
purifying retort, and heated by the same furnace.
Third, in combination with my first improvement, I claim the employment
of any suitable apparatus for converting resinous and essential oils, schistus,
and similar substances into gas, such apparatus being connected to the
purifying retort aforesaid, and heated by the same furnace.
Fourth, I claim the general arrangement and combination of the parts of
the apparatus herein-before described.

page_text: Lastly, I claim the application of purifying retorts containing a spiral of iron
to all kinds of retorts for making gas from coal.
In witness whereof, I, the said James Murdoch, have hereunto set my
hand and seal, this Twentieth day of August, in the year of our Lord
One thousand eight hundred and forty-five.