The Sun.
London, England, 1865-01-07 00:00:00

Christmas Lectures at the Royal Institut'on.

The fifth lecture of Dr. Frankland's Christmas
course was on the manufacture and properties of
coal gas. Having shown how coal may be distilled
in the bowl of a tobacco pipe and a gas light pro-
duced by that simple process, he proceeded to
describe how gas is manufactured on a large scale for
the lighting of towns. In this description he re-
ferred to a series of large diagrams exhibiting the
various processes through which the gas has to pass.
In the first place the coal is introduced into long
iron or earthenware retorts, intensely heated, which
are then immediately closed, and the products of the
distillation of the coal are conveyed throught up-
right tubes into a large horizontal vessel called the
hydraulic main, in which a great portion of the
tarry matter carried away by the heated gas is de-
posited. The gas then passes through a series of
perpendicular pipes that are kept cool, called con-
densers, in which the gas deposits a further quan-
tity of condensed vapour. The gas next passes, by
a continuous process into vessels called " scrubbers,"
where it is exposed to contact with a large surface
of water, which absorbs nearly all the ammonia con-
tained in the gas. From the scrubbers it is passed
through purifiers, to abstract the sulphurated hydro-
gen. The purifiers as now generally used consist
of vessels containing a number of perforated trays
one above the other, over which are strewed rust of
iron. The gas on being thus brought into contact
with the iron rust, the oxygen of the latter seizes on
the sulphur, and concretes it into a sulphur com-
pound of iron. On exposure to the air the iron be-
comes oxydised, and the same material may be
used as a purifying agent over and over again. The
gas when thus purified passes into the gasholder,
whence it is distributed through the mains and pipes
to all parts of the town. The purified gas, Dr.
Frankland stated, contains no sulphur ; but in
making that assertion he was more complimentary to
the gas companies than is warranted by a strict exa-
mination of the facts. The Metropolis Gas Act,
which recognises the difficulty of extracting all the
sulphur from gas, by permitting 20 grains of sul-
phur to remain in every 100 cubic feet of purified
gas ; and that quantity, which when burnt is suffi-
cient to impart an offensive odour to many thousand
feet of air, is generally exceeded in the gas supplied
by the London companies. The purified gas, Dr.
Frankland observed, consists of olefiant gas, fire
damp, hydrogen, carbonic oxide, and a small por-
tion of carbonic acid. The flames of the first four
gasses were exhibited, and the brilliant effect of
what is called carburetting the gas was shown by
passing hydrogen gas, which of itself gives little
light, through liquid hydrocarbons, such as naphtha,
when the flame became brilliantly luminous. This
plan has been for some time past tried in the
street lamps in the City, but there are difficulties
attending bringing it into practical operation which
have prevented it from being successful. FrOm the
fact that gas and other flames are usually burned in
atmospheric air, the former are called combustibles,

and the latter the supporters of combustion ; but
Dr. Frankland showed that the conditions may be

reversed, and that, by introducing a jet of air into
a glass vessel containing coal gas, the air seemed to
be ignited, and the gas becomes the supporter of
combustion. The general subject of the manufac-
ture of coal was illustrated by numerous other inci-
denial experiments, and towards the conclusion of
the lecture Dr Frankland described the recent ap-
plication of the explosive force of coal gas as a
motive power. He exhibited and explained the
action of Lenoir's gas-engine, whith is actuated in
that manner, and he said he should put it in opera-
tion in the next lecture.

ALARMING FIRE AT HOLLOWAY.—ShortIy before
five o'clock yesterday morning a very alarming fire broke
out on the premises belonging to the Great Northern Rail-
way Company, situate near the Holloway station. Before
the arrival of the engines the tool-house was in a blaze and
the flames were attacking the pallisading adjoining the
timber-yard, but eventually the fire was extinguished and
the timber-yard saved. Owing to the strong gale of wind
at the time it took the conductor of the escape ten minutes
to reach the fire.