The Sun.
London, England, 1854-11-21 00:00:00

INSTITUTION OF CIVIL ENGINEERS.

The business of the evening was commenced, by the
announcement of the dates of the ordinary meetings of
the session ;of appointoaent of December 19th for
the annual general Meeting, for the election of the Pre-
sident, Connell, and officers ; and of the 29th May,
1855, for the president's conversazione.
The paper read was "On the means of avoiding Smoke,
from Boiler Furnaces," by Mr. W. Woodcock.
The author commenced by-explaining the nature of
smoke as existing in furnaces, the cause of its formation,
its component gases, and the temperature at which they
became infilaminable, and then pornted out a method of
preventing the evolution of opaque Smoke, by simple and
apparently effective means. It was stated that ordinary
pa coal, under the process of destructive
gave off various volatile substances, some of which were
;
gases, such as "hydrogen," "march gas" "olefiant gas,"
" carbonic oxide," &e; these and ethers existed in the

furnace only in a gaseous state, becoming liquid or solid
when in the extr.rual air, and of such coal tar was com-
posed ; and amidst them the carbon, iu minute subdivi-
sion, was held in suspension, giving to the smoke its sable
hue. All these gases were combustible at given tempera•
tures, provided a certain amount of oxygen was present.
It was then shown that the air containing this oxygen,
if imparted to the gases, after leaving the fuel on the
bars, must be administered so as not to reduce the tem-
perature of the gales below their " flame points." , The
arguments on the chemical composition of sinoko
were enforced by extracts from a letter by Mr. Mans•
field, published in the, Mechanic's Magazine, in which

the subject was fully investigated. -
The .forarition of sm Ace, or visible carbon held in
suspension, was stated to depend entirely upon the in-
sufficiency of the supply of oxygen in the furnace, as the
heat of the furnace would cause the various gases to be
given off more rapidly than their combustion could be
supported, by the quantity of oxygen passing through
the fire-bars in the same period of time ; this evil being
much aggravated by the heat of the air as usually sup-
plied from the ordinary ash-pit, generally ranging from
200 deg. to 300 deg. Fahrenheit, and the air, at that heat,
containing less oxygen by about one-third than at the
usual atmospheric temperature, and consequently that
the combustion of the fuel to which it was supplied
must be ono-third less perfect.
The simplest means of preventing the formation of
smoke were shown to be by providing for an ample
supply of oxygen in a condensed . state, in the form of
cold air, to the fuel on the fire-bars, and by administer-
ing such further supply of oxygen to the heated gases,
. .

-
as might be necessary for their complete combustion
whildt in contact with the boiler ; this latter supply being
given at such a temperature as would insure the succes-
sive ignition of the gases as they were evolved. Thus
by establishing, •nearly perfect plim.try combustion, the
quantity of smoke evolved was shown to be reduced to
a minimum, of which no visible trace ever reached the
summit of the chimney.
The apparatus by which this desirable end was at-

tained w;.; described to consist of two parts, each being
the addition of a very simple apparatus to the ordinary
boiler furnace. The first of these was a double set of

iron bar, lying horizontally in the direction of their

length, parallel io each other, immediately beneath the
grate in the iish-pit. Each bet of bars resembled alrene-
tia.n blind in its arrangement, the bars being inclined at an
angle of 45 deg. to the horizon in the direction of their
width. The bars of the two sets were thus inclined in
opposite directions, and being so close together that a
vertical straight line could not pass between any adja-
cent pair of them ; yet far enough apart to allow all
cinders to fall freely through, and the air to pass freely
upwards to the fire. The bars were of the same length
as the grate, se as to extend from front to back. It
would be perceived, that the effect of this arrangement
must be to screen the ash-pit completely from the heat
radiated directly downwards from the grate, and so that
scarcely any would pass through by reflezion. In fact,
not a ray of heat could reach the ash-pit from the fur-
uace, without suffering four reflexions from rough iron
surfaces, which would leave a mere shadow of a ray
for further progress.
Thus a large quantity of heat, which otherwise would
be radiated out of the furnace into the ash-pit, thence
reflected, and so lost, was saved fur the boiler. The
ash-pit, also, was only slightly heated by the cinders
which fell through ; and this source of heat might be
reduced to any extent by frequently removing the rub-
bish from the pit. Another consequence was, that the
air passing from below through the grate, not being
heated in the ash-pit, entered the fire cold, and therefore
not, as it did from ordinary ash-pits, in a rarefied con-
dition. By its coolness, this air prevented to some
extent the burning of the grate-bars ; and, by its un-
rarefied state, it produced a more intense and rapid com-
bustion of the fuel after it had passed the bars.
Another part of the contrivance was more especially
the smoke-burning apparatus. It consisted of a set of
tubes, open at both ends, passing through the furnace
horizontally from front to back, and terminating within
the wall of the front of the bridge, with valves to regu-
late the access of air into the tubes. The fire-
bridge differed importantly from that of an ordinary
furnace. It was hollow ; and was divided into two
parts, the larger of which stood up from below ; the
other, which was shallower, was in contact with the boiler.
Between them all the products of combustion passed from
the furnace. The two parts communicated with each
other by channels at the sides, and thus formed together
an annular. chatnber. The tubes before mentioned entered
the front wall of this chamber, and thus established a
communication between its interior and the outer air.
The back wall, or plate, both of the upper and of the
lower part of this chamber, or bridge being perforated
with numeras holes, opening from the interior of the
bridge to the space beyond it, established a direct com-
munication between the outer air and the throat of the
flue. There was a second salid bridge beyond the first,
descending from the upper side of the flue ; this, by in-
terrupting the direct channel through that part of the
passage, retarded the flow of the smoke and gases, and
caused their perfect mixture with each other within the
space between the bridges.
The result of this arrangement was, that a current of
highly heated air, which passed through the tubes_in
and mixing with the o
the furnace, escaped at the bridge, through the
gases f per from
ora-
tions in the back wall, i
the furnace, which held the smoke in awl) n,
con-
vertee the smoke into flame.
It was
the adaptation of this ap-
paratushigh temperature of the
would be obviated, and
stoke holes and boiler rooms
to contended
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the volumes of smoke
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ee r
eeffectuallysults o f
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prevented.
i apparatus
had
been
satisfactory • that at Messrs. Meux's brewery,
there was not the'slightest appearance of opaque smoke
tveryap p
'
from the chimney, and that the money saving, resulting
not only from the more perfect combustion of the fuel,
but from the use of an inferiOr quality of coal at
a lower price, amounted to fully twenty per cent.
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intro-
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of Civil Engineers.

ME PRUSSIAN CHAMBERS are to meet on the 30th
Lastant. _

THE POLYTECaNIC INSTITUTION.-01 Eal,urday even-
ing an entirely new entertainment, consisting of a de-
scription of the rise and progress of America, illustrated
with a series of dissolving views, was exhibited for the
first time at the above interesting institution. The first
part of the entertainment commences with tilt departure
of the first emigrants from England to settle in the back
woods of America, and as it were to lay the foundation
of the great Transatlantic Republic. The lecturer intro-
duces a very lively description of the life of the early
settlers in the back woods, illustrated with a great num-
ber of very interesting views of the methods employed by
them for establishing settlements, clearing and draining
the land, building houses, farms, &c., which were inter-
spersed with some very interesting anecdotei.— The first
part concludes with the outbreak of the revolution. The
second part of the entertainment considers America as
a republic, and consists of a great number of views, with
descriptions of the principal cities and objects of
wee-
rest throughout throughout the United States. The views
beautifully executed, and the interest well maintained
throughout, and will repay a visitor an hour. The enter-
tainment adds considerably to the numerous attractions
of this highly interesting institution,