The Sun.
London, England, 1853-02-04 00:00:00

INSTITUTION OF CIVIL ENGINEERS.

At the last meeting of the society, Mr. James Simpson,
vice-president, in the chair,
The paper was read on the " Pneumatics of Mines,"
by Mr. Joshua Richardson, M. Inst. C.E. The author,
after showing and lamenting the discrepancy existing
among the various systems of ventilation, which might
be traced to the want of good formulm for the necessary
calculations, strengthed his position by the evidence given
in the reports of the Parliamentary Committees, and of
that at South Shields in 1843. He then explained the
usual modes of calculation, and demonstrated that many
more points required to be considered than were ordina-
rily admitted to bear upon the question, and that no sound
basis of calculation could be formed on any one of the
various elements, but that the whole must be carefully
considered, after having examined each element in
detail.

The chemical constitution and properties of atmos-
pheric air were then considered, its uses in the animal
economy, its adulteration by deleterious gases, and the
compensating action piovided by nature, for restoring it
to its primitive purity.
The principles of combustion were then defined, and
calculations were given, for determining the amount of
atmospheric air required for supporting combustion and
animal respiration, and for compensating for the amount
of deterioration by perspiration. The several quantities
of air, practically required in mines, for the healthful
support of men and horses, were carefully shown, with
the modes of calculating ; allowing for the distance the
air must travel.

Then followed the analysis of the deleterious gases ex-
isting in mines ; the fire-damp, choke-damp, and after-
damp—with the quantity of atmospheric air required to
dilute these vapours, so, as to render them innocuous, or
to promote such ample ventilation as to sweep them
away from the galleries of the mines.
A clear description was then given of the " Eudiome-
ter," and of the method of using it, to discover the quan-
tity of oxygen, and the percentage of carburetted hydro-
gen, or other gases, contained in the air of any part of
a mine. The solution of chlorine in water, determining
the quantity of hydro-carbonate, or fire-damp present ;
that of green sulphate of iron, impregnated with nitrous
gas, the relative quantity of oxygen, and that of lime
water (or better, caustic potassa, or baryta), the relative
admixture of carbonic acid.
The absolute necessity for diluting the fire damp with
at least thirty times its volume of atmospheric air, and
forcing it out of the mine with rapidity, was insisted on,
and examples given of explosions occurring apparently
from the most opposite causes, still, i owever, traceable
to the same source—a deficiency of ventilation. The diagram of Dr. Clan iy's clever analysis of the fire
damp was then given and reasoned on ; and the pre-
cautions to be observed on entering a mine, after an ex-
plosion, were detailed at length, as more men were, ge-
nerally, killed by the after-darap, than by the explosion
itself.
The calculations were then given, for determining,
from the previous data, the quantity of air actually re-
quired in mine; taking into consideration the number of
men, horses, and lights, the presence of deleterious gases,
the increased temperature, the difference of barometric
pressure, and the length of the galleries through which
the air coursed.
The results were shown in tabular forms, and simple
rules were deduced for determining the quantities re-
quired, under all circumstances of varying per centage
of deleterious gases, &c.
The amount given by these rules might appear large,
but when compared with the tabular statement of the
quantity of air actually passing through twenty-four of
the principal mines in Great Britain, it was shown to be
below that allowed for the best, and even those had not
been entirely free from accidental explosions. '
The results of the investigation appeared to demon-
strate the possibility of determining the quantity of air
required in mines, under all circumstances, basing the
calculations on the premises demonstrated in the intro-
duction, and using the simple rules, whose results cor-
responded, in a remarkable degree with the best practical
observations ; and a hope was expressed that the great
simplicity and applicability of the rules would recom-
mend them to notice and experiment, until time, by
establishing their trustworthiness, should induce their
general adoption.
The discussion of the paper was adjourned, until the
meeting of Tuesday, February Bth, when the whole
evening would be devoted to the subject.

RAILWAY SHARE MARKETS.

LIVERPOOL, FBB. 3.

STOCK EXCHANGE.—The share market opened dull this
morning, but improved towards midday, and finally closed
very heavy and depressed at rather lower rates than the
closing prices of yesterday :—Caledonian, 301 ; Eastern
Counties, 124 ; Great Southern and Western, 524 ; Lanca-
shire and Yorkshire, 77; Lancaster and Carli slo (third
shares), 12A p. ; London and North-Western, 1184 ; Man-
chester, Sheffield and Lincoln, 294 ; Midland, 754 ; North
British. 8h ; North Staffordshire, 44d. ; South-Eastern
and Dover, 23A ; York and North Midland, 261.