The Sun.
London, England, 1862-02-26 00:00:00

SEWER VENTIL .4 710 W.

An experiment, costing about £l,OOO, has re-
' cently been made by Dr. Letheby, the medical
officer of health, and Mr. William Haywood, the
engineer to the Commissioners of Sewers, with the
Iview of testing the effects of the application of
charcoal to the ventilating openings of the sewers
in the City of London. It proceeded on the theory,
maintained by eminent French and English city-
mists, that charcoal has the power of absorbing
and oxydizing the miasms of organic decomposition
when they are passed over it, with atmospheric air.
A district was selected for the experiment in the
eastern part of the city, comprising a space of about
59 acres, with abmit 1,700 houses, and 14,000 inha-
bitants, bounded by Bishopsgate-street on the west,
from Cornhill to Widegate-street ; by Middlesex-
street and Somerset-street on the east, to the city
boundary; and by the Minories and Leadenhall-
street to Cornhill on the South; the whole of these
main thoroughfares being included in the area.
This district was selected because •,:he sewers there
have but a slight fall, and the currents in them
are sluggish; because the area is densely populated,
and has more than an average proportion of resi-
dent poor; and because the thoroughfares are mostly
narrow, and are therefore disagreeably affected by
the sewer gases which issue from the ventilators.
The total length of sewers in the district is 25,587
feet, of which 2,018 feet are pines, and the remainder
are constructed of brick, varying from 3ft. high by
2ft. wide to sft, high by 3ft. wide, internal dimen-
sions. Upon this length of sewer there are 104 air-
shafts, 265 gullies, 15 flushing shafts, 4 tanks, and
26 side entrances. The whole of the sewers were
isolated as far as possible, so as to prevent air cur-
rents through thom either from or to the
adjacent pas s ilig
sewers. They were, therefore, dependent
upon their own conditions for ventilation. Two
mechanical arrangements were adopted for npply-
ing the charcoal—one beitif a large sieve ..wite-
compartments, the other a series of trays for holding
the charcoal. Wood charcoal was used, broken
into pieces the size of a filbert. The experi-
ment was commenced on the 14th of July, 1860,
and has been continued more than eighteen
months. During the summer and autumn of
1860 the temperature of the air was low and
the rainfall great. As these had an influence
in checking putrefaction and in scouring the sewers,
Messrs. Letheby and Haywood were unable in
that year to form an opinion of the efficacy of the
filters; but in 1861, when the conditions of the
atmosphere were more favourable for observation,
they were able to gather sufficient facts for a report.
They state they have satisfactorily proved the cow,
plete deodorising power of the charcoal. Not only
have there been no complaints from the public of
stenches from the ventilating gratings, but they
have proved by actual observation that the odour
of the sewer gases is not perceptible when they have
traversed the charcoal. Charcoal from the venti-
lators has been submitted to chemical exami-
nation after having been in action froth
nine to twenty - months, yielding a variety of
compounds of an exceedingly offensive odour.
Trey state that if the ventilators could be so
arranged an to keep the charcoal dry, it would
not require renewal more frequently than once
a year, but at present many of them have to be
changed about once a month. They suggest that
charcoal might be enclosed in the lower compart-
ments of the lampposts, or the ventilators placed
against the sides of the houses. They next advert
to the effect of the application of charcoal upon the
general ventilation of the sewers themselves—a
point of the highest importance. It is essential,
they say, while lessening the escape of effluvium
into the streets, that the dilution of the gases gene-
rated in the sewers should not be so lessened by the
diminished supply of air as to render the atmos-
phere of the sewers dangerous to the men who work
in them, and that the stench should not find its way
more freely or in a more concentrated state into
the interior of houses by the house drains and other-
wise than it already does. The inferences deduced
from experiments on those points are that the
currents of air in the sewers were somewhat inter-
fered with, and that the ventilation of the sewers
was not so perfect as in other cases, but the differ-
ences in repect of temperature were extremely
slight. On the other hand, there appeared to have
been no appreciable effect on the condition of the
air within the sewers, as far as the experience
and observations of workmen have gone. The
chymical condition of the internal atmosphere of
the sewers, as proved by analyses, shows a pro-
portion of 79.96 per cent. of nitrogen, 19.51 of
oxygen, and 0.53 of carbonic acid, with traces
of ammonia, marsh gas, and sulphuretted hydro-
gen. They say there is, therefore, abundance
of oxygen to maintain the functions of life. The
cost ,of fitting up the 104 ventilating shafts
was nearly £919, or at the rate of about £8
16s. Bd. per ventilator ; but, as an experiment is
necessarily more costly than an established system,
a much less sam may be taken as a fair average of
the probable expense of extending the process to
the whole city. From the experiments in question
the general conclusions of Dr. Letheby and Mr.
Haywood are, that dry charcoal in the presence of
atmospheric air is a powerful means of destroying
the mephitic gases and vapours of sewers and
house-drains; that the charcoal filters may be used
with efficacy in the course of the air channels from
the drains and closets of houses, as well as in the
ventilation of the public sewers ; that in applying
the charcoal contrivances should be used which
offer the least resistance to the free passage of the
air ; and that the situation of the filters is best
when the charcoal is protected from wet and is
easily accessible.

DEATH OF THE REV. DR. ANDRENV
naot
phidlanthro-
wßhnisEErDesidenWcee
regretr
itdog
eh-ehaer. t
ho
Hthaeckdneae
yth,
fytehs
et e d
weal yl ,k
ownolurleal ebe fame The
deceasedi c dissenting
tdeiry
had
naed,
bhtea
nßeedv Dw
wide
A andn d rhe
by his indefatigable efforts in the cause of Christian charity.
The
rieste Gazette, of the 18th, says :—" The
Prince of Wales, who has been at Venice since yesterday,
was immediately after his arrival visited on board the
vessel by the Archdukes Regnier and Joseph, and shortly
after the Prince went to the palace to pay his respects to
the Empress, and remained with her for an hour. The
Prince profits by the opportunity to see all the curiosities
of the city. He sleeps on board."

A thousand Mormons, from the three northern
countries of Europe, are just leaving for Utah, in America,
by way of Hamburg. The greater part came from Den-
mark, very many of them belonging to the well-to-do mem-
bers of the peasant class.
The taffordshirc Advertiser sa3s the name of the
Rev. H. S. Fletcher was struck out of the commission of
the peace for Staffordshire immediately upon his conduct in.
connexion with the Bileton Savings Bank becoming known
to the Lord-Lieutenant.
FRENCII ACADEMY OF SCIENCES.—At the last
sitting, M. Sainte-Claire Deville communicated a paper on
a method he bad discovered for the artificial production of
levyg©, a mineral of the zeolith family, which abounds in.
the island of Skye, also neeailirGe s methodlenarm,i ts informingofpotash,other
wf
aluminate of soda, in such proportions, that the quan-
tities of oxygen containet in the silica and alumina of these
two salts may be to each other in the ratio of two to one.
The solutions, separately introduced into a strong glass
tube, became solid at the common temperature, while the
tube, hermitically closed with the blow-pipe, is being
shaken in order to effect the mixture. On being
heated to 338 deg. Pahr., the substance is formed
into a limpid liquor, which by mere decantation
yields hexagonal crystals, similar to those of
levyne, and having the same chemical composi-
tion.—M. Troost sent in a pa, er on the chemical equivalent
of lithium. The two new metals recently found in the
ores of lithino by spectral analysis might have led to the
belief that the original determination of the equi-
valent of lithium might require correctitn. M.
Troost, therefore, undertook the task of verification, and
has found the equivalent to be 7, as announced years ago
by M. Dumas.—M. Leverrier read a note on a most singu-
lar occurrence in astronomy, viz., the disappearance of a
nebula discovered by Mr. Hind on the 11th Oct., 1852,
near
a star of the 10th magnitude. It had been remarked that
both the latter and the nebula were variablhe.
M. d'Arrest announced the astounding
had disappeared. On the 26th ult. fact
Le vterratietrheanndebyl\lia
' 12-inch M.
d:
Mul not
equatorial, find a d
tracean
Chacornac both observed the star,rtco
of the nebula, although they used
telescopes. At the samee
d
afterwards one of I. Foucawt
to be found, and M. Goldsc t the same
date, Mr. Hind himself a(rdsrcioehriiisitdaeiesdhtoashoaytoettrhtsehrernvoeeawbu:ttlaewtahsenoroyt
tohf innegb.ul
aThhiitsherto occurrencereeov