The Express.
London, England, 1848-08-14 00:00:00

BRITISI[ ASSOCIATION.

At the opening of the stction on mechanical science
on Saturday,
GvrrA PERCIIA.-Mr. Whiehaw read his paper on the
various applications of gutta perches • numerous specimens of
which. in the shape of thread, cord, tubular pipes,driving:oands,
constables eaves, stick., whips, inkstands, medallions,
shields, and other ornament a, water buckets, stereotype plate',
and sundry other *etch I, both useful and ornamental, were
produced on the ciecasien. G iota percha is the concrete juice
of a large tree of the same name, abounding in Borneo.
Its introduction into this country was purely accidental, Dr.
Montgomery having transmitted the first sample of it to the
Society of Arts in 1843, at which time he (Mr. \Vf.ishaw)
was secretary to that society. The first articles of art made
of gusts pc dna in this country were laid before the Societi
of Arts in 1844, and consisted a a lathe-hand, a short lenrh
of pipe, and a bottle...wise, which he bad himself made by
hand, having caul, d the concrete substance to become suffi-
ciently plastic by immersing it in hot water. He also pro !tic• d
casts from medals, which attracted considerable atte union at
the time, and some surgical instruments were soon after
made of this new material, From 20 to 60 tons arc now
regularly imported a very month, Various experiments have
been made to ascertain its strength when mixed with other
matters, and also as to what pigments would mixed with it
without rendering it brittle ; from which it appeared,
that the only pigments that could altogether be
relied on were orange lead, rase pink, red lead,
vermilion, I)utch pink, yellow ochre, and orange chrome.
Under the Whim at , f twat and pressure, gutta percha would
spread to a n rtain extent, and more so, if mixed with nireign
matters • and all the mixtures composed of gutta perch a and
other substances which had been subjected to experiments.
except that eont .ining plumba.m, we re found to increase its
power of conducting heat; but in its pure state gutta pe rcha
was an excellent non c inductor of electricity. The best
composition for increasing the pliability of gutta percha was
that with ceoutchouc tar, and next in order that of its own
tar; and the nest material at ',resent known fur mounting
and emboeing was obmined by mixing gutta p• mho with iis
own tar and lampblack. Mr. \Vhishaw next descrilsed the
process of manutact uring gutta percha. It is reduced to pulp
by masticating 'maim's, as the materials for paper are
treated. It is purified with water, and pressed into sheets by
rollers. Its property •4 becoming plastic by immersion in
hot water is well known.

YV
St IiMAIIINH TELLORAPH.-Mr. Wishaw also exhibited
the gutta pi teha maim-acme rope or telegraph, which con•
si‘ted of a tube perforated longitudinally, tor the conveyance
of teltgrophic wire,, aid which, for the purpose of prevent.
lag its being acted upon by sea wear or marine insects, was
banded or braided round by small rope, and, being, perfectly
pliable, could easily be conveyed along the bottom of deep
water.

IMPROVEMENTS IN STEAM NAVIGATION.—Mr. J. Scott
Russell then •ernceeded to describe the improvements that
had been made in steam navigation, which he . xplained by
sppropriate diagrams. The first great improvement was in
the boilers. Formerly the flues were construe cd of crest
length, so that the smoke was kept winding round and
round, and at last was allowed to escape with difficulty. Now,
however, they had adopted the plan of getting as much fire
as possible in the shortest possible space of time, and this had
been accomplished by imitating, as nearly as they could, the
locomotive engine boiler, by having tubes of thin metal,
which would evaporate a much greater quantity of water
in the same time, that, flues of thb usual thickness. Now,
also, instead of tekiog the smoke a long dance, as formerly,
they use short flues of four or six feet in length, sod by
having a great many of them, sad of as thin metal as possible,
they heated the greatest quantity of water, and had the
additional advantage of keeping the metal cooler, and thus a
boiler of smaller extent and surface was of mach greater
efficiency with less weight of metal. The next improvement
was in the engine. The beam engine was changed for the
direct action engine, which was of various kinds • hut the
greatest change which ad been made within the last ten
years, eeneacted in the employment of greater quantities of
wrought iron in the construction of the engines, instead of
the mass of cat-iron formerly used. The paper also de.
scribed the improvements that bad been made in the
paddle-wheels, the changes in the shape of the steam-Twat
itself, and other improvements connected with this important
subje et.
GEOLOGICAL SECTION.-8011TH WALES COAL-FIELD
The subject of the great coal-field of South Wales attracted
marked retention. The geotleman selected to deliver an
address to the geologkal section on this surject was W. P.
Struve, Eeq., cis il engineer, of Seances. The subject
taken b him was the line of the mineral basin of
South Wales, extenling from New bridge, in Le
Taff Valley, to C. fyn Byrn, in Orme r, which comprises the
whole of the extensive district between the Vale of Taff
and Carmarthen Bay, including Glamorganehire and portions
of the counties of Carmarthen and Brecon, occupying an
ores of about .`,60 square mile s. This district is intersected
by six principal valleys, with canal or railway adjuncts which
convey its produce to the ports of Swansea, Ltanelly, Neath,
Cardiff, Porthcewl, and Port Trlbot. The base of the
coal measures
.in thls extensive district is carboniferous
limestooe, basin-shaped, and having a rise from its centre
towards the north and south. The lecturer, who
illustrated his views by diaerams, described specifi•
ally the various properties of different sections of this
extensive coal-field, into which it is needless I.ere to
follow him. The amount of mineral wealth appe ors to b •
enormous. The various " coal in *surer.," as they are call. d
here, exeend over 400 square miles; and the produce mcy be
guessed at, it it is calculated tr.et in one district alone one
square mile will produce 40.000,000 tons of coal, besides
8,000,000 tons of mine, and 3,000,000 tons of black hand.
The coo!, produced, of creme, vary in quality. W. ha Is
the bituminous coal, the freesAuming cost, cube, anthra-
citic colas, and meth' a, ite, of which the two former occupy
the largest portion of the coal-field. The anthracite makes
Beek rather more prominent in Carmarthenshire; end e n ar-
riving'in Pembrokeshire it is found that the whole field par-
takes of that quality.
PHoTOottApllT.—ln the Ceemical Secti in en Friday, M.
Ciaudet read a paper on " The action of the red, orange, sod
ye Low rays upon iodised and Aroma-iodised silver plates atter
they have been affected by daylight." It is well known that
is the usual Daguerr. otype process, the image impressed on
the silver plat• in the camera is invisible until the vapours of
mercury have been condensed upon it ; but it has been
ussertained that the red, orange, and yellow rays will pro-
duce the s :me effect es mercury vapour in brining out the
picture after some exposure to their influence. A plate on
which the light has impinged for a very short time may
have the picture fully developed by subsequent exposure to
red rays, and those rays considerably accelerate the pro-
c. as of taking picture a, e r that if the means of rendering an
iodised plate more sensitive by means of bromine had not
been discovered, portraits might have been taken with
iodised plates by using the accelerating power of the red
rays. A very remarkab:e distinction exists between the
ffect of the reel, orange, and yellow rays on iodised plates,
and en those that see bromo-iodised. When a plate pre-
pared with iodine alone is teken from the camera, and•
exposed to the ection of red light, the impressions made ley
the object in the locus in the camera are continued• and an
orherwise faint lecture is re teetered strong ; but when a plate
prepared with bromine in addition to iodine is similarly
treat. d, the inter, ssion of the imme is destroyed. M
Claudet stated that the effect of light on a brows indistel
plate is so instantaneous. that in the thousandth part of a
second be bad found an impre-sion produced. Mr. R. Hunt,
at the conclusion of M. Claudette paper, stated the results
of some investigations on the same subject, which had led
him to the singular conclusion that light was nothing to
do with producing Daguerreotype pictures. He
said that he had not intended to bring the subject forward
at this meeting, as he is still pursuing his investigations,
but he was induced by M. Claudette paper briefly to mention
some of the facts. He produced some images of the sun,
taken by M. Claudet during a fog, which presented the
curious appearance of a block sun in a grey coloured sky.
An image of the spectrum was also shown, in which all the
most luminous bands, the red, the orange, and the yellow,
were almost back, and the parts where the greatest
action bad taken place were in the blue and violet,
and on a large space beyond the visible rays. When
acting with cslotype paper, the effects are still more
remarkable. On exposing a sensitively prepared paper to
the spectrum, all parts of the paper were blackened,
excepting that whereon the spectrum was received, and
thus it appeared that the spectrum had effectually protected
the paper from the action of light. Mr. Hunt said he of-
fered no explanation of these facts, but he should be pre-
pared at the next meeting to enter into the subject more fully.
—Professor Grove obseived that it seemed not improbable
light produced very different effects on the visual organs of
different animals, and be conceived that what is light to the
eyes of one animal might be darkness to the eyes of another.

LIEC T. MUNRO.— This officer, who was sentenced
to 12 months' imprisonment for shooting his brother.in-law,
Lieut.-Colosel Fawcett, in a duel, will terminate on Mon-
day (this day) his term of imprisonment. It is said to be
doubtful whether he will be restored to his rank in the map

SHIPPING.

MAILS ARRITSD.—DubIin, 4 : Waterford, 2 ; Donagha-
dee, 2; French, 2; Flanders, 2; Holland, 1; Hamburg, 1.
LONDON, August 14.—Wind this day at noon, E N.H.,
fresh b and squally, with heavy TAM.
PLYMOUTH, August 13.—S. W.—Arrived, 12th : Artrmi•
sic, London, for Sydney ; Aurora, London, for Adelaide,
South Altai:she. 13th, Duke of Bedford, London, for South
Australia, with of anchor and chain. Sailed, 12th
Labe, Quebec.
Exmovrm, August 11 —Arrived: John Hall, Quebec.
PORTSMOUTH, August 13.—Arrived : Shannon, Quebec.
Sailed, 12th : Parket, Cape of Good Hope.
ABERDOVEY, August 11.—The head-board of a large
vessel, apparently not long in the water, marked " Northum-
brian," has been picked up in this bay.
CORK, August 10.—A ve,aol of a .out 480 or 500 tons,
water-logged and dtsmutel, was seen on a reef between the
Bird Rocks, 18th ult., by the Morton, arrived bore from
Dalheusla.

SUNDRILLANII, August 13.—Arrived : Cornelius, Morning
Star, and eloping, Quebec; Williams, Dalhousie 14th:
Ocean, and Wave, Quebec,. Sailed, 13th: Maria and Eliza.
beth, Quebec.

THE ANTI-CHOLERA CLAUere—The Lancet of Sa-
turday says :—" a few days the Health of Towns Bid will
doubtless he the law of the land. It will be remarkable u.
the first great sanitary enactment which this country has
ever produced; and we must wait to see it write its own
results in the registry at deaths, that being the true
place to look for the truits of a health hill. In the neat
Session, sanitary reform will again occupy a prominent
position in parliament, and it will probably be pushed in
directions which have as yet escaped the 'unitarians. The
medical profession will, in the meantime, become ac-
quainted with the practical working of this bill, and they
will, we trust, be prepared to take a far more decisive po
sition respecting this mnmentous question than they have
yet USUMed. If sanitary measures are to be what their
name implicit, they must, in the end, come to be a province of
medicine, and be administered by medical heads and
hands. Upon this point we would, if possible, fasts n
the mind of every member of the profession. The fol-
lowing is the clause of the bill which is intended to be
brought to bear against cholera, and the capability of its
practical aj plicatien will probably depend upon the rapidity
of its advance. At present this is such as to render it im-
perative that no time should be lost. The pestilence now
threaten s the Continent in one immense column, extending
from Norway to the Nile. Radiating in its uterine, from
Asia, it ban now involved both the continents of Europe and
Africa in its route. We have no doubt this hovering pl.t.•.
has shortened many a parliamentary discussion, and recon-
ciled many an uneasy member to distasteful elation in Lord
Morpeth's measure. Wh. n the s. mien has ended the wo. k
of others, we fear the labour of Lord Morpeth will but have
begun. We shall be happy to prove our vaticinations incor-
rect, but our forebndings are gloomy; and we only trust that
' dearth may not add the miseries of general want to the train
f pestilence : ' And be it t nacted that, from time to time
after the passing of this act, upon the petition of not lets than
one-teeth of the inhabitants rated to the relief of the poor of
any city, town, borough, parish, or place, having a known or
defined boundary, not being less than thirty in the whole, or
w here it shall app• ar that the pro rtion of deaths in any city,
town, borough, parish, or place, from typhus fever, diarrhce I,
searlatina, or other febrile epidemic, endemic, and contagions
diseases claimed in the registrar-gt neral's returns as eymotic,
have, on the ge of three years previously to obtaining
such return, exceeded the proportion of 20 per cent. of the
total deaths, of have exceeded the average rate of deaths
front such cause s, either in the repistretion districts which
include other towns or places in the same county, or the
general average rates of such deaths in the registration dis-
trict., including other towns in the whole kingdom, a• shown
by any returns mad' or to be mad by the registrar-general,
the 0.-neral Bourd t f Health may, it and when they shall
think fit, direct a superintending inspector to visit such city,
town, borough, parish, or place, and to make public inquiry,
and to examine witnesses, as to the sewerage. drainage, and
supply of wan r, the state of the burial-grounds. the number
and sanitary condition of the inhabitants, and as to any local
acts of parliament in force within such city, town, borough,
parish, or place, for paving lighting, clealaing, watching,
regulating, supplying with water, or improving the Fame,
or having relation to the purpo-es of this act; also as to the
natural drainage areas. and the existing municipal, parochial,
or oth. r local bcundaries, and toe boundaries which may be
most advantageously adopted for the purposes of this act,
and as to any other matters in respect whereof the said board
may desire to be informed, fur the purpose of enabling them
to judge of the propriety of reporting to her Majesty, or
making a previsional order, as hereinafter mentioned.'
ALLEGED MURDER BY IRISH LABOUREhS.—A few
nights since, a party of Eneish atd Irish labourers were
drinking in front at the bar of the Plouseh public-house, St.
Altrins, Whilst so doing, a man named Fi. Id, who was in the
house, attempted to pus through the passage, hut was ur.able
to do so. He then made use of some insulting language
towards the Irishmen, and nesting accused them of stopping
up the passage, left the house. About ten minutes
afterwards the Irish went into one of the rooms of the
public house, g..ve a wild scream, and took up the tenets,
shovel, sad poker, with which they attacked the English
labourers, knocking down every man who came
near them. The demeese.l, a quiet, inoffensive .
man, named Edward Swaine, who was sitting over
his mug of beer, was struck over the bead with
the tongs, until the blood gushed forth; his teeth were
knocked out, his eyes were blackened, and his face fearfully
disfigured. His son was also dreadfully maltreated. The
Irishmen, atter this outrage. started off. The deceased
was removed to his home, where he died. Mrs.
Day, the wife of the farmer who had employed the
Irishmen, stated that on the night the deceased
was injured the Irishmen came and knocked her up,
and asked for the money owing them for reaping, alleging
as an excuse for coming at such an unseasonable hour, that
they were afraid to come to work again, fee they had been
threatened by the English. Having received their money,
they. went away, and bad not since been heard of.
An Inquest was held, and the coroner said, that if the in-
quiry was adjourned fir a few days, the police might be
able during the interval to apprehend the men. The inquiry
was there ore adjourned till Wt-dneaday next. The deceased
was forty-five years of age, and has left seven children to
=lure his loss.