The Liverpool Standard and General Commercial Advertiser.
Liverpool, Merseyside, England, 1842-03-11 00:00:00

THE POLYTECHNIC SOCIETY.

The monthly meeting of this society took place last night,
at the Royal institution, and was numerously attended, the
subject announced for the evening being an address from the
President of the institution, John Grantham, Esq. " On
iron as a material for ship-building ; including a description
of the ' Great Britain,' of Bristol," &c. Amongst those pre-
sent were his worship the Mayor, Mr. Sands (chairman of
the Dock Committee), Mr. Charles Parker, Mr. Shaw (of
the Dublin Steam-packet Company), Mr. M'lver (of the
British and North American Royal Mail Steam Company),
Dr. Brandreth, l‘lr. Daniel Mason, Mr. Schuyler (the Ame-
rican Consul at this port), Mr. John Walker, Mr. Daniel
Mather, Mr. Bolton, jun., and others.
Mr. HENRY DAWSON (the President, Mr. Grantham,
having opened the business of the evening) was called to the
chair.

Mr. GRANTHAM commenced by stating that the object of
the present communication was to institute an inquiry into
the advantages to be derived from employing iron, as a ma-
terial for building ships, and to compare such vessels with
those constructed of timber. After a few introductory
remarks he said, some explanation might be expected as to
the opportunities he had had of forming an opinion on the
subject. His attention was first directed to it in consequence
of his father having, in 1824, procured a small iron vessel to
be built to navigate the Shannon. and the canals connected
with it, from which time his mind had been constantly directed
towards it, and he had had the most favourable opportunities
of examining both woc.den and iron vessels of ail descrip-
tions, having been engaged in building several of the latter,
some of which were on a large scale. He had also been
assisted by his professional experience as a mechanical en-
gineer and boiler-maker—affording him a knowledge of the
capabilities of iron, the mode of working it, and the requi-
site proportions to obtain any desired result. In proof of
his sincerity in behalf of iron for ship-building, he had de.
termined, three years ago, with other gentlemen, to engage
seriously in the business of building iron vessels, and they
had erected new premises on a suitable site. lie would not
enter upon the subject of naval architecture, or discuss the
merits of peculiar models of vessels, further than with refe-
rence to iron being more or less suitable to carry out prin-
ciples known to be favourable for peculiar desirable qualities
in steam or sailing vessels. He concluded his exordium by
expressing his thanks to several friends for the information
they had so readily afforded him, and expressed the pleasure
he should have in receiving any facts, additional to those he
had already collected, with which he might hereafter be
favoured.

It was a common error to suppose that vessels had only
recently been constructed of iron; and that iron workers were
alone advocates and promoters of the principle. The value
of iron for such a purpose had long been known, and had
for many years been making a sure, though slow, progress
towards its present improved state. Iron vessels were first
built for the canals of this country, as far back as 40 years
since, and some of these, he had reason to believe, were still
in existence. Several facts had also transpired at the meet-
ing of the British Association in Glasgow on the subject.
His partner, Mr. Page, had been engaged in building iron
canal boats upwards of thirty years ago ; and he had him-
self seen some in Staffordshire of such an age that he could
not ascertain the date of their construction. A friend of.
his in that county had also written to him, that he was then
cutting up some iron vessels that had been at work 28 years,
a strong evidence of the durability of the material.

The 'first iron vessel that put to'sea was built by the Horse-
ley Iron Company, for the Seine, and called the Aaron Man-
by, after the name of the projector. He had last month
received a letter from Mr. Manby on the subject, from which
it appeared the vessel was constructed under a patent taken
out in France, in 1820, where he and his friend Captain, now
Admiral, Sir Charles Napier formed a society. The boat was
completed in the following year, was sent to London in parts,
and there put together. She took in a heavy cargo, and
Captain Napier navigated her himself from London to Havre,
and thence to Paris, without unloading any part of the cargo,
being the first and only vessel of any description that ever
made the voyage direct to Paris. Mr. Manby afterwards
built three other iron steam-boats (two of them in France)
for the navigation of the Seine, and they continued to work
prosperously till 1830, when, owing to particular circum-
stances, they were sold to another society, but still continue
at work—the Aaron Manby (which never required repairs
from 1822 to 1830) being now employed as a tug.
The next iron vessel with which he was acquainted was
that built by the Horseley Company, under his father's su-
perintendence. She was commenced in 1822, and put to-
gether at this port. She crossed the channel iu the winter
of 1824, and proceeded to her destination—Lough Derg, on
the Shannon—since which she has been constantly at work,
and is now in good condition and daily employed. This vessel
was the origin of the extensive and spirited eompany which
now occupies that splendid river. The first iron vessels built
in this town were by Messrs. Fawcett and Co., in their boiler
yard, Oil-street, then under the superintendence of Mr.
Page. Amongst these was one called the Alburka, which
went on Lander's unfortunate expedition to Africa. Shortly
after, Mr. John Laird commenced building them on a large
scale, and had since been extensively engaged in this pursuit.
The lecturer then proceeded to describe the ordinary
method of constructing iron vessels, which he very happily
illustrated by diagrams and models. The iron employed con-
sisted of the best rolled plates and angle bars, the supply at
Liverpool being generally obtained from Shropshire or Staf-
fordshire. It was of importance that they should be tough
and not liable to crack, so that should a vessel be wrecked,
or receive a severe blow, the plates might dingo but not
break. He entered into an elaborate and highly interesting
account of the several modes adopted in building iron vessels,
from the keel upwards, and pointed out those which he
considered the best, which was listened to with marked
attention. The scope afforded for increasing the strength of
iron vessels was almost unlimited, by evident means; but
the question as to the last disposition and proportionate
strength of the plates involved so many difficult enquiries,
that experience alone could decide the question. Plates
united by a flush joint would sustain the greatest strain from
force applied to their edge; while with lapped joints the
whole of the strain arising from a weight applied to the edge
of the plates was thrown on the rivets, excepting in so far
as such strain was counteracted by the frames at short in-
' tervals crossing them. In a vessel taking the ground or in a
heavy sea, the strain on the bottom arose from an up-
ward pressure, and on the sides two forces operated, one
given out in a vertical direction, and the other (when
afloat only) from the inward pressure of the water. From
these two forces arose the compound actions which caused
the strains and wrenching to which vessels were exposed.
When a ship laboured in a heavy sea the strains were
continually varying, and it was impossible to establish
any rule of entire counteraction, the only safe course
being to apply the strength which experience had shown
to be necessary, and of which the materials used were
susceptible. After explaining the greater resistance of plates
formed into a ship's side as one plate, to vertical pressure,
than the power to resist strains arising from inward pressure,
he stated that he was decidedly favourable to the lapped joint,
or clenches build, in preference to the flush joint. He showed
that in the lapped joint the plates were not so much weak-
ened by the rivet holes as was generally imagined, as about
two-thirds of the original strength of the plate was still loft,
where a double row of rivets was used, and more than half
where a single row is used. The double rivetting added
much to the strength of the joints, which he illustrated by
diagram. Assuming the strength of a solid plate to resist
tension to be 100—a double rivetted joint would be 70, and a
single one GO. He then instituted various comparative ad-
vantages of the lapped joint as compared with the flush joint
in other respects, and then described the building of iron
vessels generally in every part, for the information of those
not already acquainted with the subject.
He next instituted further comparisons between iron and
timber vessels, and claimed for the former the following qua-
lifications :-1. Strength combined with lightness.-2. Great
stonnage.-3. Safety.-4. Speed.-5. Durability.-6. Light-
ness of repairs.-7. Cheapness.-8. Draft of water.
He proceeded to state that iron vessels, in all these essen-
tial points, would be found to be superior to timber vessels.
Iron was as applicable to large as to small vessels, while, in
the application of timber, the difficulty of obtaining suitable
materials increased in proportion to the size of the vessel.
He next instituted an inquiry into the relative properties of
iron and wood, as to tension, resistance to compression, &c.
He next shewed that the hull of an iron vessel, if the shell
was originally made sufficiently thick, might be stiffened to
an unlimited degree. Additional strength might be given to
the frame at any time, an instance of which was exemplified
in the large iron ship John Garrow, now undergoing altera-
tions at the works of himself and partners. He then skewed
the peculiar adaptation of iron as a material for very large
vessels, such as ships of the line, large steamers, &c., requir-
ing intermediate decks and bulkheads, which, by dividing the
shell into small sections, would give powerful support to the
whole. _ _ _

He next stated that a comparison of the fastenings was
equally in favour of iron, and after enlarging on the other
points for which he claimed a superiority for iron over wood
(enumerated above), concluded by saying that an iron ship,
when condemned and broken up, was more valuable than a
wooden ship under the same circumstances.
Mr. GRANTHAM, who had repeatedly stated his inability
to do justice to the several branches of his subject within the
time usually allotted for the sitting of the meeting, and who
also announced his intention of publishing the whole of the
facts he had collected, as well as such observations as he had
proposed to make, and which he had necessarily omitted,—
was listened to with marked attention throughout, and sat
down amidst applause, the research and personal experience
in the construction of iron vessels having made a marked
impression on the audience.
Mr. SHAW, marine manager to the City of Dublin Steam-
packet Company, said that the body which he had the honour
of representing, had both iron and wood vessels in their
service, and on that account he had listened to Mr. Gran-
tham's lecture with a very great degree of interest
and satisfaction. For the sake of eliciting discussioo
he would read a letter from Mr. Dalzell. the survevot
for Lloyd's, upon the Clyde, who had been sent once
to report on the Iron Duke, which had been wrecked upon
the Irish coast. Mr. Shaw then narrated the substance of Mr.
Dalzell's report, which comprised objections to the iron vessel
one of which was that the compass would not act, but, on the
other hand, he bore testimony to the amazing strength of the
vessel, and expressed a confident expectation that when the
objections which be urged were overcome (of which he bad
no doubt) the use of iron vessels would become general.
Mr. GRANTHAM, in reply, pointed out the defects in the
construction of the Iron Duke. The captain had from time
to time removed the magnets, and the consequence was that
the compass would not act.
Mr. SHAW then suggested a variety of other questions,
such as the adoption of iron steamers for war purposes.
Mr. GRANTHAM said that he had no doubt that iron ves-
sels of war would speedily attain a superiority over wooden
vessels.
Mr. Cn Armus WYE WILLIAMS, after a few well deserved
compliments upon the interest with which the talented
lecturer had investigated the subject, moved a vote of thanks
to Mr. Grantham.
Mr. SAMUEL HoLmc seconded the motion.
The MAYon, and the CHAIRMAN of the Dock Committee
each described the gratification with which they had heard
the lecture, and cordially thanked Mr. Grantham for the in-
formation he had communicated.
Mr. GRANTHAM briefly returned thanks, and the proceed-
ings terminated.

THE FtINDS.—WEDNESDAY EvENING.—The deplorable
news from India received more in detail by the overland mail
as published in the Herald to-day, could not fail to act upon
the Funds, and accordingly Consols again declined, although,
considering the cause, but in a slight degree. The closing
prices were 89 to for money, and 891- to for account. Ex-
chequer Bills were also lower, the last prices being 30s to 32s
premium. The Foreign Market was altogether neglected,
and the quotations on the decline. Dutch Two-and-a-Half
per Cents were 51i to 21, the Five per Cents 1021 to 3. Bel-
gian 103 to 4. Spanish Active with the Coupons 24a to
Portuguese Five per Cents 33i to 4, the Three per Cents 191
to 201. Brazilian 66 to 7. Mexican 37a to Colombian
24 to -a.

SWIFTNESS IN TRAVEL.—As a proof of the wonders now
accomplished by steam and railroads, .r.-e may observe, that
through our noble packets running between Glasgow and
Liverpool, and Halifax and Boston, and the completion of
the railway from the latter to the upper provinces (to within
some twenty miles of the spot), it is quite possible to pro-
ceed from London to the Falls of Niagara in a fortnight !
" DID YOU EVERS ?"—Did you ever known young woman
who was too weak to stand up during prayer time at church,
who could not dance all night without being tired at all ?
Did you ever know a man with a shocking bad hat, a long
beard, and a ragged coat, who could find a respectable hotel
that was not full.
• • -

" What is man's chief end 1" asked a clergyman of a lad
" 11/s head," was the ready reply,