Abbildungen der Seite
PDF
EPUB

VOL. XXXVI.

WIGNEY'S PROPOSED BRIGHTON HARBOUR.

Mechanics' Magazine,

MUSEUM, REGISTER, JOURNAL, AND GAZETTE.

[merged small][merged small][merged small][graphic]

what fe at a imagh vertiget, and seth for egun, entry and frish, be bwas valides yr y para a gher ka Lampen estimation. It's an achievenest of mind and morals. Sether at

and delicate benderat — Corregendcat of the

Tester Imescitare-The Industrial Sosery of Muhausen have addressed to the French

mister of Commente, a memoir in the importance of stagting an mit if messure for the force of m chines, cinsidered ant aniy in the power exerted, but in the time magarred. The Society observe, that The antal extimation of horse-power is not uniform, and propose that the unit for France should be the firme my stored to raise one Bogramme to the height f a metre in a second. To this unit they propose that the name of dyne, from the Greek root, signifying, “moving force," should be applied, and then that it should be compounded with Greek and Latin words, in the same way as the metre, the gramme, b. Thus the kilodyne would signify a thousand tames this unit, and the millidyne would signify the thousandth part of the same unit.

Cure for Damp Rooms-A correspondent of the Bengal Hurkaru asks, "How the floors of lowerroomed houses may be cured of humidity?" By a barrel or two of tar laid on and covered with fine sand, and then beaten as floors are wont to be. The remedy is cheap and infallible. A suite of rooms, to our knowledge, which were so damp that the mats rotted in a month, were thus laid with tar, and there has not been the slightest symptom of dampness for the last six years. A set of mats now lasts two and three years, and the white ants have disappeared.

Naval Architecture.-We have seen a model of a vessel, of a curious and novel construction, to which we would direct the attention of nautical readers. The object is-swift sailing with facility of manoeuvring, in order to accomplish which, the keel is made very deep at a point in the centre, and slopes upwards towards the bow and stern in the form of an obtuse angle The inventor supposes that a vessel with a keel so constructed, would sail very close to the wind, while it would obey the helm much more quickly than an ordinary vessel, as it would turn in the water as it were upon a pivot. There is also a peculiarity in the rigging, the masts, three in number, radiating from the centre, the mainmast being upright-the foremast sloping forward, and the mizen having a similar rake backward. This arrangement is to suit the form of the sails, which are, with the exception of some of those on the mainmast, triangular, with a view to have the principal pressure on the canvass as low as possible for the sake of safety, and also to facilitate tacking. It is impossible to explain the plan thoroughly without diagrams, and we question whether even nautical men could venture a decided opinion on its merits without an experiment en a Meanwhile we think the invention large scale. worthy the attention of the Northern Yacht Club, or some gentlemen interested in naval architecture. The constructor of the model is Mr. Dempster, Kinghorne-Sodel Paper

Cipper Sheathing-A paper, by Mr. Wilkinson, was read at the Institution of Civil Engineers Fe

22. A member remarked, that his attention had deen drawn to protection afforded te timber de coal tar when properly prepared and speed the expe riment had been tried careful or deard an India chy-some partons dech on with recale tie and others 2 cat sar: the larger dai preserved the timber Avm the worm faring a ung verage, while in many places the Kemer dat fotod.

He attributed the superior qualities of the coal tar
to its containing a quantity of sulpho-cyanic or sul-
pho-prussic acid, which inevitably destroyed animal
or vegetable life. A member had observed, at New
York, that piles prepared by kyanizing had been
destroyed in the same situations, where timber,
which had been saturated with coal oil, had resisted
the attacks of the Teredo. The statement of the

last speaker was confirmed by a member, who stated,
that in the Mediterranean, where the ravages of the
worm were most extensive, the vessels being rarely
coppered, were entirely protected by prepared coal
tar. The coal tar must, however, be deprived of
the ammonia, as that substance produced imme-
diate decay in timber: ammonia might be advan
tageously used for manure in peaty soil, as it de-
stroyed the vegetable fibre with great rapidity, and
produced rich soil.

Earthquake in Cornwall.-A severe shock of
earthquake was experienced on Thursday morning,
the 17th ult. at about half-past eight, throughout
the great mining districts of Cornwall, extend
ing from the sea shore to the south of Helstone
almost the opposite coast, north of Redruth.
shock was distinctly felt at Flushing, Falmouth
Penryn, Gwennap and Redruth, but did not rea
so far eastward as Truro. The miners at work
the lower levels at Trewavas, which are under
sea, in the parish of Breage, hurried to the surf
supposing that an irruption of the sea bad tak
place into the mine, as they heard a confused ne
which accompanied the shock. This phenome
is exceedingly rare in Cornwall.

Electro-Lace.-At the London Electrical Soci
(Feb. 15,) the Secretary read a description of "
tro-lace," a novel, but pretty application of the
trotype. The basis is net, prepared according
the usual plans. A few hours' action so cove
with copper, that it seems converted into that m
Specimens were exhibited, which were much
mired. It opens a new and wide field for
extension of this art to the production of thas
licate and chaste ornaments, and fancy articles
constructed of perforated cards, &c. The
readily plated; nor is the application confin
this article alone, but may be extended to
various gauzes and delicate fabrics with whic
market abounds.

The Little Western is certainly a favourab
ample of the skill of Bristol mechanicians,
there is any thing either in the structure of
or machinery pre-eminently excellent, we
deny. In the production of the vessel there
to have been too great a straining after
and there are evidences of a disposition
arrangements, not so much by the consider
what is excellent, as of what is unusual.
lowing are some of the proportions of the ve
engines: she is 721 tons; measures betw
pendiculars, 200 ft.; over all, 216 ft.; keel.
breadth of beam, 27 ft., and, including padd
47 ft.; length of saloon, 44 ft., by 24 ft. wide
cabin, 20 ft. long.—The Civil Engineer
tect's Journal.

Intending Patentees may be
gratis with Instructions, by applicati
paid) to Messrs. J. C. Robertson
166, Fleet-street, by whom is kep
COMPLETE REGISTRY OF PATENT
(from 1617 to the present time.} /
British and Foreign
prepared or revis

USE

[ocr errors]

Mechanics' Magazine,

MUSEUM, REGISTER, JOURNAL, AND GAZETTE.

[graphic]

THE

ON THE CONSTRUCTION OF CAST-IRON AND CONCRETE BREAKWATERS FOR FORMATION OF HARBOURS, PIERS, JETTIES, WHARFS, DOCKS, EMBANKMENTS, GROYNES, ETC. BY MR. GEORGE ADOLPHUS WIGNEY, Brewer, BRIGHTON. Sir, Having conferred on me the favour to insert the principal portion (No. 963, page 70, of the present volume of your valuable work) of my Address to " My fellow Townsmen," relative to the formation of a harbour of refuge, and for pleasurable purposes, for the town of Brighton, constructed of solid breakwaters, composed of cast-iron plates filled with concrete, I now send you a perspective sketch of the same, and of the lighthouse, the two adjoining towers, and intermediate caissons, which I suggested should be first constructed and put down as an experimental test of the principle, and with a view to the obtainment of requisite experience, preparatory to the execution of the whole.

Having furnished explanatory details relative to the work as a structure, in the Address referred to, and which, with the accompanying sketches will furnish sufficient information to your readers of the materials, and the mode and principle of its construction, a few additional particulars omitted in that Address, and furnished in the same consecutive order, will alone be requisite to convey to their minds, all that appears to me to be needed on the subject.

1. The Breakwater considered as a Structure. A perspective design of the harbour, and a model of the lighthouse, the two adjacent towers and the intermediate caissons, have for the last six weeks been exhibited at the Town Hall of this place, and the only objection, which has yet met my ears to it as a structure is, the anticipated destruction of the cast-iron plates by oxidation. To obviate such apprehension, I beg to state, that the coating of them with gas tar, I propose should be accomplished in a way suggested to me by Mr. Rutter, Manager of the Original Brighton Gas Company's Works, by causing each plate, when cast, and cooled down to a suitable, yet elevated temperature, to be plunged into a tank of gas tar, when, being in an expanded state, the tar will, in a slight measure penetrate its pores, and by subsequent contraction retain it within them. Concurring with Mr. Rutter, in opinion, that by such a procedure, they will also acquire a highly glazed and concentrated coat, well calculated to resist the action of salt water, I avail myself of this opportunity to acknowledge and state his suggestion, and at the same time to express a request to any

of your numerous correspondents, not only to oblige me through the medium of your pages with any useful suggestions they may be able to furnish, but also to point out any defects which they may perceive in the principle or materials of the proposed structure. I trust that my deviation from my profession as a brewer to take up temporarily the profession gentleman of that profession to withhold any of an amateur engineer, will not induce any useful information, the more particularly as to their contributions to your pages, I stand principally indebted for that little portion of knowledge which I possess in this department of the sciences. Should the gas-tar thus applied be deemed, or found insufficient to furnish the required protection, it becomes a question of efficacy and cost, whether zinc might not be advantageously employed to protect those plates which may be constantly and occasionally immersed in water. But, independent of either resource, I presume that their durability would be very considerable, and much more so than wood, which is so subject to the ravages of sea lice, of which the piles of our chain pier already furnish a demonstrative proof.

The whole of the flanges I propose to turn inwards, with a view to protect the bolts from oxidation. The concrete may be composed of lime, sand, and gravel, and concentrated gas-tar and gravel, the latter material to be placed in contact with the plates within in the form of blocks, and the centre to be filled with the former. I feel pleasure in being able also to record for publicity, that which appears to me to be a most valuable suggestion for the improvement of the principle of construction of my breakwaters, as furnished me by Mr. Matthews, who has for about the last 20 years acted as the managing master of the chain pier, and whose judgment and experience in such subjects, I think no one will doubt. To diminish the force of the waves, Mr. M. suggests, that both towers and caissons should be perforated with a series of cast-iron tubes passing through the concrete and the sides, open at both ends, flanged at the extremities, and thereby connecting more firmly together the opposite sides; placed of course at a suitable angle from a horizontal position, dipping toward the exterior, (or as it may be termed, the storm side of each breakwater,) in order that a portion of the water composing each wave, may pass through each tube, and thereby break and divide its impulsive force. Being posited at such an angle, such portion of the water of each wave, as

WIGNEY'S BRIGHTON HARBOUR.

is not forced through to the inner basin, for want of a sufficient impelling force, would return again to meet, and in a measure break the force of each succeeding wave.

II. As a fortified Harbour and an armed line of defence for the Town in time of War. -The paramount duty of a paternal government, appears to me to be, to provide for war in the time of peace, not only with a view to prepare for inevitable defence, but also to repress any agressive disposition which may be entertained by latent enemies, by our exhibition of real defensive and offensive power, ever ready to be brought into prompt and energetic action. The measures which our executive have adopted for offensive operations, both as relates to the navy and army, recent events have proved to be adequate to present wants, and offer the satisfactory promise of capabilities equal to any future need.

195

But such cannot be said of our defensive resources; for where between Dover and Portsmouth (without travelling further) is there a single port fit for the entrance or exit of a defensive fleet? Or where is there a battery fit to repel a single ship of war? Having heard of and seen, and somewhat felt, the general consternation and dread that prevailed along the southern coast, in early life, when those formidable and extensive preparations were made on the part of France for the invasion of England-when mercenary troops were hired and encamped along our shores-when Sussex guides were appointed to lead the aged and the young, together with the weaker sex, into the interior,-when the land defences, the Martello Towers, few and far between, were erected and which invasion, with all its attendant horrors, only appeared to be pre

[graphic][subsumed][ocr errors][ocr errors][subsumed][subsumed][ocr errors][subsumed][ocr errors][subsumed][subsumed][ocr errors][subsumed][subsumed][ocr errors][ocr errors][subsumed][ocr errors][subsumed][subsumed][subsumed][ocr errors][ocr errors]

vented, by the diversion of those immense forces which were collected at Boulogne for the purpose, caused by the threatening and aggressive attitude of the great Northern Powers-I cannot but put the question to others and myself, why may not danger of an equal, or far more serious character, arise? What may be the promptings to aggression, and what the increase of power to inflict misery and devastation on our shores, it is impossible to foretell; considering especially the facilities which steam vessels of war, and improved projectile implements of warfare, in existence and in embryo, afford to powerful and ambitious neighbours to carry schemes of devastation, (if not of conquest,) into sudden execution, while cir

cumstances may have placed our floating bul

warks at too great a distance, or beyond the reach of rescue, to arrive in time to avert the impending evils that may be poured upon us at every turn and opportunity. Where are the improvements of defence which have been, or rather might have been, effected along our unsheltered coast? At the time I allude to, Brighton, though in its infancy, was crowned with three batteries,-a western, eastern, and a central; but since then, it has risen to a high state of opulence, and grandeur, and those defences are diminished from three to one, and that one, as compared with the marine frontage, and extent of the town, may fairly be termed but a state toy, merely kept up for the purpose of firing royal

0 2

« ZurückWeiter »