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was given to one of them by a lady's-maid, who said it was brought from Paris.

Mr. Girdlestone and Mr. Metcalf moved for the injunction; and Mr. Richards and Mr. Wood opposed.

His Honour said, he felt some difficulty about granting the injunction, because he could not but think there was a substantial difference between the thing that was claimed by the plaintiff's specification, and what the defendants had been making. It was not for him now to pronounce an opinion whether the patent was good or not, but he thought there was a sufficient difference between the articles manufactured by plaintiff and defendants to justify the Court in refusing the injunction, and directing the plaintiff to bring such action as he should be advised, to establish the validity of his patent, with liberty to either party to apply to the Court. [We pointed out the untenable character of this patent at the time it was specified. See Mech. Mag. vol. xxxiii. p. 445. ED. M. M.]

IRON SHIPS.

The most venerable, the most deeprooted, and by far the most respectable of all our national prejudices, is that which every person of English birth entertains in favour of the " Wooden Walls of Old England." Identified as they are with our noblest triumphs as a peoplewith centuries of inviolability at home and of conquest abroad-it is not to be wondered at that we should love them dearly. The "good old times" have handed down to us nothing that we_venerate more, if indeed so much. Even our rights and liberties-yea, the very monarchy itself-may be said to have always held but a secondary place in our regard. We have put up with tyrants and done without kings, but never has the idea once entered into the national mind of dispensing with our "wooden walls." Of no common wood, too, are these same walls"hearts of oak" every one, and of sound old English oak the best of them. Loved they are, not only for what they have done for us and for our forefathers, but for their own sakes, as (mostly) natives of the same sea-girt soil, and partakers of the same illustrious fortunes. England's glory and safety, and England's wooden walls are so intimately mixed up together in our memories and affections, that to separate in our thoughts the one from the other is found next to impossible.

The day is at last come, however, when John Bull must be reasoned out of this

ancient prejudice-when he must be taught to place his trust in walls of other stuff than wood-when, if he would have his "meteor flag" brave for another "thousand years" the "battle and the breeze," he must build his floating towers of a more impregnable material, than any which his native forests have ever produced.

It may perhaps serve to procure from the old gentleman a more patient hearing for the subject matter of our present discourse, if we state at once that there is nothing outlandish-nothing French, especially-in the material proposed for his adoption, and that it has as good a claim by right of birth to his favour, as his ancient oaks themselves. All that is required of him is to build his ships of iron instead of wood-of iron, the produce of our own mines, and the industry of our own people-made from native ores, with the aid of another of our native products, coal-and both the iron and the coal being things which we possess in greater abundance and can produce cheaper than any other nation on the face of the earth.

The use of iron for ships is commonly supposed to be of very recent origin, but Mr. Grantham, the author of a work on the subject which has been just published, and is by far the best on it which has yet appeared, shows that its value as a material for ship-building has been known for a great many years, during which it has been making sure though slow progress towards its now fast-extending popularity. Forty years ago boats of iron were known upon canals; and some of this description were lately cut up, which had been twentyeight years in use. The first iron vessel

that ever put to sea was the steamer Aaron Manby, built by the Horsley Iron Company, for the Seine, and named after its spirited projector. She was completed in 1821, sent to London in parts, put together in one of the docks, and navigated by no less a person than Captain (now Sir Charles) Napier, from London to Havre, and thence to Paris, being, says Mr. Grantham, "the first and only vessel of any description that ever went direct from London to Paris."(?) Mr. Manby built subsequently three other iron steam-vessels for the Seine-one at

"Iron as a Material for Ship-building, being a Communication to the Polytechnic Society of Liv erpool-By John Grantham, C. E., President," 96 pp., 8vo, with numerous plates. Simpkin and Co., and Weale, London.

the Horsley Iron Works, and the two others at his own works at Charenton, in France. The whole of these vessels are understood to be still at work on the Seine. Mr. Manby states, as of his own knowledge, that "from 1800 to 1822, the hull of the Aaron Manby never required any repairs, although she had been repeatedly aground with her cargo on board." The next iron steam-vessel mentioned in Mr. Grantham's retrospect, was built, under his father's superintendance, by the Horsley Company for the Shannon navigation in 1824-5; 66 Since then she has been constantly at work, and is now in good condition,"

"This vessel was the origin of the extensive and spirited company which now occupies that splendid river, and which is conferring important benefits on the large tract of country through which the Shannon flows. My friend Mr. Williams, managing director of this and the City of Dublin Steam Packet Company, at this time directed his attention to the subject of iron vessels. With his usual discernment he foresaw the advantages to be derived from this source to steam navigation, and has ever since been a steady advocate of the principle. It was at his recommendation that the Shannon Company continued to construct iron steam-vessels, and there are now six at work, all in excellent condition, two of them in salt water." -p. 8.

Mr. Grantham's notices of the subsequent progress of iron ship building do not follow in very regular order, and are, on the whole, extremely incomplete, but, such as they are, we give them as they present themselves.

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Iron vessels now began to attract the attention of those who were engaged in river and canal navigation, and several were built in this country and on the Continent. "The first that were built in Liverpool were undertaken by Messrs. Fawcett and Co.. and under the superintendance of Mr. Page." Shortly after this time Mr. John Laird, of North Birkenhead, commenced building them on a large scale, and has since been extensively and successfully engaged in this pursuit. Mr. Fairbairn, of Manchester, also very early took an interest in iron vessels, and was a party to a series of experiments made at Glasgow, in which iron vessels were employe i." Many others have now commenced the business, and numerous iron steamers, and iron sailing vessels of large tonnage are now afloat or building.

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Great numbers of iron steamers are now plying on the Thames (where the principal builders are Messrs. W. Fairbairn and Co., and Messrs. Ditchburn and Mare,) the Mersey and the Clyde, and on nearly all the continental rivers. Some of a larger and stronger description are regularly employed in making sea voyages with heavy cargoes." "The iron steamers running between Liverpool and Glasgow, and built by Messrs. Tod and Macgregor are well known. Of these the Princess Royal is the largest, being upwards of 800 tons. She is a fine vessel of immense power, and is unequalled in speed as a sea-going steamer.' "Iron vessels also are now fighting our battles in the East, among which, the Nemesis and Phlegethon, built by Mr. Laird, are entitled to particular notice from the prominent part these vessels have taken in the Chinese war." "Of iron-sailing vessels, some have made voyages, both to the East and West Indies." "The Ironside was the first iron-sailing vessel of any magnitude that was employed for sea voyages, and she has been highly successful." The Great Britain, now building at Bristol, and better known as the Mammoth-the completion of which the scientific world is truly stated to be awaiting with intense interest,-is to be all of iron. To these historical particulars we must not forget to add, that Mr. Grantham himself engaged about three years ago very extensively in the building of iron vessels in partnership with some other gentlemen, (under the firm of Messrs. John Grantham and Co., of Liverpool,) and is therefore well qualified by special acquaintance with the subject, as well as by general scientific attainments, to write upon it with advantage to the public.

The advantages which iron vessels possess over those of wood, are treated of by Mr. Grantham, under the heads ofStrength and Lightness. Capacity for Stowage. Safety. Speed. Durability. Economy in Repairs. Cost.

Draught of Water.

And in every one of these respects, he proves clearly and satisfactorily, that iron vessels have decidedly the advantage. We select for exemplification, one or two striking passages.

POSSIBLE MAGNITUDE OF IRON VESSELS.

"The great strength of malleable iron to resist strains in every direction is well known; but, to those who are not conversant with the subject, the extent to which this advantage may be carried is not at first apparent; or how the material may, from comparatively small pieces, be so combined in large masses, as to form the ponderous body of a ship; and they are thus too apt to prescribe a limit to its use. An opinion, indeed, is now very generally entertained that iron may be suitable for small craft, but is inadequate for the construction of vessels of heavy burthen. This, however, is a supposition so erroneous that the reverse would be much more correct; for large vessels will afford the best practical demonstration of the superiority of iron for ship-building. In the application of timber, obstructions increase in a ratio proportioned to the increased size of the yessel to be built. How often has the shipbuilder the greatest difficulty in obtaining timber to suit the varied curves of our finest ships! How often is the country despoiled of its noblest ornaments by the tempting prices he is compelled to offer for its most magnificent oaks, the largest of which are frequently insufficient for his purpose! How are his brains racked, and his patience tried, in seeking for crooked timber necessary to frame a sharp floor, or a square bilge! How often is he obliged, though he knows it to be injurious, to scarf the frames, for which no timber can be found sufficiently large to enable him to avoid such defects! And is not this one cause, amongst others, why our building yards are empty while our ports are filled with ships from other nations, in which timber is more plentiful and the choice more extensive!

"But how stands the case when we turn to iron? Where is the frame, even of the most intricate form, that our smiths cannot mould? Where the frame or beam so large that iron cannot be found of which to fashion it, and that, too, if need be, without a scarf? Here there are no knots, no sap, no cutting across the grain. Here there is no useless timber, placed merely to fill in, or to cross buts. Here every inch of material is of service, and every scrap applied to some useful end."

"If we view the subject with respect to very large vessels-ships of the line or firstclass steamers, in which intermediate decks are not only not objectionable, but requisite for the guns and stores, and in which entire or partial bulkheads may be multiplied without causing much inconvenience-we have in iron the means of dividing the shell into

small sections, affording the strongest supports directly opposed to the strains that tend to disturb the form of the plates, and in the direction in which they can least resist such strains. The sides between these decks and bulkheads would be strengthened by the ordinary mode of framing. In addition to this, the lower part of the vessel might be again intersected by longitudinal divisions; and these decks, bulkheads, and subdivisions would not only be securely fastened to the shell, but to each other, the whole thus becoming a mass of almost irresistible strength, meeting the strains in whatever direction they might arise, while, at the same time the weight would be far below that of a timber vessel of only moderate scantling, and the room for stowage would be much greater."

DURABILITY.

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"Where, I would ask, in the catalogue of objections, real or fancied, to iron ships, is there one to be found equal to that dreadful scourge to wooden vessels-the dry rot; the effects of which are too well understood by shipowners to require any lengthened remarks from me? No age has been without its nostrums, its quackeries, and its infallible remedies' for the dry rot, and no period has been so productive of them as that in which we live; but, from all I can perceive, this plague is as prevalent as ever. A circumstance which has recently fallen within my observation is strongly illustrative of this subject, as involving the comparative merits of wood and iron. On removing the timber-work of the John Garrow, preparatory to the alterations determined upon in that ship, we find that the dry rot had already (though she was not three years old) begun its work of destruction. That part of the lower deck which had been laid some time after she was launched had become decayed, and all the timber not exposed to the air was more or less affected. The iron, on the contrary, though it had been exposed to a fourteen-months' voyage, without being either cleaned or painted, was in a most satisfactory state. Not only were the plates and frames free from any perceptible injury, but the edges of a number of square boltheads, in and about the rudder, still retained their sharpness, and appeared to be perfectly free from corrosion. The dry rot in wooden ships (which finds no parallel evil in those of iron) is frequently as remarkable in the earliness of its commencement as it is invariably rapid in its progress, and no appliance hitherto resorted to has, in all instances, been effectual to avert its insidious development, or to arrest its destructive progress. How many stately vessels are now mouldering away under this destructive visitation, while

their fine and graceful forms conceal the treacherous enemy within !"

ECONOMY IN REPAIRS.

"The wear and tear of iron vessels (and I speak confidently from actual experience) are practically trifling, and the repairs are consequently light. This item, which in wooden vessels presses so heavily on the profits, is, in iron vessels, of but slight importance; and although the comparison will be found very favourable in iron sailing ships, the fact will be more clearly shown by reference to steamers. The usual calculation for a timber-built steamer is, that the expense of repairs will, in ten or twelve years, have equalled the first cost. In a well-built iron steamer repairs will not, I believe, have become necessary within that period, provided the vessel has not been injured by accidents; and, under any circumstances, I feel confident that it will be more expensive to keep in repair the copper sheathing alone of a wooden vessel, than to effect the whole repairs in the hull of an iron vessel.

"I revert to canal boats as furnishing a fair demonstration of the comparative merits of wood and iron. My informant in this point states that iron vessels are kept in repair at very little expense, but that wooden boats, when four or five years old, begin to be very expensive; as much so, indeed, in one year, as iron boats will in three or four, or even more. He mentions boats which he knows to be ten or fifteen years old respectively, and which are still in excellent condition. I know of some,' he says, 'that have been at work upwards of eleven years, and have not cost more than 21. each during all that period.' Messrs. Tod and M'Gregor, of Glasgow, in writing on this subject, say, Some of the vessels we built were not in dock, or on a slip for four years: their bottoms were never seen, yet when examined they were found to be as entire as on the day they were launched. The hulls of some of our iron river steamers have not cost 11. each these five years. Knowing their stability, we are very anxious to get sea-going vessels of iron introduced. The Royal Sovereign was, we believe, the first regular sea-going iron vessel in this country. The first six months she ran 25,000 miles under great disadvantages, she having to encounter dark nights and low water in coming up the Clyde; yet during this time lost not one trip, but was punctual to the time advertised.'

"In the event of accidents, the repairs of iron ships are extremely light, and in this respect also they bear a most favourable comparison with wooden vessels. The cases that have fallen within my own observation are so numerous, and so decisive of this fact,

that, were it not superfluous, many pages might be filled in recording them.

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"The Nemesis, war-steamer, ran on one of the Scilly rocks in the British Channel with such violence that, to use the expression of my friend Mr. Claxton, the harbour master of Bristol, if she had been of wood she would most probably have left her bones there.' The damage she sustained by the shock was, however, so trifling, that she was navigated round to Plymouth, where the repairs were easily effected for about 30%."

Nor is it solely on the ground of the intrinsic superiority of iron over wood, that the case in favour of iron vessels rests. The universal adoption of the new material is recommended by other considerations, which, if iron were only as good as wood, ought to command, for them, the preference. Mr. Grantham calculates that it requires the constant occupation of about 400,000 acres of land, on which to grow the timber for the ships annually built in this country and in our colonies; and he proceeds to show, how, by the adoption of iron, not only would all that vast quantity of land be set free for the production of human food, but a new and most extensive source of profitable employment for our people be opened up.

"So much of the timber thus employed as is grown in this country occupies a proportionate amount of land that would otherwise be appropriated to agricultural purposes; so much of it as is not grown here, takes our capital, to a certain extent, out of the country; but, worse than all, our people are deprived of profitable and extensive employment by the inducement to build ships in those countries where the material is most abundant. By the evidence of Mr. Meek, who was lately commissioned by government to enquire into the state of trade on the continent, in relation to this country, we learn that it is impossible for our ships to compete in freight with those built by several other nations, owing principally to the comparatively low rate at which they can procure the materials for building. Notwithstanding the great sacrifice now being made in the revenue of this country, by the reduction of duty on foreign timber, and the consequent decrease that will probably be made in the price, the foreigner will still have an advantage over us in having the material not only considerably cheaper, but at his own door, while our supply will necessarily be precarious.

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which our ships are henceforth to be built, and the whole question assumes a widely different and highly cheering aspect. Without being in any degree dependant on foreign countries, we should find an inexhaustible supply of more suitable and less perishable material for the whole of our national and mercantile marine in our own country; from this source our iron-masters would have a fresh and a steady demand for their iron; and an increased demand for labour, both at the mines and in our building yards, would be the immediate and invaluable result."

Mr. Grantham investigates also the principal causes which obstruct the progress of iron ship-building, and finds the national prejudice, of which we have before spoken, and some other prejudices of a more vulgar cast, to be at the bottom of most of them. The supposed difficulty of steering iron vessels by the compass, he considers to be a fair ground of objection; but this also is most satisfactorily disposed of.

HOW TO REGULATE THE COMPASSES OF
IRON SHIPS.

"When the Ironside was ready for sea, Professor Airy came to Liverpool and made a series of observations upon her, with a view to the correction of the local attraction of the ship. This object he effected in the most satisfactory manner; and not the less so that the plan he adopted was exceedingly simple. Mr. Airy afterwards, with great liberality, published in the United Service Journal a list of rules, by observing which, any one might correct the compasses of iron vessels, without difficulty.* This system is found to be so efficient, that when applied to iron vessels the compasses are generally more correct than those in vessels built of timber. Few ships are free from some local disturbing influence; but it is not considered to be so great in wooden ships as to require correc

The operation may be shortly described as follows:-Having fully completed the equipments of the ship, especially as regards the iron-work, and having determined the exact position in which the compass is to be placed-take a point on the deck exactly under it-through this point describe two lines on the deck, one parallel to the keel and the other at right angles with it. Provide two powerful magnets, about 2 feet long, and a small box, 7 inches long by 3 wide, full of small iron chain, or small pieces of iron, laid in different directions. The vessel, being in a wet dock, should be firmly moored by four hawsers, and her head being made to point exactly to the magnetic north, as ascertained by a delicate azimuth compass on shore, an observation should be made. The needle will now probably be found to be very incorrect: one of the magnets should then be slipped along the athwart ship line, either over or under the deck, till the needle points correctly. The ship's head may then be turned due

tion, and the commander having discovered its extent, makes allowances for it in his calculations. The compasses in iron ships are, however, so accurate, after being corrected, as to be free from any sensible error.

"The power of the magnets, and the intensity of the magnetism of the ship, will probably alter by time; but I have not heard that this effect has yet been observed on any compasses that were well corrected. A careful navigator would, however, soon observe any deviation that might arise in them, and on his return to port have them again corrected; as iron vessels become more general, some one will be found in each port capable of performing this operation with sufficient exactness for all practical purposes."

The Construction of Iron Vessels is treated of in great detail under the diferent heads of-Keels-Stem and Stern Posts-Floorings-Side Frames-Gunnels - Plating Jointing-Single and Double Rivetting · Deck Beams and Bulkheads and on all these matters, much valuable practical information is communicated.

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east, and the other magnet, being placed on the fore and aft line, is so regulated that the error, if any, in the needle, is corrected in this position also. The vessel should then be moved round to all the four points, north, south, east, and west, and any error now observed may be corrected by again changing the position of the magnets It is now necessary to point the head of the ship towards the north-west, or south-east, and any deviation that is observed will be corrected by the use of the small box of chain, the exact spot for which must be determined by trial. These corrections carefully attended to will cause the compass to be free from all sensible error. The magnets should be of the best description, and be placed in a box full of tallow, which box may be nailed to the deck or the ceiling of the cabin.

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