1818.] M. Dupin on the Public Establishments of Great Britain. 407 ཐཱ an immense length. Nevertheless, this is only a portion of the merchant ships of the capital. All those which belong to the EAST INDIA TRADE have their Docks and private Basons, one for import and another for export-goods. All the ships which carry on the WEST INDIA TRADE have their's also; and the ships of all nations are indiscriminately received in the LONDON DOCKS, while the GREENLAND DOCK, formerly ap propriated to the vessels concerned in the whale fishery, being enlarged by the labours of late years, is now devoted to a more extensive object. It is not more than twenty years since this last mentioned Dock, now the smallest of all, was the only one in that quarter. The war breaking out, and the Continent of Europe becoming impoverished, the commerce of England seemed to withdraw before our victorious flags, and we thought that Great Britain was exhausted, and on the point of ruin. But while our eyes were beclouded by the incense from the altars of our glory, an unlooked for opulence overflowed the British Empire; her rivers were no longer large enough to hold all the ships, and a lesser number of years sufficed for private individuals to construct, at their own expense, the Docks which receive the merchant fleets of the two hemispheres, than was required for a triumphant Government to build a few of the quays on the Seine. Such are the prodigies of the ocean! This great lesson will perhaps enable us at a future time to understand the real sources of power and national prosperity. But I must here confine myself to speaking of the chef-d'œuvres of art, and not of their results. The formation and building of the Wet Docks and Basons of England differ essentially from labours of the same kind which have been executed in France. Instead of being, like ours, bounded by quays, formed of smooth walls, inclined or vertical, with stones placed in horizontal layers, these walls are concave at the exterior, or the side next the water; and the layers of stone are joined perpendicularly at the surface. The piles are also inclined, and planted perpendicularly to the inferior face of the lowest stratum. The entry to the sluices is built upon a similar and equally advantageous plan. In short, the flood-gates, instead of being formed by two masses, plain and abutting at the ends, are formed by two vertical cylinders, the convexity of which makes an arch or vault, for re sisting the pressure of the water. The advantage of these curvilinear over our rectilinear forms, with respect to economy and solidity, can be geometrically demonstrated. Hydraulic works in England are distinguished by the constant use of the steam-engine for exhaustion, and for all those manoeuvres which require great and continual efforts on one spot. The removal of earth, the conveyance of stones, sand, lime, &c. are all performed by little four-wheeled carriages, drawn by one horse, and moving on an iron rail-way. These roads are composed of materials that are laid down and removed with the greatest facility, and the advantage they afford is immense. Indeed England is indebted to them for a part of her riches; for without them coals, minerals, and primary substances. of all kinds, could never have been conveyed to great distances at hardly any expense. The excavations under water, when the bottom is muddy or sandy, are made by a chaplet or line of buckets, fixed on the sides of barges, and kept in circular motion by a steam-engine. I shall specify as a model of this mode of clearing, the machine employed at the West India Docks. A barge bearing the steam-engine which moves the buckets, is conveyed to any part of the Docks, the bottom of which it is necessary to clear or cleanse. Another vessel of the barge kind, which is to receive and carry away the excavated mud or sand, is fixed alongside the former, and receives the contents of the buckets as they empty themselves by their rotatory motion. When a barge is loaded it moves off, and another takes its place; it is then laid under another line of buckets, moved by another engine, stationed at the edge of the Dock. The contents are thus raised and emptied into vehicles which go round the wall of the building, and spread them like a torrent, in a large vacant spot. This system of clearing is not only extremely simple, but vastly economical. By means of the apparatus here described, the English have not only dug out and cleared large basons, but have rendered streams navigable which were not so before, and have also removed sand-banks which obstructed certain parts of the course of their most important rivers. Another machine not less remarkable, and which is employed in all grand hydraulic works, is the Diving-bell. The 408 M. Dupin on the Public Establishments of Great Britain. [Dec. 1, form of the kind now in general use, is that of a truncated square pyramid, the great base of which is open and turned towards the bottom. Within this pyramidal trunk, two men, who descend sitting on two benches, can rise and work at their ease. Ten lenticular glasses fixed in the upper base of the bell, combine to refract as much light as gives the requisite illumination at a great depth under water. A pneumatic machine resembling a fire-engine, serves by means of a long leather tube, to convey fresh air incessantly into the bell. Sometimes this bell is suspended to a moveable axle, formed of two systems of indented bars, which, by their directions and functions, represent co-ordinate rectangular axles. By means of these axles the centre of the bell is placed over any desired point. On entering it they descend at pleasure by the aid of the axle, and the chain or rope. This apparatus is employed in building those parts of the walls of a quay which lie under water, and thus it is unnecessary to have recourse to the expensive method of erecting coffer-dams. Sometimes the bell is suspended at the poop of a vessel which conveys it where required. This machine is also employed to raise in rivers, road-steads, harbours, and docks, any ponderous articles which may have sunk, such as anchors, cannon,' the remains of wrecked ships, &c. It is likewise made use of to prepare, for being blown up, rocks which are under water, and dangerous to navigation.* Hence, if we consider the machinery now employed by the English in their great undertakings, we shall find that an immense change has been effected in the course of a few years. We know not whether it be the prejudice to which we have pointed in a preceding annotation, or real ignorance of arry such apparatus, that should lead M. Dupin to class the Diving-bell among the inventions of the last 30 years. He might have learnt from any of our Encyclopædias, and from some such works printed at Paris, that Diving-bells were employed in raising some of the treasure lost in the ships of the Spanish Armada, that were sunk near the isle of Mull in 1588; that Sinclair (ars nova et magna gravitatis et levitatis, 1669), Phipps, KessJer, Halley, Trieswald, Spalding, Smeaton, and a long list of others in succession, had in the compass, not of 30, but of 230 years, brought the apparatus from the rude state in which it first existed, to the finished, ele gant, and safe submarine vehicle which he describes. The basons and other works built in former times were enclosed by a simple system of timber-work. It was however thought, and with reason, that by devoting a small capital to these labours, the expense of keeping in repair and renewing such perishable constructions would be repaid with interest. But when maritime operations assumed an excessive activity, it was perceived that their frequent interruption, produced by repairs and rebuilding, caused a loss which might be amply repaid by a moderate expenditure. Upon this principle, bricks and cast-iron have been gradually substituted for wood in the docks of commerce; and free-stone, marble, and granite, in the ports of the state. This change is very striking along the banks of the Thames, where the oldest dock-yards still contain basons and slips constructed of wood; while the more modern establishments present nothing but quays and embankments of masonry. Along the Thames there are but very few of those modes of building formed by embedding the hull of an old vessel in the soil of the shore, with its end next the river cut open for a flood-gate. Another change not less remarkable is effected in the timber edifices built on land. Wherever there was reason to fear accidents from fire, wood has been replaced by iron. a One of the finest works of this kind is storehouse built by Mr. Rennie, along the grand West India Dock. It is eight hundred yards long, and is sustained by hollow columns of iron; the beams, the joists, the rafters and laths are likewise all of iron. Those parts which have only pressure to bear are of cast-iron those which have to resist tension are of ments of this system are so combined, wrought-iron. The longitudinal elethat its various parts can either be extended or contracted, without altering the whole length of the building. If this precaution had not been taken, it is apprehended that the least variation of temperature, would upon a length of eight hundred yards, have thrown out the extreme columns, and quickly have edifice. effected the destruction of the whole In the course of this memoir I shall have several opportunities of mentioning the new and ingenious purposes to which wrought and cast-iron are applied in England. The great docks or basons of London are surrounded by cellars, storehouses, T 1818.] M. Dupin on the Public Establishments of Great Britain. 409 and sheds of an immense extent. The quays are often covered with iron railways, and have numerous cranes likewise of iron, which are of various sizes, shapes, and mechanism. Near to the East India Docks is the largest commercial Dock-yard along the Thames. I saw one of the India company's ships launched from it, of 1300 tons burthen. This ship was a model of perfection; there were three others of a similar size, on slips in the same yard. London, considered as a focus of industry for the maritime arts, contains a number of important establishments. The Royal Society of London, the Society for the encouragement of Arts, the British Museum, and the Royal Institution, are the principal sources from which to collect materials for the theoretical part. It is about thirty years since a society was formed for the improvement of naval architecture; it made many very important experiments in Greenland Dock, on the resistance experienced by bodies moving in water. This society, abandoned by the Government, and perhaps counteracted secretly by powerful individuals, was dissolved after ten years of commendable labours. With respect to the practical part of the maritime arts, I shall mention some of the principal establishments that I visited. The manufactory of MAUDSLEY, in the Borough of Southwark, is one of the most interesting in reference to applications of iron. There may be seen in the Conservatory of the Arts and Trades at Paris, one of the small steam-engines made at this manufactory. At the same place were made the machines of M. BRUNEL, of which I shall presently have occasion to speak. There were also made at it, for the British Navy, 7000 iron cases, each capable of containing about two cubic metres of water. The introduction of these water-boxes on board ships is an incalculable advantage, both for preserving the purity of the water and the health of the crews. In another part of London, Messrs. HUDDART and BROWN have established two manufactories, one for ships' cordage, and the other for iron cables. HUDDART's ropes are spun and formed by the action of steam, on the principle of equal tension of all the threads, which gives them much greater strength than by the ordinary method of spinning. The cables of Captain BROWN are of two sorts: one being formed of flat chains, and the other of half-twisted ones, The former seem more fit for reNEW MONTHLY MAG.--No. 59. sistance in proportion to their length; but the latter appear to be more easily worked. Thus the one is preferred for holding dead weights at anchorages, and the other for being embarked on board the ships. Captain BROWN has also taken out a patent for the manufacture of iron bridges, which are extremely light, and may be furnished at a cheap rate. The greatest advantage of his plan is, that where some parts of a bridge have decayed or given way, either from age or accident, one can by means of a very simple instrument, take down and renew successively as many parts as may be necessary, without being obliged to erect large scaffold-works for the purpose. Thus a whole bridge may be rebuilt, piece by piece, at a very small expense. Those arts in which iron and hemp are used, have made great advancement towards perfection, by the emulation that exists between the inventors of new processes, and the followers of the old methods. The former to prove the superiority of the means which they attempt to introduce, have been forced to make comparative experiments in a large way, on the strength of the unwrought and the wrought materials, from which has resulted an abundance of positive information of great importance to the ultimate progress of industry. It is also near London that M. Brunel has built his manufactory for circular saws. These saws cut the smallest veneers from enormous blocks of satin wood. The operation is performed with such perfection, that the workmen have hardly any thing to do but arrange the slips as they come from the mill they have but merely to rub them to take off the roughness, and they are then perfectly plain. I shall hereafter describe the structure and operation of these saws, the largest of which is six metres, (19 2-thirds feet) in diameter. But I should exceed the limits of this analytical memoir, if I were to give only an outline of all the articles manufactured at, and sent from London, for the use both of the merchant ships and those of the state. I shall therefore proceed to take a view of London as the centre of the operations of the British Navy. From the Admiralty, situated in the centre of the principal offices of Government, messengers may reach in half an hour the arsenal at Deptford, and in an hour that of Woolwich; in four hours they can get to Chatham; in six to Sheerness, in eight to Portsmouth, and in VOL X. 3 G 410 M. Dupin on the Public Establishments of Great Britain. [Dec. 1, twenty-four to Plymouth, the most distant of all the public establishments. But notwithstanding this rapidity of communication, the telegraphic stations' can carry on a much quicker correspondence between the Admiralty and all the naval depots. These telegraphs, till lately, consisted of large square compartments in a frame, by which various signals were made. At present our Semaphore is adopted, with some alterations made by Rear-Admiral Sir HOME POPHAM, who has made great additions to the art both of land and sea signals.→ He himself explained to me the nature of his ship-telegraphs, or code of signals. The Admiralty issues general orders respecting the Navy, makes appointments, grants rewards, and orders Naval Courts-Martial. The Lords of the Admiralty go out with the ministry. The duty of the Navy-office is to direct the execution of the works ordered by the Admiralty. Provisioning the ships, arming and disarming, and in short, all that relates to the particulars of the Navy come within its province. The Commissioners of the Navy are not removed on a change of ministry. This department, at once independent and subordinate, appears to me to be a chef-d'œuvre amongst the English institutions. The Victualling Office, which since the peace, has been united to the Navy Office, has under its controul whatever relates to the procuring of food for the Navy. The principal depot of this department is at Deptford, where by the grandeur of its edifices, it seems to form a town of itself. Biscuit is baked there daily for the supply of from 24,000 to 30,000 men. Similar bakehouses are established at all the grand naval arsenals. What struck me most pointedly in these bakehouses was, the division of the labour, and the rapidity with which it is performed, as well as the means of discovering at any time negligence or fraud, whether on the part of the workmen or the overseers. The English Government would regard not merely as an act of barbarity, but of wickedness, any saving obtained at the expense of men who devote their * We never wish to lose sight of the courtesy due to a liberal and ingenious foreigner; yet we cannot yield to M. Dupin's countrymen the invention of the Semaphore. This invention is unquestionably due to a man who is too rich in valuable contrivances to be obstreporous in his claims for the honour of this-Colonel PASLEY of the Royal Engineers. strength and life to the defence of the country. Every thing with which they are furnished is therefore abundant, wholesome, agreeable to the taste, and I might almost say delicate. When I assert that a ship's crew frequently breakfasts on chocolate, I shall perhaps cause the superficial observer to laugh; but those who have profited by the lessons of Hannibal, know how much effect physical strength, added to moral influence, has in deciding the loss or gain of battles. Next to the Victualling Office at Deptford, is the Naval Dock-yard in the same town; but it is the least extensive, and the least important of any. Yet the place deserves notice, for it was here, in a private dock near the arsenal, that PETER THE GREAT came to learn the art of ship-building. Continuing along the right bank of the Thames, you arrive at Greenwich, where Charles II. endeavouring to imitate Louis XIV. in his errors and his weaknesses, built a magnificent palace, in order to withdraw the festivals of his licentious court from the gates of the capital. Soon afterwards, William and Mary, also imitating LOUIS LE GRAND, converted this palace into an asylum for invalid sailors. The celebrated Observatory, from which the English seamen compute their longitude, is built on Flamstead Hill, in Greenwich Park. It takes its name from the astronomer who first had the direction of it, and rendered it famous from the very time of its erection.* An establishment little known, but not less worthy of being so, than any of those of which we have spoken, is the Naval Asylum, a school in which are gratuitously brought up the sons of sailors and sub-officers of the Navy, who have fallen in fighting for their country. 'It is situated between the Observatory and the Hospital. The Dock-yard at Woolwich deserves * Flamstead was born at Derby in 1646. In 1674, his friend Sir Jonas Moore, then Surveyor-General of the Ordnance, and one of the greatest promoters of mathematical and nautical science which England ever possessed, obtained for him the appointment of Astronomer Royal, and in 1675 the foundation stone of Flamstead House was laid. Hence it happened that the situation of Astronomer Royal was under the supervision and pay of the Board of Ordnance; and so we believe it has continued till the last year, when an attempt, we think a successful one, was made to place it under another depart ment. 1818.] M. Dupin on the Public Establishments of Great Britain. 411 much greater attention than that of Deptford. Ships of the largest size have been built there, from the time of the famous Harry by the grace of God, built by Henry VII. to that of the Nelson, a first rate, of 120 guns. In this arsenal, I saw a machine, invented by Mr. Hookey, for bending wood. It is sufficiently strong for bending the pieces that form ship's knees; it appeared, however, to me, that too little use was made of this interesting invention. Mr. RENNIE is now building at Woolwich Dock-yard, a forge, all the implements of which are to be moved by a steam engine. They make here the largest anchors. The establishment altogether is incontestibly the first of its kind in England, and perhaps in Europe. About two or three years ago, experiments were made on a great scale, to impregnate timber with a mineral solution, which was to preserve it from rotting. For this purpose they employed a high pressure steam engine, that the gas might penetrate more easily between the fibres of wood expanded by heat. But the heat and compression were so much increased, that one day the whole apparatus blew up, by which several persons were killed or wounded, and much serious damage was done in the vicinity of the explosion. It does not appear, that any subsequent attempt has been made to repeat the experiment. At Woolwich is the principal establishment of the Ordnance Department, which includes the military engineers, and the land and sea artillery. In this last point of view, the arsenal of Woolwich became to me an object of special attention. It contains a great number of machines, well worthy of being studied; but I shall confine myself to speaking of the saws and hydraulic presses. In my work on the English artillery, I have described in detail, the hydraulic engines of Pascal, as improved by Bramah, and particularly their application to the planing of wood. A horizontal wheel is armed with thirtytwo equi-distant gouges, and has two planes at the extremities of its diameter. It is made to turn at pleasure, by a steam engine. The piece of timber intended to be planed, is made to move in a right line on a carriage, which is caused to advance uniformly by a hydraulic press, that is also set in motion by the steam engine. Thus while the timber proceeds under the wheel till it has made half its revolution, sixteen of the gouges make on it as many distinct ruts or indentions, about the breadth of a centimetre (two-fifths of an inch). Immediately afterwards the fifteen light ridges that separate the sixteen incisions or ruts, are carried off by a cut of the plane which follows the sixteen gouges. By this apparatus, in less than a minute the sides of the largest pieces of timber used in gun-carriages can be planed. A particular hydraulic press serves to elevate or lower the vertical axis of the wheel that contains the knives, so that it may be made to reach the wood whether more or less thick. Mr. BRUNEL has erected at the Woolwich arsenal, a mill of long saws, which move by the steam-engine. It is remarkable, that the whole apparatus is made of scarcely any thing but iron and copper, and also because the action and suspension of the movements are performed with great precision and simplicity. These saws act with great rapidity, and the labour they perform is immense. The Ordnance Department liberally rewarded Mr. BRUNEL for this invention; for besides the stipulated remuneration, he has received a considerable pension. After enjoying this pension for some years, Mr. BRUNEL wished to sell it, and was permitted to do so. I mention with pleasure this noble and generous manner of treating men of science. Such facts confer more credit on a government than the most refined compliments or pompous eulogia. It was at Woolwich that Dr. HUTTON made his experiments on the ballistic pendulum, which have been continued on a much larger scale by Dr. GREGORY and Colonel MILLAR, who invented a very ingenious small saw for turning. In my work on Artillery, I have given a description of the excellent apparatus used for these ballistic experiments.* We believe that besides Dr. GREGORY and Colonel MILLER, whom M. Dupin mentions, another artillery officer, Colonel GRIFFITH, took an active part in the recent ballistic experiments at Woolwich. The ballistic pendulum, we learn from good authority, weighs more than 7,000 pounds, yet oscillates with all the smoothness, freedom, and regularity of a clock pendulum, Balls of 6, 9, 12, 18, and 24 pounds weight, have been fired against the wooden block of the pendulum, with velocities varying from 800 to 1,700 feet per second, and the velocities accurately ascertained. Among the curious results of these experiments of which we have heard, we can only here mention one, viz. that when balls are fired with high |
