BLOCK-MACHINERY.

was enabled to make a calculation of the saving as to the first cost, compared with the contract prices, which would be effected by the adoption of his invention. It was as under:

These savings, if realized to the full extent, were probably not more important than the increased strength, durability, and facility of working, which have been gained by the adoption of the block-machinery.

Those parts of the machinery which Brunell had completed in London under his patent were transferred to Portsmouth, and, in the course of the year 1804, were in operation; but the increased number of machines, the improvements that suggested themselves to the ingenious inventor, the application of other machines for making dead-eyes, trucks, and all manner of block-maker's wares, besides circular and upright saws, lathes, engines for turning pins, rivetting, polishing, &c. exercised his skill and ingenuity till the year 1808, when he considered the whole system to be complete in every part, and incapable, as far as he could judge, of further improvement. From that time to the present, the block-machinery has been in full and constant employment, without requiring the least alteration, and very little repair, beyond the unavoidable wear and tear of engines that are kept in almost constant motion; and, which is still more extraordinary, without requiring the aid of the inventor, though attended only by a few common workmen or labourers; but they are superintended by Mr Burr, the master of the wood-mills, who is considered as an able and ingenious machinist. The quantity of blocks of every description, manufactured by the machinery in Portsmouth wood-mills, is more than sufficient for the consumption of the whole navy and the board of ordnance, and if pushed to the utmost extent of the works, would also have been sufficient to supply the greater part of the shipping employed in the transport service.

It may be a matter of some curiosity to know the results of this system of machinery. It is put in motion by a steam-engine of thirty-two horses' power, which, however, is applied to a great variety of other purposes at the same time, wholly independent of the block-machinery. It has been found by calculation, that four men with the machinery, as it now stands, can complete the shells of as many blocks as fifty men could do by the old method; and that six men will furnish as many sheaves as before required sixty; and that these ten men, in displacing the labour of one hundred and ten men, can with ease finish in one year from 130,000 to 140,000 blocks of different sorts and sizes, the total value of which cannot be less than L.50,000; and this is stated to be the average number which has annually been made from the year 1808 to the conclusion of the war. This number is found to be fully sufficient for supplying the wear and tear of blocks, not only in the naval, but also in the ordnance department. The consumption, however, must depend on other circumstances besides the number of ships in commission, and will be greater or less according as ships have been employed on severe or easy service, in a good or bad climate, in fine or rough weather, &c. Nor will the number here stated appear to be enormous, when it is considered what a multitude of blocks are required for a thousand sail of ships, which at one period of the war were in commission at the same time. A ship of 74 guns, for instance, requires the following blocks for her equipment:

Of all kinds in a 74 gun ship, 1430

The average number of ships of the line in commission appears to have been about 100; these would require 143,000 blocks; and allowing the remaining 900 ships and vessels to require only twice this number, there would be wanted for the first equipment of the 1000 ships of war 429,000 blocks, which, at the ordinary rate of making them at the mills, would require three years in completing.

The different sorts and sizes of blocks used in the navy exceed two hundred, and they vary from four to twenty-eight inches in length. Those above eighteen inches are more sparingly used, and the shells of the largest kinds are made in parts, and fitted together by hand.

To the completion of this ingenious machinery, Brunell gave his whole attention from the month of September 1802 to June 1808, during which time he received no other compensation beyond the daily allowance of one guinea; but as it was now in full operation, and ascertained to be capable of making a sufficient number of blocks for the whole naval and ordnance departments, it became a question in what manner the author of the invention should be rewarded. It was suggested by General Bentham, and agreed to by Brunell, that the savings of one year, as compared with the contract prices, would be a fair and not an unreasonable remuneration for the time, labour, and ingenuity bestowed on these extraordinary machines. It was no easy matter, however, to ascertain with precision what the actual savings amounted to.

Total amount received by Brunell, about L.20,000 0 0

Supposing, therefore, the whole cost of the buildings, steam-engine, machinery, interest of money, &c. to amount (which we understand to be about the mark) to L.53,000, and the net compensation for profits to about L.18,000, the whole expense of the concern was completely cleared in four years. The savings of L.18,000 on one year's manufactured articles of the value of L.50,000 amounts to something more than Brunell had originally made it by computation.

It would occupy too much space to enter into a minute description, and require more time than we can spare to prepare engravings in detail, of the various complicated systems of machinery that are employed for the completion of a block; and, after all, they would afford but little use or instruction, excepting perhaps to a professed machinist; and perspective views of the several systems would tend rather to mislead or confuse than to inform the

Block-machinery. general reader. But as everybody who happens to inspect Portsmouth dock-yard makes a point of visiting the block-machinery, we think it may be of some use, in conveying a general idea of the most striking parts of the machinery, by following the process of making a block from the rough unsided tree, till the last finish is given to it.

We have stated that the original intention of the building was that of a wood-mill, in which all manner of sawing, turning, boring, rabbeting, and the like, was to be performed, and that the block-machinery was superadded to the first design, with which, however, it has interfered so little, that, in addition to the immense number of blocks manufactured at the mill, upwards of a hundred different articles of wood-work are made by other machinery, put in motion by the same steam-engine, from the boring of a pump of forty feet in length, to the turning of a button for the knob or handle of a drawer. (See DOCK-YARD, PORTSMOUTH.) Lest, however, the engine, with such a variety of work, might be overloaded, a second engine has been added, to assist, if found necessary, or to be substituted in the event of accident happening to the other. Among the many ingenious machines belonging to the wood-mills, exclusive of those for making blocks, one of very great effect, and at the same time great simplicity, is a circular saw for cutting rabbets in the edges of deal planks, invented by Mr Burr, the superintending master of the wood-mills.

The whole of the machinery in these mills is put in motion by straps passing over drum-heads, by which the several movements, numerous as they are, are carried on without the least noise; and all the engine-work, and every part of the machinery, are so truly made, and so firmly put together, and work with such accuracy in all their motions, that though the spectator is surrounded on all sides with movements in every possible direction, and some most rapid and violent, the only noise that disturbs him arises from the cutting, boring, turning, polishing, and other instruments which are actually in contact with the work that is under execution, and none of it from the working of the machinery. All the iron work, of which it is chiefly composed, was made by Mawdsley; and there is but another workman, perhaps, in the united kingdom, who could have finished the engines in a manner so worthy of the invention.

The first wing of the building is chiefly occupied by upright and circular saws, used for a variety of purposes not immediately connected with the making of blocks. The only operation for this department is that of converting the rough timber, which is generally elm or ash, most commonly the former, into its proper scantling; that is to say, squaring it by the upright or straight-cutting saw, and then, by a circular saw, cross-cutting it into a certain number of parallelopipedons, whose lengths may bear the required proportion to the thickness of the log. Some of these pieces are again cut longitudinally, according to the thickness that may be required for the shell of the block, especially those for single and double blocks, which of course are thinner than three and four-fold blocks. This operation is performed by what is called a ripping-saw. The logs thus cut out are then taken into the second wing of the wood-mills, where the machinery peculiar for the construction of blocks is erected; and here the first process may be said to commence in making the SHELL.

This operation is performed by the Boring Machine, which, by means of a centre bit applied to the middle of the shell, bores a hole for the centre pin of the sheave, while another bores one, two, or three holes, at right angles to the direction of the first, to admit the first stroke of the chisel, and, at the same time, to serve for the head

of the mortise or mortises, according as the intended block is to contain one, two, or three sheaves. When thus bored, the log is carried from hence to the

Mortising Machine, which is an ingenious and striking piece of mechanism. The block being firmly fixed on a movable carriage, the latter is so contrived as to be made to advance to the cutting chisels, which are set fast in a movable frame. Every time the frame with the chisels ascends, the block in its carriage advances a little, so as to present to the chisels a fresh surface of wood to be acted upon at each stroke of their descent; and this up and down motion is continued with such rapidity, that the chisels make from one hundred to one hundred and thirty strokes in a minute, until the prescribed length has been mortised out; when, by raising a handle, which is done by a boy, the machine is stopped precisely when the chisels stand at their greatest elevation; and are thus left in the proper position, ready to commence a second operation. No harm, however, would happen, either to the block or the machinery, should the attending boy neglect to stop the work at the proper time, or even to fall asleep, notwithstanding the force and rapidity of the stroke; for, by a particular contrivance, the farther advance of the block is stopped, and the chisels, therefore, act in full space, and cut only the air. It is, indeed, a general characteristic of Brunell's machinery, to be so constructed as to carry with it a defence or protection against its own operations, and to counteract all ill effects that might otherwise arise from any neglect or inattention of the workmen.

The chips cut by the chisels are thrust out of the mortise by small pieces of steel attached to and projecting from the back of each chisel. They are each of them, besides, armed with two cutters placed at right angles to the edge, called scribers, which mark out the width of the chip to be cut by the chisel at each stroke. These scribers answer another purpose; their cutting is so true as to leave the two sides of the mortise so perfectly smooth as to require no further trimming or polishing.

The next process is to remove the block from the mortising machine to a circular saw, in order to have the four corners taken off, by which operation it is reduced to an octagonal shape. This saw being fixed into a table or bench, the workman has nothing more to do than to slide each log along the surface of the table, in the direction of the line marked out for the saw to cut it.

The next operation is to place the block upon the Shaping Machine. This is perhaps one of the most ingenious and most effective contrivances in the whole machinery of the wood-mills. It consists principally of two equal and parallel circular wheels moving on the same axis, to which one of them is firmly fixed, but on which the other is made to slide; so that these two wheels may be placed at any given distance from each other, and blocks of any size admitted between their two rims or peripheries. For this purpose, both rims are divided into ten equal parts, for the reception of ten blocks, which are firmly and immovably fixed between the two wheels. When the double wheel with its ten attached blocks is put in motion, the outer surfaces of the blocks, or those which are farthest from the centre, strike with great violence against the edge of a chisel or gouge fixed in a movable frame, which, being made to slide in a curved direction in the line of the axis, cuts those outward faces of the blocks to their proper curvature, which can be altered in any way the workman pleases, by a contrivance attached to the cutting tool. As soon as the tool has traversed the whole length of the block, or over the space contained between the two peripheries of the wheels, the machine is thrown out of the gear, and its prodigious velocity checked by a particular contrivance. The ten

blocks are then, by a single operation, and without removing them, each turned one fourth part round, and another fourth part of their surface brought outwards, which, being exposed to the cutting instrument traversing in the same direction as before, have the same curvature given to these new surfaces. A third side is then turned outwards, and, after that, the fourth and last side, when the whole ten blocks are completely shaped, and ten other octagonal logs applied to the peripheries to undergo the same operation.

The immense velocity with which the wheels revolve, and the great weight with which their peripheries are loaded, would make it dangerous to the workmen or bystanders, if, by the violence of the centrifugal force, any of the blocks should happen to be thrown off from the rim of the wheels; to prevent the possibility of such an accident, an iron cage or guard is placed between the workman and the machine.

The shell of the block being now mortised and completely shapen, the last operation is performed by the Scoring Machine, which, by means of cutters, scoops out a groove round the longer diameter of the block, deepest at the ends, and vanishing to the central hole for the pin on which the sheave turns. The intention of this groove or channel is to receive the hempen or iron strap which surrounds the block. The only thing that now remains for completing the shell, is the removal of the little roughnesses from the surface, and giving to it a kind of polish, which is done by the hand.

THE SHEAVES. The wood generally used for making sheaves is lignumvitæ, but iron or bell-metal have occasionally been substituted for this wood. An attempt was made to introduce sheaves of a kind of porcelain, which answered well enough for some particular purposes, but were not to be trusted in situations where they were liable to sudden jerks and irregular motions. In the navy they are almost invariably of lignumvitæ, a few perhaps of ebony. The machinery employed for making this part of the block consists of a Circular Saw, by which the log is cut into plates of the thickness required for the sheaves, according to their several diameters. These plates are next carried to a Crown Saw, which bores the central hole, and at the same time reduces them to a perfect circle of the assigned diameter. The sheave, thus shaped, is next brought to the Coaking Machine, a piece of mechanism not inferior in ingenuity to the Shaping Machine for the shells. It would be useless to attempt to describe by words the movements of this engine, but the effect of the operation is singularly curious. A small cutter, in traversing round the central hole of the sheave, forms a groove for the insertion of the coak or bush, the shape of which is that of three semicircles, not concentric with each other, nor with the sheave, but each having a centre equally distant from that of the sheave. The manner in which the cutter traverses from the first to the second, and from this to the third semicircle, after finishing each of them, is exceedingly curious, and never fails to attract the particular notice of visitors. So very exact and accurate is this groove cut for the reception of the metal coak, and so uniform in their shape and size are the latter cast in moulds, that they are invariably found to fit each other so nicely and without preparation, that the tap of a hammer is sufficient to fix the coak in its place. The coaks are cast with small grooves or channels in the inside of their tubes, which serve to retain the oil or grease, without which it would soon ooze out, and the pin become dry.

The sheave, with its coak thus fitted in, is now taken to the Drilling Machine, which is kept in constant motion. In casting the coaks a mark is left in the centre of each of the three semicircles. This mark is applied by a boy to

the point of the moving drill, which speedily goes through the two coaks and the intermediate wood of the sheave. A copper pin, cut from wire, of the proper length and thickness, is inserted into the holes thus drilled. And the sheave is then taken to the Rivetting Hammer, which is something like a small tilt hammer, and can easily be made to strike on the pin with greater or less velocity, according as the workman presses with more or less force on the treadle. The rivetting being performed, the next operation is that of broaching the central hole on which the sheave turns, by means of a steel drill or cutter.

The last process is that of turning a groove for the rope to run in round the periphery of the sheave, and this operation is performed by a lathe, which is so constructed, that while this groove is cutting round the rim of the sheave, another part of the engine is turning smooth the two surfaces or faces of the sheave; and this lathe can be made to adapt itself to sheaves of different diameters.

The shell and the sheave being now completed, there remains only the iron pin, which, passing through the two sides of the former, serves as the axis on which the latter turns within the mortise. These pins are also made, turned, and polished by engines for the purpose, so that, with the exception of strapping by rope or iron, the whole block is completed at the wood-mills. It may here be remarked, that the French, in the dock-yard of Brest, have long been in the practice of making blocks by machinery, but they have not attempted anything like a shaping machine, nor any substitute for it, the external shape of the shell being made entirely by hand; nor have they such a coaking machine as that invented by Brunell. The machinery at Brest is put in motion by horses. (See DOCK-YARD.)

BLOCKADE, in war, the shutting up of any place or port by a naval or military force, so as to cut off all communication with those who are without the hostile line.

There is, perhaps, no part of the law of nations which, in practice, presents so many perplexing questions as that which concerns the respective rights of neutral and belligerent states. No definite line of distinction has yet been drawn between the privileges of war and peace; and the consequence has been, that, in all the wars which have been waged in Europe, the general tranquillity of the world has been endangered by the jarring of these two different interests. It has commonly happened, too, that all these important questions have been agitated during a season of war; when the passions of the contending parties were keenly engaged in the dispute; when principles were already subverted; and when the minds of men, exasperated by the glaring infraction of acknowledged rights, were not in a state to agree on any system of general equity by which to regulate and reform the erring policy of states. In these circumstances, many points of international law, which appear to rest on the most obvious principles, and which are very clearly settled in the writings of civilians, have, nevertheless, been the occasion in practice of no small controversy, and have frequently involved nations in all the miseries of protracted war. This has been in some measure manifested in the case of the Rights of Blockade, respecting which, though no difference of opinion has ever prevailed amongst speculative writers, a controversy arose during the late contests in Europe, which, along with other points, ultimately involved Great Britain in a war with the neutral powers. We propose, in the course of the subsequent observations, to state, 1st, The general principles from which the most approved writers have deduced the rights of blockade; and, 2d, To give a short account of the differences which took place between the neutral and the belligerent states, respecting the extent of those rights.