FROM the history of scientific discovery, we are naturally led to detail the progress of the Useful Arts, that branch of knowledge which forms the closest alliance with the necessities and comforts of our species. In this humble department of our work, we cannot expect to witness those higher efforts of the mind which are so frequently displayed in the history of abstract science; but we shall frequently have occasion to notice some of the finest specimens of mechanical genius, and to admire that unwearied exertion of talent among artists of every class, and that perseverance in tracing a principle of construction through all its applications, which have contributed so much to abridge manual labour, to multiply the resources of industry, and to add to that enormous power which man already possesses over the material world.

Though the present state of the continent is highly unfavourable to the execution of this part of our plan, we shall endeavour to supply the de

ficiency of foreign intelligence, by a more copious account of the inven tions and discoveries which have been made in our own country, and by extending our arrangements for obtain ing articles of intelligence which have not appeared in any other work.

Though the block-machinery at Portsmouth was invented previous to the year 1809, yet as no account of it has yet been given to the world, except in one work which is newly published, we shall present our readers with an account of the singular me chanical process by which ships' blocks, of various kinds and sizes, are prepared for the navy. The machines by which this operation is effected are perhaps the most splen did and ingenious that have ever been erected in the whole world, and entitle their inventor to a high rank among the mechanics of the present age. In the year 1802, a patent for this invention was taken out by Mark Joambard Brunel, and, at the recommendation of General Bentham, government resolved to erect a set of

By means of four sawing machines, distinguished by the ingenuity of their construction, viz. the straight crosscutting saw, the circular cross-cutting saw, the reciprocating ripping saw, and the circular ripping saw, the timber is cut into parallelopipe. dons of the proper size for the blocks. The blocks in this rude state are taken to the boring machines, of which five are used for the purpose of boring a hole for the centre pin, and another at right angles to this, for the commencement of the mortice, which is to contain the sheave. From this machine, the blocks are carried to the morticing machine, of which three are used. This beautiful machine gives motion to several chisels in a vertical direction, which mortice out the cavities for the reception of the sheaves. A chip as thick as a piece of pasteboard is cut with the most wonderful accuracy, and these chips are prevented from accumula. ting, by means of a piece of steel at the back of each chisel, which thrusts them out. The chisels make from 110 to 150 strokes every minute. When the necessary cavities are morticed out, the blocks are taken to the corner-saws, (of which there are three,) by which all its angles are cut off in succession, by means of a circular saw mounted on a maundrel.

When the blocks are thus sawn into a polygonal figure, they are carried to the shaping engine, the object

of which is to form the outside of the blocks to the segment of a large circle. For this purpose, ten blocks are fixed by their extreme ends between the rims of two equal wheels fastened upon the same axis. These wheels are then made to move round with immense rapidity, so as to bring the blocks successively against the edge of a fixed gouge, which thus cuts them to their proper curvature. A progressive motion is also given to the gouge, in order to give the block its proper curvature in a direction at right angles to the planes of the wheels between which they are fixed. When one side of the blocks is thus shaped, all the ten blocks, by an instantaneous movement are turned a quarter round, so as to expose another side to the gouge, which shapes them as formerly, and in this way the third and the fourth side are formed of the proper shape. Three of these engines are used for blocks of different sizes.

The blocks are now taken to the scoring engine, which is intended to form the score or groove round the largest diameter, for the reception of the ropes or straps of the block.

By these machines are formed the shells of the blocks, which are polished and finished by manual labour. The next part of the operation is the formation of the sheaves, which are made of lignum vitæ. By means of two saws, the straight saw and the circular saw, the tree of lignum vitæ is cut into pieces approaching to a circular shape, and nearly of the thickness of the intended sheave. These pieces are carried to the crown or trepan saw, with a centre-bit in its axis. When the piece of wood is properly fixed, the saw is applied against the wood, and cuts it into a circular form with great rapidity,

while it at the same time forms a hole exactly in its centre.

The blocks are now taken to the coaking engine, a machine remarkable for the ingenuity which it displays. It is employed to form in the centre of the sheave a cavity of the shape of three small semicircles, arranged at equal intervals round the centre hole formed by the crown saw. This cavity is intended for the reception of the coak, or metal bush, which is made of copper, zinc, and tin, and cast of the same shape as the cavity now formed. When the coaks are inserted into the sheave, the drilling machine is employed to perforate the three semicircular projections of the coaks and the wood beneath, in order to fasten the coaks by copper pins put into these holes. The pins being placed in the holes then drilled, are rivetted by means of the rivetting hammers, which are made to strike a heavier blow at the end of the operation. The sheave is now carried to the broaching engine, and fixed to an axis revolving vertically. A broach or cutter is brought down into the hole in the centre of the coak, for the purpose of enlarging it, and making it truly cylindrical. The sheaves are then finished by the face-turning lathe, which has a sliding rest that supports the turning tool, and moves it slowly across the face of the sheave. As the face of the sheave which is thus turned is composed partly of the metal coak, and partly of wood, and as it has been found by experience that different velocities are required for turning wood and metal, the machine has a very ingenious contrivance for changing the velocity when the tool passes from the wood to the metal. Besides the machines which we have enumerated, there are other four; viz. the turning lathe, for turning the

iron pins; the polishing engine, for polishing the iron pins; the machine for boring very large holes in any po sition, which is used for the largest sizes of blocks; and the machine for making dead eyes.

No fewer than 200 sorts and sizes of blocks are constantly making by these machines, and more than 1420 blocks are manufactured in the course of a single day. Such of our readers as may be induced by the preceding description to inquire further into the subject, will find their curiosity amply gratified by consulting the ar ticle BLOCK MACHINERY in the Edin burgh Encyclopædia, which is the first account that has been given of that curious operation, and which is illustrated with five perspective drawings of the principal machines.

A new portable bridge has been invented by Mr James Elmes, Cheapside, London. Bridges of this construction may also be rendered per manent. A description and drawing of this invention will be found in the Philosoph. Magazine, vol. 53, p. 12

A method of hastening the matu ration of grapes has been proposed by John Williams, Esq. For this purpose, a ring of bark, from 1 to 2 eighths of an inch wide, is cut from the trunk of the vine, or from the smaller branches when the trunk is large, so as just to expose the alburnum without injuring it. The shoots which come from the root of the vine, or from the front of the trunk, situated below the incision, must be removed as soon as they ap pear. In every case in which Mr Williams tried this experiment, he invariably found that the fruit not only ripened earlier, but that the berries were considerably larger and more highly flavoured than usual. Mr Williams supposes, that, by cutting through the cortex and liber without

wounding the alburnum, the descent of that portion of the sap which has undergone preparation in the leaf is obstructed, and confined to the branches above the incision, and that the fruit is thus better nourished and brought earlier to maturity. Mr Williams supposes that this practice may be extended to other fruits, but particularly to figs. The preceding method furnishes an explanation of the well-known fact, that vineyards improve every year by age till they are fifty years old, and that the fruit is brought sooner to maturity in old El vines. For when the vines become old, the rigidity of the vessels obestructs the circulation of the descending sap, and thus produces the same effect which is obtained by an excision of the bark. See the Transactions of the Horticultural Society, vol. i.

A method of painting linen cloth in oil colours, so as to be more pliant, durable, and longer impervious to water than in the usual mode, has been discovered by Mr William Anderson, master painter of his Majesty's dockyard, Portsmouth. The ingredient which he employs is perfectly simple, being a solution of yellow soap, and the composition is thus made :-To one pound of soap is added six pints of water in a vessel over the fire; in a few minutes after the boiling of the water, the soap will dissolve; whilst hot, it is to be mixed with oil paint, prepared as hereafter directed, and is then fit for immediate use. The above quantity of soap solution will be sufficient to mix with one hundred weight of paint: the first coat to be laid upon the canvas must be entirely of this composition, without first wetting the canvas in the usual A very small proportion of it, or none, is necessary in the second

way.

coat, and the third coat should be of oil-paint alone. The paint is made in the following manner :-To 96 pounds of English ochre, ground in boiled oil, are added 16 pounds of black paint, being one-sixth in proportion of the ochre; this when mixed forms an indifferent black. The solution, made of one pound of soap and six pints of water, is to be added to this paint, and well united with it and without the canvas being previously wet, this composition is to be laid upon the canvas as stiff as can conveniently be done with the brush, and this first coat will form a tolerably smooth surface. The second coat is to be formed of the same proportion of English ochre and black, without any soap solution, and the third or finishing coat must be done with black paint as usual. This method has met with such general approbation, that it is employed for all the canvas in his Majesty's dock-yards, and produces a saving of one guinea upon every hundred yards of canvas which is thus painted.

The silver medal of the Society for the Encouragement of Arts, Manufactures, and Commerce, was voted to Mr Anderson for this invention. See the Transactions of the Society for 1807 in the Philos. Magazine, vol. xxxiii. p. 151.

A methodofraising large stones that are deeply sunk in the earth has been invented by Mr Robert Richardson of Keswick. This effect is produced by the power of a tackle of pullies combined with a windlass. The tackle is fixed to the top of the stone by a cylindrical iron plug, which is simply driven into a cylindrical excavation in the stone of the same shape; the windlass is then turned, and so firmly does the plug adhere to the stone, that it is immediately raised from the

ground, even when it is above four tons in weight. It seems rather difficult to explain the cause of the firm adhesion between the plug and the stone, as the plug is driven into the opening merely by a few blows from a hammer; but we imagine that it arises partly from the great friction between the plug and the stone, and partly from the plug being pressed more against one side of the cavity than another. By this valuable invention, two men can raise as many stones as twenty men could do in the usual way.

The silver medal of the Society of Arts was voted to Mr Richardson for this invention. A drawing and description of the machine will be found in the Transactions of the Society for 1808.

Mr James Pilton, Chelsea, has invented a new fence made of tort elastic wire, which becomes invisible at a comparatively short distance, and is calculated for pleasure grounds. The main wires are drawn out to the thick ness of a common quill, and continuous strings of these are inserted horizontally through upright iron stanchions. The interval between the strings is about nine inches, and that between the stanchions seven feet. The horizontal wires, in a state of tension, are fastened to two main stanchions at the extremity of the fence, passing at freedom through holes drilled in the intermediate stan

chions. The tension of every hori zontal wire is preserved by the superior stability of the extreme stanchions, on the construction of which, and the mechanism of the wire work, the resistance of the whole, as a barrier against heavy cattle, depends. When the extent of the fence is great, the main stanchions are relieved at expedient distances by other principal stanchions. An improved mode of

joining the horizontal wires qualifies every part of the length to bear the highest degree of tension. This fence has been used at the royal pleasure grounds at Frogmore, and in various parts by the nobility and gentry. When three feet six inches high, it is found sufficient to exclude the largest and strongest kinds of grazing stock. When raised to the height of five feet six inches, it is sufficient for parks containing deer, which have never been known to leap over it. When it is employed to keep lambs out of plantations, perpendicular wires com paratively slight are interwoven upon the lower horizontal ones. See Phil. Magazine, vol. xxxiii. p. 270.

An improved telegraph has been invented by Major Charles Machardy of the island of Jersey. The object of this telegraph is intended to express numbers which may be seen at à distance, and to which words may be referred at pleasure. The num ber of combinations may be carried to forty thousand, which exceeds by many thousands all the words in the English language. Words may thus be forwarded as fast as they can be looked for in a dictionary; and even whilst only an equal number of letter could have been communicated by the present mode. Another advan tage arising from the use of words telegraphic communications is, that by words of the same meaning in differ ent languages having the same nu ber, correspondence may be carried on from one language into another, which, although not grammatically correct, would yet be sufficiently in telligible.

The silver medal of the Society of Arts was voted for this invention. See the Transactions of the Society for 1808, in the Philos. Magazin, vol. xxxiii. p. 348.

Thomas Andrew Knight, Esq