from all true woods. The colours and hardness of the two parts differ very materially, and the following are the distinctive names of three.

The Areca catechu, or betel-nut palm, is remarkably perpendicular; it grows to the height of about thirty feet, and rarely exceeds four or five inches diameter: it bears a small tuft of leaves, and the fruit is in clusters like grapes. The betel-nut is chewed by the Indians along with quicklime, and the leaf of the piper-betel, in the manner of tobacco. The general colour of the wood is a light yellow brown; the fibres are large, hard, and only a few shades darker than the cementitious portions.

The Cocos nucifera, or cocoa-nut palm, flourishes the best in sandy spots near the sea-beach; it sometimes grows to ninety feet in height, and three feet in diameter, but is generally less; it is rarely quite straight or perpendicular, and has broad pendent leaves, from twelve to fourteen feet long, in the midst of which is a sort of cabbage, which, as well as the fruit, the cocoa-nut, is eaten; the husk of the nut supplies the material for coir-rope, &c. No part of this interesting tree is without its grateful service to the Indian: the leaves are used for making baskets, mats, and the covering of his dwelling; he also obtains from this tree, oil, sugar, palm-wine, and arrack; and, although the upper part of the trunk is soft and stringy, the lower supplies a useful wood, the fibres of which are of a chesnut brown, and several shades darker than the intermediate substance; the wood is employed for joists, troughs for water, and many purposes of general carpentry, &c. The Asiatic Society has specimens marked, male, 1st, 2nd, 3rd, 4th sorts, and the same number of female varieties; no marked distinction is observable between them.

The Niepere palm is much darker than either of the preceding kinds; the fibres are nearly black, and quite straight, and the cement is of a dark brown; but in other varieties with these black fibres, the softer part is very light-coloured, and so friable that it may be picked out with the fingers. Colonel J. A. Lloyd informs us that, at the Isthmus of Darien, they use the fibres of some of the palms as nails for joinery-work.

Palmyra-wood, or that of Borassus flabelliformis, says Mr. Laird, is largely imported into Madras and Pondicherry, from the Jaffna district at the northern part of Ceylon, for the construction of flat roofs; the joists of which consist of two slabs, the third or fourth part of the trees, bolted together by their flat sides so as to constitute elliptical rafters, They are covered first with flat tiles, and then with a white concrete called Chunam, consisting of shell-lime, yolks of eggs, and Jaggree, (sugar,) beaten together with water, in which the husks of the cocoanuts have been steeped.

The prickly pole (Cocos guianensis) of Jamaica, &c., a palm growing forty feet high, and of small diameter, is said to be very elastic, and fit for bows and rammers. The palm-woods are sparingly employed in England, for cabinet and marquetry work, and sometimes for billiard cues, which are considered to stand remarkably well; they are also turned into snuff-boxes, &c. The smaller kinds are imported

under the names of Partridge canes, (called also Chinese or fishing canes,) Penang canes, from the island of that name, and some others, for walking-sticks, the roots serving to form the knobs or handles. The knobs of these sticks exhibit irregular dots, something like the scales of snakes; these arise from the small roots proceeding from the principal stem, which latter shows dotted fibres at each end of the stick, and streaks along the side of the same.

The twisted palm-sticks are the central stems or midribs of the leaves of the date palm; they are twisted when green, and stretched with heavy weights until they are thoroughly dry: they are imported from the Neapolitan coast, but are considered to be produced in Egypt. The shells of the cocoa-nut and coquilla-nut, and the kernels of the areca or betel-nut, and of the corosos or ivory-nut, have likewise their uses in our workshops.-Holtzapffell on Turning.

INDIAN RUBBER PAVEMENT.

ALTHOUGH We have long been sensible of the versatility of Indian rubber, we never, even in our most abstracted moods, contemplated the feasibility of its adaptation to the purposes of paving. Here, however, we have it not merely in the shape of paving-blocks, but in that of planks for boat-building, and ship-linings to prevent splintering from cannon shot. It appears that the paving has been applied in stables and other places with every success. In the stables of Sir Francis Collier, at Woolwich, the plan has been for a considerable time in use; and from what Sir Francis Collier says, it appears to have given every satisfaction.-Artizan, No. 7.

TESSELLATED PAVEMENTS.

IN 1840, Mr. Prosser, of Birmingham, discovered that if the material of porcelain (a mixture of flint and fine clay) be reduced to a dry powder, and in that state be subjected to strong pressure between steel dies, the powder is compressed into about a fourth of its bulk : it then undergoes a process of semi-vitrification, and is converted into a compact solid substance, of extraordinary hardness and density; much less porous, and much harder, than the common porcelain, uncompressed. This curious, and, as it has since proved, very important discovery, was first applied to the manufacture of buttons, to supersede those of mother-of-pearl, bone, &c. The buttons thus stamped out of porcelain powder are capable of resisting any pressure to which they are subject in use, and are more durable, as well as cheaper, than buttons of the materials ordinarily used.

The applicability of this ingenious process to the manufacture of tesseræ for pavements soon afterwards occurred to Mr. Blashfield, who made arrangements with Messrs. Minton and Co. (the manufacturers appointed to work Mr. Prosser's patent), for a supply of small cubes made according to the new process; these he submitted to various trials and experiments, and, having found them in every respect suitable for the purpose, he has recently, in conjunction with Messrs. Wyatt, Parker, and Co., carried on the invention on an extensive

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scale. Tessera of various colours and form-red, blue, yellow, white, black, brown; quadrilateral, triangular, rhomboidal, hexagonal, &c., have been manufactured on this principle in large numbers; pavements of considerable extent have already been constructed with them; and they have been found to possess the following advantages: :

First, being formed in similar steel dies, they are of uniform size and shape, so that they can be fitted together accurately in the laying down of the most complicated designs. Secondly, being all composed of the same material, variously coloured, they are all of precisely equal hardness, so that pavements made with them are not liable to fall into hollows in use. Lastly, owing to the effect of the intense pressure under which they are made, they are quite impervious to moisture, of a flinty texture throughout, and, in a word, to all intents and purposes absolutely imperishable. In these several respects, their superiority to the Roman tesseræ, (which, as we have seen, were shaped imperfectly by hand, and differed from each other in hardness,) must be manifest to the reader. Nor less conspicuous is the superiority of the modern process of uniting the tessera to form pavements. For this purpose, instead of spreading the cement on the surface to be paved, and laboriously setting each single tessera in it, (according to the directions of Vitruvius), the pavement is first put together, face downward, on a smooth surface, so that the tesseræ find their level without any trouble to the workman: and, as soon as a sufficient portion of the design is finished, it is backed with fine Roman cement, which is worked in to fill the crevices between the tesseræ : the pavement is thus formed into smooth flat slabs of convenient size, according to Mr. Singer's method, and these are laid down on a foundation properly prepared in the usual way.

One peculiar feature of this process is, that private persons, if so inclined, may set out their own pavements in the coloured tesseræ, leaving it for a workman afterwards to cement and lay down the slabs. Fine mosaic work for the tops of tables, for illuminated monuments, &c., may be made in the same manner with a superior kind of tesseræ, glazed on the surface, and richly ornamented in gold and colours. Pavements thus constructed are singularly beautiful. The outline of the design strikes clearly and sharply upon the eye, and the brilliant colours of the tesseræ are reflected from the level surface, uninterrupted by those broad uneven lines of cement, which, in the Roman pavements, detract so much from the general effect. The truth of every line and angle in the figure, and the just proportion of all its parts, however complicated and various, impress the mind with an agreeable sense of order and precision. Such, indeed, is the exactness and facility of the workmanship in these pavements, that the oblique and intricate intersections of the Mauresque designs are as readily executed as the simple rectangular patterns of the Pompeiian style. Even the scrolls and twisted guilloches, the quaint emblematical devices, and grotesque representations of horses, warriors, &c., found in the most elaborate of the Roman pavements, may be accu

rately imitated with the new stamped tesseræ.-Magazine of Science, No. 211.

PATENT ROAD AND STREET CLEANSING MACHINE.

THIS Machine, which is now in operation in Regent-street, and other parts of the metropolis, is the invention of Mr. Whitworth, of the firm of Messrs. Joseph Whitworth and Co., engineers, at Manchester, where it has been employed for several months past. The principle of the invention consists in employing the locomotive motion of rotatory wheels, moved by horse or other power, to raise the loose soil from the surface of the ground, and deposit it in a vehicle attached.

The apparatus for this purpose consists of a series of brooms suspended from a light frame of wrought iron, hung behind a common cart, the body of which is placed near the ground for greater facility in loading. As the cart-wheels revolve, the brooms successively sweep the surface of the ground, and carry the soil up an inclined plane, or carrier-plate, at the top of which it falls into the body of the cart. By the aid of this machine, the three operations of sweeping, loading, and carrying, are not only carried on simultaneously, but, as it were, blended in one operation; whilst each is so far simplified as to render the combination less complex and protracted than the single operation of either sweeping or loading by the usual mode. When going at the rate of only two miles an hour, with brooms three feet wide, the patent machine will clean nearly sixty superficial square yards per minute. This is about the average rate of work done by thirty-six men, Provision is made for letting off the water collected in the cart by means of a pipe, having its interior orifice some inches above the level of the mud after settlement. The cart when full is drawn to the side of the street, at some distance from a sewer-grid, and the pipe-plug being withdrawn, the water flows into the channel. By a slight modification of the original form of the machine, it is enabled to sweep close up to the curb-stone along the side of the street. The action of the brooms is regulated by a series of weights, which counterbalance a certain portion of the sweeping apparatus, and relieve the pressure of the broms on the ground. The brooms, with the entire apparatus, may also be raised from the ground, by means of a handle turned by the driver, whenever it is necessary to discontinue sweeping; as when the cart is full, or the surface obstructed. The same handle will raise the sweeping apparatus into the horizontal position, when access is required to the hinder part of the cart for the purpose of unloading.

The Machine has been worked on every kind of street surface,the round and square set stone, the macadamized road, and the wood pavement. Its peculiar advantage, as applied to wood pavement, is that it prevents the slippery state of the surface so much complained of. The wear of the brooms, which was at first considerable, has been diminished more than one half, by the action of the regulating weights. A product of South America, called by the Portuguese

Piassava, forms an excellent material for the beard of the brooms, having great pliancy and strength combined, and also a remarkable degree of durability.

An indicator, attached to the sweeping apparatus, shows the extent of surface swept during the day, and acts as a useful check on the driver. The cart is drawn by two horses. The economy effected by the contrivance is stated to be very considerable. The average of the present rate of cleansing varies from 3s. 6d. to 5s. per 1000 yards. By the aid of the patent Machine, it will be generally reduced to about 18.; less on pavement (wood or stone,) and rather more on macadamized roads. In London, however, the expense will be greater, owing to the low value of manure, and the cost of transport, which varies from 1s. to 1s. 6d. per ton.

NEW BRICK AND TILE-MAKING MACHINE.

A MODEL of Mr. Hunt's Machine for Making Bricks and Tiles has been exhibited to the Institution of Civil Engineers, with several specimens of its produce. Its action was described to be, that the tempered clay is placed in a hopper, the front and back of which are formed by the peripheries of two drum-wheels covered by webs of endless cloth, which, in descending simultaneously, carry down a continuous supply of clay of the exact length and width of a brick, while a frame is projected forward at given intervals so as to determine and cut off the requisite thickness, which is received upon a pallet-board, brought forward by an endless chain. About 1200 bricks are made per hour, with the attendance of two men and three boys to attend to the machine.

A SPEAKING MACHINE.

AN ingenious mechanician at Hamburgh, named Faber, is stated to have invented a Speaking Instrument which imitates correctly the sounds of the human voice. It consists of an imitation in caoutchouc of the larynx, the mouth, and palate, and it is worked by the aid of bellows in the same manner as an organ. The inventor, by touching certain keys, can make the instrument speak (in German, of course), and even sing. The compass of the artificial voice is, however, very limited, and the sound rather disagreeable; but in subsequent trials the inventor hopes to overcome these defects. This invention, if the accounts can be relied on, is a great advance on any previous attempts of the kind, the highest attainment having been to produce two or three articulate sounds.

PROPELLING BALLOONS.

MR. MONCK MASON, who, it is known, has for some time been devoting his attention to the subject, has conceived the idea that the Archimedean screw, as it has been applied to move vessels through the water, may also be applied to move balloons through the air. He has, accordingly, submitted this idea to the test of experiment. has constructed a balloon somewhat in the shape of an egg.

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