An Illustrated Glossary of Technical (Continued from page 141.) CAISSON (in architecture), a kind of chest or flat-bottomed boat, in which brick or stonework is builded, and then sunk to the bottom of the river for forming the foundations. Some of the caissons which were used by Labelye for the erection of Westminster-bridge, contained above one hundred and fifty loads of fir CRAMPONEE (in heraldry), a cross cramponee (To be continued.) timber, of forty cubic feet to the load, and was is that which has a cramp at each end. CALATHUS (in ancient architecture,) a sort of basket, in which women anciently kept their work; and also a sort of cup used in sacrifices. The baskets whieh are on the heads of canephore are also called by this name, as well as the baskets on the heads of Jupiter Serapis, Juno of Lamos, Diana of Ephesus, &c. CONSUMPTION OF SMOKE.-It is well known to those who have paid attention to the subject, that wherever dense volumes of smoke escape from a chimney a great waste of fuel is taking place, as the necessary consequence of rapid and imperfect combustion. The high price of coal in London, and the southern and CALIDUCTS (in architecture), pipes or canals eastern districts generally, renders it of condisposed in or along the walls of houses for siderable importance that this waste should conveying hot air or steam to distant apart-not take place if there are means in existence ments from a common or central furnace, after to prevent it. It is thought there is a patent the manner of the ancients. This method has method of effecting this object which is atbeen adopted in modern buildings with much success and economy. The British Museum and several of the public offices are heated by this means. tended with much expense. The method we are about to explain has this advantage over the patent, it will cost nothing to make the experiment, and it is open to every manufacturer who wishes to save his coal and avoid poisoning his neighbours with smoke. Instead of putting coal on the fires every half-hour or so, a red state, be pushed to the further end of the as at present, let the mass of cinders, when in boiler near the fire, leaving a thin layer of red cinders covering the whole forepart of the firehole. Let this layer of fire be completely covered with coal, leaving the fire pushed backwards clear and bright. Let the damper be then half-closed so as to prevent the draught being too strong. The smoke from the burning coal in front will then pass slowly over the bright fire at the back, the carbon or combustible matter being consumed as it passes. The dark portions of smoke are nothing more than small particles of coal which only require to be passed through a strong heat to deprive them" of those qualities which render them such a nuisance where steam-engines are numerous. The only instance in which the plan was seen the engine was one of 10 or 12 horse power, tried was decidedly a successful one, for although the smoke emitted from the chimney was not more than is commonly seen issuing from the chimney of a cottage. No doubt many persons consider smoke as an article of little value, but let such persons observe the chimney of a gas-manufactory, and they will soon perceive that gas-makers know to well what smoke is worth to let it go up their chimneys. They take care to extract all the carbon from their smoke before they let it escape. Why should not silk, cotton, and woollen manufacturers do the same? They would find it profitable.Patent Journal. On Polishing Wood, Evory, Horn, This may be applied either to furniture, or to and Tortoiseshell. shall be of about the thickness of honey. work running in the lathe, by means of a piece of clean cloth, and as much as possible should then be rubbed off by means of a clean flannel, or other cloth. Bees'-wax alone is often used: POLISHING IN THE LATHE. Good work does upon furniture it must be melted by means of not require much polishing, for the beauty of it a warm flat-iron; but it may be applied to depends more on being executed with tools work in the lathe, by holding the wax against properly ground, set, and in good order: the it, until a portion of it adheres; a piece of work performed by such tools will have its sur-woollen cloth should then be held upon it, and face much smoother, its mouldings and edges the lathe turned very quickly, so as to melt much better finished, and the whole nearly the wax; the superfluous portion of which polished; requiring, of course, much less sub- may be removed by means of a small piece of sequent polishing than work turned with blunt wood or blunt metal, when a light touch with a tools. (This is often the case in that done by clean part of the cloth will give it a gloss. A amateurs and workmen who have not proper very good polish may be given to mahogany by conveniences for grinding and setting their rubbing it over with linseed oil, and then holdtools.) ing against it a cloth dipped in fine brick-dust. One of the most necessary things in polish- Formerly, nearly all the mahogany furniture ing is cleanliness; therefore, previous to begin-made in England was polished in this way. ning, it is as well to clear the turning-lathe, or work-bench, of all shavings, dust, &c., as also to examine all the powders, lacquers, linen, flannel, brushes, &c., which may be required, to see that they are free from dust, grit, or any foreign matter. For further security, the polishing-powders used are sometimes tied up in a piece of linen, and shaken as through a sieve, so that none but the finest particles can pass. Although, throughout the following methods, certain polishing-powders are recommended for particular kinds of work, it must be understood, that there are others applicable to the same purposes, the selection from which remains with the operator; only observing this distinction, that when the work is rough, and requires much polishing, the coarser powders are best; but, on the contrary, the smoother the work, the less polishing it requires; consequently, the finer powders, in the latter case, are preferable. Soft wood, though nearly the most difficult material, may be turned so smooth, as to require no other polishing than that produced by holding against it a few fine turnings or shavings of the same wood whilst revolving, this being often sufficient to give it a finished appearance; but, when the surface of the wood has been left rough, it must be rubbed smooth with polishing paper, constantly varying the position of the hand, otherwise it would occasion rings or grooves (if they may so be called) in the work. When the work has been polished with the lathe revolving in the usual way, it appears to be smooth; but the roughness is only laid down in one direction, and not entirely removed, which would prove to be the case by turning the lathe the contrary way, and applying the glass-paper; on which account, work is polished best in a pole-lathe, which turns backwards and forwards alternately; and therefore it is well to imitate that motion as nearly as possible. Mahogany, walnut, and some other woods, of about the same degree of hardness, may be polished by either of the following methods:Dissolve, by heat, so much bees'-wax, in spirit of turpentine, that the mixture, when cold, Hard Woods.-These, from their nature, are readily turned very smooth; fine glass-paper will suffice to give them a very perfect surface: a little linseed oil may then be rubbed on, and a portion of the turnings of the wood to be polished may then be held against the article, whilst it turns rapidly round, which will, in general, give it a fine gloss. Sometimes a portion of shell-lac, or rather of seed-lac, varnish is applied upon a piece of cloth, in the way formerly described. The polish of all ornamental work wholly depends on the execution of the same, which should be done with tools properly sharpened: and then the work requires no other polishing but with a dry hand-brush, to clean it from shavings or dust, this trifling friction being sufficient to give the required lustre. Ivory, or bone, admits of being turned very smooth; or, when filed, may afterwards be scraped, so as to present a good surface. They may be polished by rubbing them first with fine glass-paper, and then with a piece of wet linen cloth dipped in powdered pumice-stone this will give a very fine surface, and the final polish may be produced by washed chalk, or fine whiting, applied by a piece of cloth wetted in soap-suds. Care must be taken in this, and in every instance where articles of different fineness are successfully used, that previously to applying a finer, every particle of the coarser material be removed; and that the rags be clean and free from grittiness. Ornamental Work must be polished with the same materials as plain work; using brushes instead of linen, and rubbing as little as pos sible; otherwise, the more prominent parts will be injured. The polishing material should be washed off with clean water, and, when dry, may be rubbed with a clean brush. Horn and Tortoiseshell are so similar in their nature and texture, that they may be classed together, as regards the general mode of working and polishing them. A very perfect surface is given by scraping; the scraper may be made of a razor-blade, the edge of which should be rubbed upon an oil-stone, holding the blade nearly upright, so as to form an edge like that of a currier's knife; and which, like it, may be sharpened by burnishing. Work Electric Light. when properly scraped is prepared for polishing; to effect this, it is first to be rubbed with a buff, made of woollen cloth, perfectly free from grease; the cloth may be fixed upon a stick, to be used by hand; but, what the work- THE electric light in a continuous stream obmen call a bob, which is a wheel running in tained by the new battery of MM. Lemolt and the lathe, and covered with the cloth, is much Archereau, forms a new era in artificial lightto be preferred, on account of the rapidity of ing. This light, the first trials of which have the operation: the buff is to be covered either been recently made at 42, Passage Jouffroy, with powdered charcoal and water, or fine has been introduced by the managers of the brick-dust and water; after the work has been theatre in the Palais Royal, for illuminating made as smooth as possible with this, it is fol- the last scene of the Banc d' Huitres. The lowed by another buff, or bob, on which intensity of this light is such, that it quite washed chalk, or dry whiting, is rubbed; the eclipses by its splendour the footlights comb, or other article to be polished, is and the chandeliers, which actually cast moistened slightly with vinegar, and the buff and whiting will produce a fine gloss, which may be completed by rubbing it with the palm of the hand, and a small portion of dry whiting, or rotten-stone. a shadow on the back of the scene. By the help of an ingenious mechanism in connexion with the poles of the battery, the actor Leménil, placed in front of the stage, produced from a binocle two lights, whose glowing brightness illuminated the spectators as with a sunbeam; then one of these same bright MASONS' PROVIDENT INSTITUTION.-The lights starting from a point in the second galsecond annual meeting of the above excellent lery, inundated the scene of the Field of the institution was held on Tuesday evening, Fe- Cloth of Gold, with a blaze of light like the bruary 1st, at the City of Westminster Me- brightest daylight, to the great admiration of chanics' Institution, Mr. Wm. Haysom in the the spectators. The important point in the chair, for the purpose of receiving the com- perfecting of this invention, consists in giving mittee and auditors' report for the past year, to the electric spark a continuity of splendour which left a balance in the hands of the trea- and duration not hitherto obtained, but which surer (Mr. Wm. Freeman) of £209 17s. 5d., is now destined to applications on a large including handsome donations from Mr. John scale: for example, to lighting large squares Foot, Messrs. H. and J. Lee, Sir De Lacy and public avenues, theatres, signals, teleEvans, M.P., and others. Thanks having been graphs, and even to the studio of the painter, voted to the late direction, a committee of twenty-five was appointed for the ensuing year, with instructions to take into consideration the propriety of announcing an election for one or more candidates for aid from the funds at the next half-yearly meeting. ANCIENT CARVINGS.-About twenty little carvings in ivory, which were discovered lying on some of the bassi-relievi brought to this country from Nineveh by Mr. Layard, have been added to the national treasures in the British Museum. They are on a small scale-about four inches by two and a half; the greater portion of them resembling strictly Egyptian types rather than Assyrian. Indeed, with scarcely any variation, they correspond with all other Egyptian relics that we know of. The few of Assyrian characters will be a great acquisition-showing, as they do, the state of such Art at that early period. They are well carved, in low relief. A series of drawings is being made from them for publication. is for the winter season, since the electric light does not interfere with colours. The electric light of the diameter of a large pea, and thirty times smaller than a gas light, equals more than 300 jets of gas, and, relatively to its volume, equivalent to a mass of gas 9,000 times more considerable. As to its splendour, it surpasses, whatever be their number, all hydrogen lights, and projects its rays three times the distance. With the aid of an apparatus of only 30 square centimetres, M. Lemolt is engaged in making comparative experiments, so as to replace, with a triple advantage of range and intensity, every species of artificial light, even that obtained by the most powerful lighthouse reflectors. An electric ray emanating from this apparatus, and glancing on one of the terraces of the Passage Jouffroy, at the elongation of the two Rues Viviennes, gave sufficient light to allow of a placard being read placed on the steps at the entrance of the Palais Royal, a distance of 1,100 yards. M. Lemolt has also by concentrating the rays of electric light by means of a lens, inflamed at various distances several combustable substances. NEW GALLERY.-To facilitate the education of the people in the art of design, "a new gallery" has been opened in Newman-street, Oxford-street, in a house well adapted for the purpose. Mr. Baily, the sculptor, has provided the gallery with its chief ornaments and The Chancellor of the Exchequer has acceded means of instruction, by a munificent gift of to a grant of £4,200 to the Print Department of casts and models from the antique; including the British Museum for the purchase of a colthe Apollo," ,""Venus de Milo," and "Gla- lection of rare English portraits, &c.-and of diator." The institution was open on Wednes- an extensive selection from the Aylesford Colday sennight, with a discourse by Mr. James lection of Rembrandt's Etchings, which will Matthews Leigh, the artist, on the subject of render our national collection of the works of the earliest periods of art, particularly the that master equal to any of the kind in Grecian schools. Europe. |