Kitabı oku: «British Manufacturing Industries: Pottery, Glass and Silicates, Furniture and Woodwork.», sayfa 9
The soluble silicates are frequently used as bonding materials in the manufacture of artificial stone and cement, very good results having been attained. The objection, however, to their employment for these purposes is the expense of the material of which they form a constituent part, and it seems almost impossible ever to bring it into competition with dressed natural stone. But for ornamental purposes, from the plastic nature of the substance when in the wet state, it can be pressed into moulds, and wherever plaster mouldings are admissible, no doubt this material would be useful for certain kinds of ornamentation. Some years ago, Mr. Ransome, of Ipswich, after having made his artificial stone with sand and silicate of soda, heated it in ovens, so as to produce a hard and semi-vitrified mass. A church, the mouldings of which are made of this stone, may be seen at the bottom of Pentonville Hill, London; and certainly as to durability, there is no doubt that the substance has answered very well. But from difficulties in manipulation and other reasons, that gentleman gave up this method of making artificial stone, and is now working another process which yields far better results. Silicate of soda is mixed with sand (generally Aylesford sand), and after the mixture is moulded and dried, it is exposed to the action in vacuo of chloride of calcium in solution. Whether the whole mass is placed in a vacuum chamber and then charged with chloride of calcium; or whether a vacuum is formed on the under side of the substance, and the chloride of calcium solution caused by suction to filter through it, is uncertain. However, whatever be the manipulative processes, the result is the same, and appears to be extremely satisfactory.
Soluble silicates produce very remarkable results when mixed with certain substances. If silicate of soda or potash be mixed with white lead, in a very short time it sets into a hard substance, just as does plaster of Paris when mixed with water. If powdered pumice-stone or sand, in the proportion of eight parts to one of carbonate of lead, be mixed together with soluble silicate, a very hard and coherent mass is obtained, and there seems no reason why a mixture of this kind, in which pumice-stone is used, should not be employed for the purpose to which pumice-stone is usually applied. It would have the advantage of being easily moulded into forms, so as to suit mouldings, which might by it be much more accurately and expeditiously smoothed down (as in the case especially of picture-frame mouldings), than they can be by the ordinary pumice-stone.
Another very important application of soluble silicates is the rendering of wood incombustible. Many experiments have been performed which show that when wood is thoroughly impregnated to a depth of a quarter of an inch or more with silicate of soda, it will not flame, but will only char. Now, supposing that the constructive timbers of a house were worked, and then placed in suitable vessels and saturated with silicate of soda, they would then be rendered practically fireproof, or at least it would take a very prolonged exposure to heat to cause them to smoulder away, while at no period of this time would they burst into flame. From the peculiarly gluey nature of these soluble silicates, they do not penetrate readily into porous substances; it has therefore been suggested that the impregnation of the wood should take place in vacuum chambers, just in the manner that the creosoting process for preserving railway sleepers is at present performed. It is most certainly advisable that the wood should be worked before being exposed to the silicating process, for that would render it so hard, that it would considerably increase the cost of labour in cutting and planing it.
At the commencement of this article, it was stated that silicic acid, or silica, could be made soluble in water. Some very interesting experiments were performed by the late Dr. Graham, Master of the Mint, which gave rise to the discovery of the process of dialysis. If some silicate of soda be mixed with water, so that not more than 5 per cent. of silica be in the solution (rather less is better), and if some hydrochloric acid be then added in sufficient quantity to make the liquid distinctly acid, and the mixture be placed in a dialyzing apparatus, the chloride of sodium formed by the union of the chlorine of the hydrochloric acid with the sodium of the silicate of soda will pass out through this dialyzing membrane, leaving hydrated silica behind, which will remain in solution in the water with which the silicate was mixed. The dialyzing apparatus is constructed in the following manner; a sort of tambourine ring is made with gutta percha, in place of wood, from 8 to 10 inches or even more in diameter, the depth, being about 2 inches. Another ring of gutta percha, of about an inch deep or even less, is made so as to fit tightly outside the tambourine; a piece of vegetable parchment is then moistened and placed over the tambourine, and the thinner ring is pressed over it, so as to secure it tightly. This is the dialyzing vessel, and it is into this that the mixture of silicate and hydrochloric acid must be put. The solution should not be more than an inch deep in the dialyzing vessel, which is then made to float upon distilled water in a larger vessel of suitable size. The distilled water should be changed every day, until no precipitate can be obtained in it with nitrate of silver, and when this point is arrived at, all the chloride of sodium will have passed through the vegetable parchment into the larger vessel of water, and nothing but silicic hydrate will remain behind in solution. If this liquid be allowed to stand for some time, it will gelatinize, and later on the jelly will contract, becoming extremely hard, so that lumps of it, when broken, will in their fracture resemble that of flint. No doubt, at some future period, some one will discover a method of rendering this condition of silica useful in the arts.
Soluble silicates are very useful as detergents. A small quantity of silicate of soda mixed with hard water renders it valuable for washing purposes. Silicate of soda is also used in the manufacture of the cheaper kinds of soap. We can hardly speak of it as an adulteration, because it renders the soap with which it is combined much more powerful in its cleansing action. I suggest to those interested in the application of science to the arts, that this subject will no doubt well repay experimental investigations.
It is much to be wished that those engaged in this branch of art and manufacture, and who have some knowledge of chemistry, would turn their attention to getting a better and more perfect method of making coloured pot-metal glass. I have been engaged for some time, and still am engaged, in experiments to effect this object. But inasmuch as my engagements are very numerous, and I cannot give the proper time to it I desire, I therefore take the liberty of suggesting to others the ways in which I am working, that they may be able to arrive at good results more speedily probably than I shall be able to do. If sulphate of copper be mixed with silicate of potash, silicate of copper will be precipitated. Now, if this be carefully washed and dried, it will be a silicate of a definite composition, and I propose to use such silicates as these with ordinary glass mixtures, in order to impart the particular colour which the oxide employed has been already described as giving to the glass. Silicate of manganese is prepared in a similar way to the silicate of copper; silicate of cobalt, and other silicates, can be used as staining materials for colouring glass. These mixed in due proportion would give tints, and would, I do not feel the slightest doubt, produce colours with much greater certainty than they are now produced, and tints hitherto unknown could be made to the great benefit of the glass-painter.
FURNITURE AND WOODWORK
By J. H. Pollen, M.A., South Kensington Museum
I propose in the following pages to give some account of the materials used in making furniture, and of the arts applied to its decoration. From the earliest ages of society, when men moved about in tribes, they had in their tents of camels' hair simple necessaries, such as their wants required. Before people were gathered into distinct nations, or cities built with walls and gates, there were still certain human wants that must needs be supplied; and the objects that were needed to enable mankind to live with convenience and decency were found in their furniture. To this very day we may see Arab tribes wandering over sunny deserts, seeking pasturage, sowing here and there an acre of wheat or barley, or gathering dates. Their camels and dromedaries are their waggons, their horses are their friends, their families and those of others that make up their tribe are their only nationality. Yet they furnish in some sort the temporary homes which they shift from one spring of water to another, as the patches of grass or grain grow up and ripen. Their chief wants are, a cloth strained over three staves to make a house, mats or carpets to lie on, a few bowls to cook in, saddles of wood, and a few baskets or chests, made of light sticks fastened together.
In later periods of history and in more conventional states of society, we shall find this primitive type of furnishing carried out with growing splendour. In the West and in the East, in ancient and mediæval times, great rulers, though constantly in the saddle, have been followed by enormous trains of camp followers, by whom costly furniture, hangings, vessels of plate, and other luxuries, have been carried for the convenience of the leaders and warriors of moving hosts; and of course this splendour was the measure of the state and magnificence kept at home. The wealth or feudal state, shown in the furniture of old castles and palaces, extended not only to halls and rooms, but to dresses, and armour, weapons, the furniture of horses, tents, and other objects that could be carried on distant expeditions.
Ancient nations have been as well, and more splendidly, if less conveniently, provided with furniture for their houses than modern ones. It happens that there are distinct records of many kinds, showing what wealth and elaborate decoration some of the oldest races, such as the Assyrians, the Egyptians, the Persians, and the Greeks, bestowed on their thrones, beds, chairs, and chariots. Beds of silver and gold are mentioned in Esther i., and the curtains of the bed of Holofernes were covered with a canopy of purple and gold, with emeralds and precious stones (Judith x. 19; Esther i.). Modern princes in India continue to devote their jewels and gold to similar uses. It must be borne in mind also, that this kind of splendour is an investment of property in times and countries in which banks, insurance offices, government funds, and other organized means of investing money are unknown.
Silver, if not gold, has been used occasionally, not only in the East, but in Europe, for seats, tables, even the frames of pictures and mirrors. The royal apartments in Whitehall were completely mounted with hammered and filagree silver furniture in the seventeenth century. Carlyle records of Frederick the Great, that silver ornaments were kept in his palace, and turned to account under the exigencies of war. But of furniture generally, wood is the readiest and most proper material. It is handy, easily worked, light to carry about, and may be manufactured with or without decorations of carved work, or of any other kind. Hence, in giving an account, whether historical or mechanical, of furniture, I class it under the more general head of woodwork. Any other materials, either for the framing or ornamentation of furniture, are exceptional. The remarks now to be submitted to the reader will refer to wood that is manufactured, though I shall not enter on the interesting subject of wood structure, which has been applied to such noble and elaborate uses, and of which such splendid monuments of many periods still remain for us to study.
Most of the methods used for decorating woodwork made up into furniture are still in regular use, and the processes of putting it together are the same as they have always been. The reader may satisfy himself on this point any day by a walk in the Egyptian rooms and in the Nineveh galleries of the British Museum. In both these sections of that wonderful collection, there are remains of woodwork and of furniture, made of wood three or four thousand years old, such as stools, chairs, tables, head-rests or pillows, workmen's benches of Egyptian manufacture, fragments less complete of Nineveh make that have been portions of various utensils, and precious articles of sculptured and inlaid ivory that have been inserted into thrones and chariots. These pieces of furniture have been mortised together, or joined by dowels, dovetailed at the angles, glued, nailed, or, in short, made up by the use of several of these methods of junction at the same time. And no great changes have been introduced in the various ways of ornamenting furniture. The Egyptian woodwork was painted in tempera, and carefully varnished with resinous gums. It was inlaid with ebony and other woods, carved, gilt and, perhaps, sparingly decorated with metal ornaments. The Greeks inlaid chests and tables with carved ivory and gold, sometimes relieved with colour. The Romans, who made much furniture of bronze, cast, inlaid, damascened and gilt, made much more in wood, which they stained, polished, carved, and inlaid. Mediæval furniture was put together with mortises, tenons and glue, and was gilt and painted; the painting and gilding being laid on a ground prepared with the utmost care, and tooled and ornamented in the same way that bookbinders ornament leather. At a later period, a beautiful manufacture was carried on in various parts of Italy; a sort of mosaic in very hard stone, such as agate, lapis lazuli, and other precious materials. The Italians also used these beautiful stones inlaid in ebony. But the furniture most valued in modern times has been that which owes its name to Boulle, a French artist of the seventeenth century; and the marquetry, or wood mosaic surface decoration, which reached so high a standard of excellence during the last thirty years of the eighteenth century in France.
The former of these two classes of manufacture made, if not originated, by Boulle (and I am inclined to think that he was not the first maker), was a marquetry, or surface decoration, not composed of various woods, but of tortoiseshell and brass, with the occasional introduction of other metal, and with metal enamelled in blue and other colours. The materials principally in use, however, in Boulle marquetry are tortoiseshell and brass. In the older work, viz. that of the seventeenth century, the tortoiseshell is dark, and left in its natural hue. In later Boulle, called new Boulle, the tortoiseshell is reddened by colour, or by gilding laid under it. There is much grace and variety in the delicate arabesque designs in which one material is inlaid in the other. Parts of the surfaces are sometimes diapered, as a contrast to the free lines and curves of other parts. The inlaid surface of Boulle work is framed in by borders, cornices, or handles of brass or gilt bronze, giving a massive architectural character to the whole.
Thus if we look back to the history of furniture, not only will every kind of splendid material be found devoted to the manufacture or decoration of it, but the best art too of many different periods that money could command. It is in the late times of antiquity, and since the period of the Renaissance in modern times, that works of art have been kept on shelves or gathered into galleries. Many works of great masters, such as the chest of Cypselus, and the chairs of the great statues of ivory and gold, were prepared for celebrated shrines and temples in the cities of Greece. It was but the excessive wealth of great patricians in Rome and Constantinople that led to their becoming collectors, whether of sculpture, painting, or sumptuous silver plate. The chief object of rich and accomplished men in most ages of luxury and refinement has been, to make the house, its walls, ceilings, floors, and necessary or useful furniture, costly and beautiful. It was the same in the days of Donatello, Raphael, Cellini, and Holbein. Chests and trays were painted, together with gems, dies, brooches; table plate was modelled and chiselled; while chairs of wrought steel, or tables, cabinets, and other pieces of rich furniture, were either designed or carried into execution by these masters with their pupils and followers. In some instances, as, e.g., in that of the famous Pomeranian cabinet, in the Kunst Kammer in Berlin, a long list has been preserved of artists and craftsmen of note in their day, who combined to produce monumental examples of actual room furniture.
It cannot be denied that though great pains are taken and much expense is incurred in modern furnishing, the habits of the day lead rather to the search for comfort than for grace or beauty; and convenience rather than intrinsic value or artistic excellence. Nevertheless, a certain amount of decency and splendour is indispensable in both receiving and sleeping rooms; and though a house really well, that is beautifully, furnished is of rare occurrence, this is not for want of serious efforts, nor altogether to be laid to the account of unwillingness to spend money for such a purpose. Whether the "art of furnishing" or the desire to have what people require for use in their houses more becoming and beautiful, be a rising influence or not, it is certain that the "fancy" or ornamental furniture trade is of large and increasing importance, corresponding to the increased size and cost of modern London and country houses, compared with those built during the reigns of William III. and George IV. Every tradesman who has the pretension to repair chimney-pots, to whitewash, or paint house-fronts, ceilings, or offices, writes up the word "decorator," on his shop-front.
The Qualities required in Furniture
We may consider furniture under two broad divisions, that which is made to be handled and moved about, and that which is for use but not meant to be handled or moved. We may add a third division in the actual fixtures of the house, made by the joiner and meant to be ornamental fittings or completions to the builder's and carpenter's work.
Under the first head will be included light tables, chairs, couches, and other movable objects; under the second, cabinets, book-shelves, frames, mirrors, and so on; under the third head come flooring, panelling, window shutters, door-frames, stair-rails, &c.
1. Chairs, Tables, etc
The essential points in a well-made chair are comfort, lightness, and strength. Of course, as men and women are pretty much of the same proportion all over the world, chairs, of which the seat is about the height of the lower process of the human knee-joints, must be of the same height, or but slightly varied, in every country. From the habit that so many persons have of throwing their whole weight back and, as we are told, in some countries, of balancing their persons on the back legs of their chairs and inclining their legs in the direction of the chimneypiece, there is often an immense strain on the back joints of chairs. Whether we lean back or swing on them, the junction of the seats of chairs with the backs is always subject to severe trials; and on no article of furniture in common use is such good joinery required. It is worth while to look at the old wall paintings of the Egyptians, as they are given in Rossellini and the great French book of the 'Description de l'Egypte,' to see what capital workmanship those most ancient carpenters bestowed on their chairs. Those of the best and oldest periods are without connecting bars to the legs before or behind, all the strength of the construction being centred in the excellence of the joints of the seat with the back and legs; and in modern workshops, the highest skill is applied to ensure strength in these points of junction. If the wood is thoroughly dry, the mortises and tenons fitting perfectly, and the glue good, the different parts are so wedded together that the whole structure becomes one piece, as if nature had made a vegetable growth in that fashion, all the fibres of which have continuous and perfect contact with each other. If, however, there is a deficiency in any of these conditions, these joints fail. If the wood shrinks, or the tenons do not fit the mortises all through, or the glue is deficient, these various portions speedily come to pieces. Sofas, couches, and stuffed chairs are so much more massive in construction that there need be no risk of such a kind of disintegration.
The members of which a chair is made up may be either turned in the lathe, or left massive enough to allow of carving on the legs, backs, or round the framework of the seat. Turned work can be lightly inlaid with ivory, as that of ancient Egypt, painted, gilt, or mounted (lightly also) with metal.
The subjects of the carving may be either figures of men, horses, lions, or the heads and legs of such animals, acanthus leaves, and arabesques. Many of these ornaments have been used from ancient times, and revived at various historical periods. For modern rooms the lightest construction is most in place, and therefore carving should be compact in composition and delicate in execution, without prominences or undercutting that would interfere with comfort or be liable to breakage.
A certain architectural character is given to chairs by cutting flutings down the legs, or by borrowing other slight details from architecture. The upholstery of chairs will always be their most noticeable decoration, and this applies still more to lounging chairs and couches of all shapes and sizes, as the framework of them is so much less observable in proportion to their upholstered surfaces.
Tables, lampstands, &c., being generally, though not always, meant to be moved about, require as light a construction as is consistent with strength. The surface of all but small tables is beyond the dimensions of a single plank of wood. The outer and inner portions of a log or plank are of different fineness of grain, contain varying proportions of sap, and shrink in different degrees. Single planks of wood, therefore, can only be exceptionally used for table tops. Generally, they are made up of portions of planks selected with great care, grooved on the edges, with a tongue or slice of wood cut the cross way of the grain, uniting the planks about the middle of their thickness; the edges are then firmly glued together. If the surface is to be of wood which can be procured in large pieces of straight or continuous grain, such as mahogany, the wood is solid throughout; if of some rare wood or rare figured graining, such as the roots or wens of oak, this ornamental surface is laid on in thin slices with glue and heavy pressure. This is known as veneering. The surface is sometimes inlaid with ivory, metal, mother-of-pearl, slices of agate and other substances, as in the Boulle or marquetry work already alluded to.
The frame of the table is either a deep rail not far within the edge, or a thick pillar or leg or several legs collected, mortised into a broad expanding foot and supporting a spreading framework above, to which the top itself can be fastened, and stretching far enough all round in the direction of the edges to give a firm support.
The decoration of the top can only be superficial if the table is for use, and any decoration by carving, piercing, and so on, must be confined to the framework and the supports. These parts can be, and have been at all times decorated as the framework of chairs, and by very much the same kinds of ornament.
To tables of more modern periods, little galleries of pierced work or of tiny balustrades are sometimes added. They belong to the age of porcelain collectors, hoops, broad coat-skirts, and tea-parties, and are intended to save delicate wares from being swept to the ground. Side tables, and such as are made to support heavy objects, can be treated with more massive frame work and supports, and the carving and decorations will be bolder and larger accordingly.
2. Cabinets, etc
I will proceed to the second division of furniture, cabinets, bookcases, and other standing objects, which are more or less immovable. But shelves and china trays must be placed in secure parts of the room, if they are not actually fastened to the wall. The former must be strong to support the great weights laid upon them, and the supports or framework, which is all that would be seen, may be carved or decorated with surface or applied metal ornament. On a large scale, fittings of this kind belong rather to architectural woodwork. China holders, whether placed on the ground or fixed against a wall, are properly treated with shelves quaintly shaped on plain and light, pierced galleries or gilt decorations corresponding with the apparent lightness of pieces of porcelain. The wood and lac work cabinets of the Chinese; and the complicated, but not ungraceful, gilt mirror frames and flourishing acanthus work of the Italians, French, and Germans, of the last century, seem specially suited for showing off this gay and fragile material. The collector proper will probably place his treasures under glass, and with little regard to the framework of his cases. Here china and china stands are treated only as decorations.
As to cabinets, they are the most precious, if not the most useful of all pieces of furniture. They have generally been intended to hold family treasures, are not required to be moved, and have therefore been the richest and most decorated objects in the room. Cabinets are the legitimate descendants of the chests of former days containing bridal outfits and trinkets, or plate, jewellery, and other valuables. They were carried from town to country, from grange to castle. About the beginning of the sixteenth century, the personal habits of great men became less nomad, and their chests were no longer liable to be packed and moved away. These receptacles were mounted on stands at which height the lids could not be lifted, and doors were substituted. Drawers took the place of shelves or compartments, and every sort of ingenuity was applied to make these pieces of furniture quaint and splendid inside and out.
As to shape, it is contrary to their purpose of convenience and interior capacity, to make cabinets, cupboards, or other receptacles, with showy and spreading architectural details, such as cornices, architraves, columns, pediments, and the like. All these parts, which are laborious and costly in construction, are so many additions to its size, and make no more room inside to compensate for this expenditure. Cabinets should, in propriety, be as big and convenient inside as their size would lead us to expect.
On the other hand, the many fine examples made in the sixteenth and seventeenth centuries in this country, Holland, Germany, France or elsewhere, have been generally intended for rooms larger, higher, and with fewer pieces of furniture in them than those of our modern houses, not to speak of the massiveness of fireplaces and fittings with which they were in character. It is their age, and the connection, which we cannot help tracing, with old houses and bygone generations which give architectural cabinets an interest now.
In construction, the skill of the cabinet maker will be shown in the neat and convenient arrangement of drawers of various depths and sizes, shelves or repositories, so contrived as to turn the entire internal space to account. The most curious contrivances are often found in old German, English, and French cabinets, bureaux, secrétaires, and other varieties of this kind of furniture. Pediments, capitals of columns, and other parts of architectural fronts are made to open, and secret drawers stowed away with an ingenuity almost humorous. It is upon the fronts and stands that the skill of great masters of the craft has been bestowed. The large wardrobes, or "armoires," of Boulle are examples of great inventive and designing power, as well as the marquetry of Riesener and David, and the chiselled metal-work of Berain, Gouthière, and that of many English artists.
As in past times, and so in our own, it is on cabinets that the real triumphs of the cabinet maker's art are displayed.
3. Fixed Woodwork
Thirdly, the joiner's and cabinet maker's art plays an important part in the fixed furniture of the house, and the woodwork, such as flooring, doors and door-frames, panelling, chimneypieces, with the complementary decorations of hangings, whether tapestry, silk, or the more humble material of paper.
In this last division of furniture the work is that of joinery. There is no great demand for constructive strength, as the work is fixed to walls; but as doors and shutters are swung to and fro continually, and subject to jars and strains, their stiles and rails, upright and cross-framing members, as well as the panelling that fills them, require well-seasoned timber and the most accurate workmanship: without these conditions the joints open, the panels shrink from the grooves in which the edges are held, and split, while the frame itself, if of unseasoned material, 'buckles' or twists, so that the door or shutter will no longer shut flat in its frame.
Panelling and fireplaces are, however, opportunities for the display of carving, inlaying, and gilding. The reader has seen carved room panelling, probably, in many old houses. In some of the municipal 'palaces' in Flanders, e.g. in Bruges, and in the old rooms of the Louvre in Paris, carved panelling of the utmost grace and perfection, some of it in groups of life-sized portrait figures, may be studied by the tourist.
