Chapter II: Dissolve together

Dextrine 50
Water 50

Unite the two solutions thus formed; pass them through a cloth, so as to fall into a flat mould. When dry, use by dissolving in hot water.

AMERICAN GLAZE FOR POSTAGE-STAMPS:--

Dextrine 2
Vinegar 1
Water 5
Alcohol 1

Stamps are, however, very often surreptitiously removed by means of moisture. The following recipe renders this difficult. It consists of two preparations, one of which is applied to the stamp and one to the letter. It is particularly needed in America, where, according to a statement in a newspaper, _nearly one-third_ of all the postage-stamps are removed from letters, cleaned, and used over again.

I. _For the Letter._

Chromic acid 2.5 gr.
Caustic potash 15.0 ”
Water 15.0 ”
Sulphuric acid 0.5 ”
Sulphuric copper-oxide of ammonia 30.0 ”
Fine paper 4.0 ”

II. _On the Stamp._

Sturgeon’s bladder in water 7.0 gr.
Vinegar 1.0 ”

The chromic acid forms with the glue a substance insoluble in water, which causes the stamp not to yield to moisture. The two should be kept in two cups, and the letter first smeared with one and the stamp with the other. I have read of a physician who, finding that his postage-stamps were often stolen, adopted the precaution of giving their backs an application of croton-oil, or some similar powerful “anti-thief-matic,” the result of which was great temporary illness in his landlady and her family. For this recipe the reader must apply to a chemist!

EDER’S GUM FOR PHOTOGRAPHS.--Dissolve oxyhydrate of ammonia in vinous acid, to one part of which add twenty of starch-paste.

CEMENT FOR LEATHER OR PAPER IN BINDING BOOKS, &C.--Take 1 kilogramme of wheat-flour, and make it to a paste with 20 grammes of finely powdered alum. Boil this till a spoon will stand uptight in it. Cover the cardboard or cover with this, lay the leather or muslin upon it, and then with a roller press one upon the other. Leather should first be damped. Care must be taken that the paste be not too moist; secondly, that it is laid on very evenly and thinly.

Engravings or texts which have had a piece torn out can be restored as follows:--

Obtain a photograph from a perfect copy on corresponding paper, then with gum set it in, so as to supply the deficiency.

As the ravages of the _Book-worm_ form an important item in mending books, and as there is always some interest for collectors regarding this much talked of and rarely seen insect, I take the liberty of reproducing from the American _Science_ of March 24, 1893, an article on the subject. An appropriate motto for it might be:--

“Come hither, boy; we’ll hunt to-day
The book-worm, ravening beast of prey.”

THE RAVAGES OF BOOK-WORMS

At a meeting of the Massachusetts Historical Society, held February 9, 1893, Dr. Samuel A. Green, after showing two volumes that had been completely riddled by the ravages of insects, as well as some specimens of the animals in various stages, made the following remarks:--

* * * * *

For a long period of years I have been looking for living specimens of the so-called “book-worm,” of which traces are occasionally found in old volumes; and I was expecting to find an invertebrate animal of the class of annelids. In this library at the present time there are books perforated with clean-cut holes opening into sinuous cavities, which usually run up the back of the volumes, and sometimes perforate the leather covers and the body of the book; but I have never detected the live culprit that does the mischief. For the most part the injury is confined to such as are bound in leather, and the ravages of the insect appear to depend on its hunger. The external orifices look like so many shot-holes, but the channels are anything but straight. From a long examination of the subject I am inclined to think that all the damage was done before the library came to this site in the spring of 1833. At all events, there is no reason to suppose that any of the mischief has been caused during the last fifty years. Perhaps the furnace-heat dries up the moisture which is a requisite condition for the life and propagation of the little animal.

Nearly two years ago I received a parcel of books from Florida, of which some were infested with vermin, and more or less perforated in the manner I have described. It occurred to me that they would make a good breeding farm and experiment station for learning the habits of the insect; and I accordingly sent several of the volumes to my friend Mr. Samuel Garman, who is connected with the Museum of Comparative Zoology at Cambridge, for his care and observation. From him I learn that the principal offender is an animal known popularly as the Buffalo Bug, though he is helped in his work by kindred spirits, not allied to him according to the rules of natural history. Mr. Garman’s letter gives the result of his labours so fully as to leave nothing to be desired, and is as follows:--

“MUSEUM OF COMPARATIVE ZOOLOGY, CAMBRIDGE, MASS., _February 7, 1893_.

“DR. SAMUEL A. GREEN, BOSTON, MASS.

“SIR,--The infested books sent for examination to this Museum, through the kindness of Mr. George E. Littlefield, were received July 15, 1891. They were inspected, and, containing individuals of a couple of species of living insects, were at once enclosed in glass for further developments. A year afterward live specimens of both kinds were still at work. Besides those that reached us alive, a third species had left traces of former presence in a number of empty egg-cases.

“Five of the volumes were bound in cloth. On these the principal damage appeared at the edges, which were eaten away and disfigured by large burrows extending inward. Two volumes were bound in leather. The edges of these were not so much disturbed; but numerous perforations, somewhat like shot-holes externally, passed through the leather, enlarging and ramifying in the interior. As if made by smaller insects, the sides of these holes were neater and cleaner cuttings than those in the burrows on the edges of the other volumes.

“The insects were all identified as well known enemies of libraries, cabinets, and wardrobes. One of them is a species of what are commonly designated ‘fish bugs,’ ‘silver fish,’ ‘bristle tails,’ &c. By entomologists they are called _Lepisma_; the species in hand is probably _Lepisma saccharina_. It is a small, elongate, silvery, very active creature, frequently discovered under objects, or between the leaves of books, whence it escapes by its extraordinary quickness of movement. Paste and the sizing or enamel of some kinds of paper are very attractive to it. In some cases it eats off the entire surface of the sheet, including the ink, without making perforations; in others the leaves are completely destroyed. The last specimen of this insect in these books was killed February 5, 1893, which proves the species to be sufficiently at home in this latitude.

“The second of the three is one of the ‘Buffalo Bugs.’ or ‘Carpet Bugs,’ so called; not really bugs, but beetles. The species before us is the _Anthrenus varius_ of scientists, very common in Boston and Cambridge, as in other portions of the temperate regions and the tropics. Very likely the ‘shot-holes’ in the leather-bound volumes are of its making, though it may have been aided in the deeper and larger chambers by one or both of the others. The damage done by this insect in the house, museum, and library is too well known to call for further comment. Living individuals were taken from the books nearly a year after they were isolated.

“The third species had disappeared before the arrival of the books, leaving only its burrows, excrement, and empty egg-cases, which, however, leave no doubt of the identity of the animal with one of the cockroaches, possibly the species _Blatta Australasiæ_. The cases agree in size with those of _Blatta Americana_, but have thirteen impressions on each side, as if the number of eggs were twenty-six. The ravages of the cockroaches are greatest in the tropics, but some of the species range through the temperate zones and even northward. An extract from Westwood and Drury will serve to indicate the character of their work:--

“‘They devour all kinds of victuals, dressed and undressed, and damage all sorts of clothing, leather, books, paper, &c., which, if they do not destroy, at least they soil, as they frequently deposit a drop of their excrement where they settle. They swarm by myriads in old houses, making every part filthy beyond description. They have also the power of making a noise like a sharp knocking with the knuckle upon the wainscotting, _Blatta gigantea_ being thence known to the West Indies by the name of drummer; and this they keep up, replying to each other, throughout the night. Moreover, they attack sleeping persons, and will even eat the extremities of the dead.’

“This quotation makes it appear that authors as well as books are endangered by this outlaw. With energies exclusively turned against properly selected examples of both, what a world of good it might do mankind! The discrimination lacking, the insect must be treated as a common enemy. As a bane for ‘silver fish’ and cockroaches, pyrethrum insect powder is said to be effectual. For a number of years I have used, on lepisma and roach, a mixture containing phosphorus, ‘The Infallible Water Bug and Roach Exterminator,’ made by Barnard & Co., 7 Temple Place, Boston, and, without other interest in advertising the compound, have found it entirely satisfactory in its effects. Bisulphide carbon, evaporated in closed boxes or cases containing the infested articles, is used to do away with the ‘Buffalo Bugs.’--Very respectfully yours,

“SAMUEL GARMAN.”

I can remember that many years ago there was to be seen in the bookshop of John Penington, Philadelphia, a book-worm preserved in spirits in a vial. The manner in which this species of teredo penetrates wood and leather as well as paper is not the least curious of its habits.

The great amount of injury inflicted by boring-insects in books, wood, and all weak substances is sufficient reason for giving so much space to this subject. From a ship to a manuscript, nothing is safe from them.

PAPIER-MÂCHÉ

REPAIRING TOYS--MAKING GROUNDS FOR PICTURES AND WALLS--CARTON-CUIR AND CARTON-PIERRE

Soft paper, when mixed with water, gum, or, better still, with flour-paste, forms a substance which can be moulded to any form, and which, when dry, will be as hard as cardboard. Its hardness and durability may be increased by mingling with it many substances.

Combined with soft leather in small fragments or with the dust of leather, it forms what the French call _carton-cuir_. In this, or even in its natural state--that is, paper and paste--_papier-mâché_, as it is termed, can under pressure be made as hard as any wood. I have seen all kinds of articles of furniture made from it. In America there are manufactories in which pails or buckets, tubs, firkins, and even durable boats, are thus manufactured. There is in Bergen, Norway, a church built entirely of it mixed with lime. For certain kinds of mending it is very valuable.

Though not so plastic as clay, _papier-mâché_ can, with a little practice, be moulded into any form. It consists simply of pasting piece on to piece, pressing it meantime as much as possible with the fingers or a wooden implement like a pestle. The pressure should be applied as it gradually dries. Any one can thus make very hard cardboard with a bread-roller on a board.

If you have the cardboard cover of a book badly damaged, with even a portion gone, it can be restored by using _papier-mâché_ in which a solution of glue or gum has been infused. Glue it specially at the edges. For such repairing take paper-dust or pulp, combined with gum-arabic in alum-water solution, or simply the gum. This is easily moulded and smoothed into any cracks or torn places.

If _parchment_ be torn away it is easily replaced. Cut a piece to replace the missing portion, dampen it and the edge which it is to join till quite soft, then glue the two together, using pressure. I have just effected this myself with a cover of which half was gone, and the mending is hardly visible. Use the broad knife freely to press down the edges.

By combination with a mixture of nitric or sulphuric acid and water, _soft_ paper becomes parchment-like and very hard. This requires careful experimenting, for its success depends on the quality of the acid and the texture of the paper. Very remarkable results have been obtained from this, such as material resembling ivory, horn, and tortoise-shell, in large blocks.

Waste-paper is so common and cheap that _papier-mâché_ can always be made anywhere. It is well adapted to close cracks in wood, walls, or elsewhere; and for those who wish for an employment or amusement, it affords endless facilities. One of these is the mending or making of toys.

A common mask is made as follows. On a face carved in wood and oiled there is spread common coarse soft paper wetted, which is carefully pressed down, and more paper and paste added, till it is of the requisite thickness. It is then, when rather dry, taken off and left to dry perfectly. It is then painted and varnished. Should a mask be broken, wet it, paste glue-paper over it, and paint it again.

_Papier-mâché_ is popularly synonymous with that which is trashy and sham in art, simply because its capacities and applications are not known. Thus leather-work was long despised as only affording imitations of carved wood. But in the hands of a true artist--that is, of an _original designer_, who applies, and not a mere artisan, who imitates or copies--_papier-mâché_ is as much a subject for art as any other material. It can be used in many ways, more or less allied to mending, as are all arts. Thus paper in fine powder, or reduced to a fine paste--or pulp--can be, with a little practice, mixed with gum and _painted_ with a brush on a surface so as to produce relief. A very little elevation or depression thus serves to produce grounds which may serve to give light or shadow to pictures. Thus pastel painting or crayon in colours rubbed in, which has always been, even in the most vigorous hands, a weak or “softly sweet” art, may be made very vigorous by firmly relieving and roughening the ground; for, as the great American painter, ALLSTON, often strengthened his colours by mixing sand with them, so pastel painting which lacks “sand” can have it supplied by mixing it with the gum for the ground.

To understand this process more clearly, let it be observed that, as the illuminators of mediæval manuscripts gave relief and the appearance of solidity to gold by making a raised surface with a powder of _gesso_ (plaster of Paris) and clay and gum, so this principle can be carried out to a far greater extent by giving relief to a ground. Here those of limited views, who never get beyond the merely artisan stage of art, will at once decry this as shamming, and as imitating effect by the aid of modelling, and not being true art, quite forgetting that all is true to genius, and everything more or less sham in the mere imitation.

Having a surface, either panel or Bristol board, which latter had better be pasted to a panel or good thick solid cardboard, begin by taking a little gum or glue in tolerably fluid solution on the point of a brush, and incorporating with it the paper pulp or cloth-dust to a very soft paste, with which paint what is to be in relief. The same effect is produced in oil by using a heavier, thicker kind of paint. That is all the difference, one being as legitimate as the other. By intermixing chalk or sand or clay, and by using glass-paper where the crayon, &c., refuse to take easily, the relief adapts itself to every substance. In this, as in every process known, the artist must at first experiment a little, according to his materials.

Solid sheets of fine hard paper, with strong paste between, when passed between rollers form a kind of _papier-mâché_ which, is as hard as wood, fire-proof, and, what is most singular, more durable than iron. Wheels for railway carriages are often made of it, and they never warp under the action of heat or cold, neither do they crack nor bend. You can make this cardboard for yourself of very good quality by this process:--Take a sheet of writing-paper--the better the quality the better the result will be--cover it with good flour-paste in which there is a little alum and glue and a few drops of oil of cloves, which latter will prevent paste from turning or souring. Then lay on this another sheet, apply another coat of paste, and when it is a little dry or past the softer stage, yet while still capable of adhesion, lay the sheets on a hard, smooth slab or table, and pass a roller over them, at first gently, but eventually frequently, and with force. Add as many sheets as necessary for the thickness required. It will be understood that if the surface on which this sheet is formed were an intaglio-cut die or mould, the cardboard when taken up would present a bas-relief of it as hard as any wood, and the whole would form a panel which could be used for the side of a box or to be set in a cabinet. If made of good paper and firmly rolled, this panel will be in every respect equal to wood for all decorative purposes.

As anybody who can carve wood at all can cut moulds, and as a wooden mould, if kept well oiled (or otherwise secured from yielding to moisture), will serve for _papier-mâché_ and leather or wood-paste casting, it is remarkable that such work is so very little practised by the students of the minor arts. That such panels can be very easily and rapidly made I know by experience; that the materials for the work are cheap speaks for itself; and, finally, that beautiful panels for cabinets and doors, whether made of carved wood, stamped leather, or _papier-mâché_ bring a very good price will also be most apparent to anybody who will go to a fashionable cabinetmaker and order them. Thus we will say that a small plain cabinet costs £5. Put into it six panels, really costing about 6d. each to mould, and the price will be £10. Such pressed panels are admirably adapted for binding books, as, when properly made and dried, they cannot warp or bend. If covered with relief they may be made very beautiful. Simply blackened or browned, then rubbed with oil, varnished with SOEHNÉE, No. 3, and rubbed by hand, they are as beautiful as polished wood or leather.

_Papier-mâché_, pulp, or paper powder can be combined with caoutchouc or indiarubber, which latter can be itself dissolved in benzine, camphine, sulphuric ether, and other solvent mediums, so as to form a paste which becomes like indiarubber when dry or as it hardens. Mixed with sulphur this forms vulcanite. Or it may be combined with white colouring matter of almost any kind. This can be applied to mending the broken noses of dolls, or any other wounds which these pretty semblances of humanity often receive, their beauty being unfortunately generally more shortlived than that of their prototypes. The final finish of such reparation is a coat of paint. In many cases this is better when rubbed on with the finger than when directly painted. The reader who shall have studied this work will find no difficulty in restoring any toy.

I may, however, here remark that “no solution of india rubber can be well moulded without intimate intermixture of sulphur, aided by heat and pressure. This is a difficult process, and the amateur would do well, therefore, to purchase rubber composition, which he may do at any large shop in which rubber goods are made as a specialty” (_Work_, May 21, 1892).

It is easy to make any article of _papier-mâché_ if the mere beginning of a form has once been shaped; because, after that is set, all that we have to do is to gradually paste one piece of paper on, here and there, till it is finished. This beginning is very easy if we have an object on which to begin. Thus take a vase or cup. Oil this, and then lay on and all around it soft, damp paper. Newspaper will do--a _soft_, white printing paper. Then, with a broad brush, lay on paste, and apply a second coat of paper. Press it meanwhile as hard as you can. Continue this till the _papier-mâché_ is thick enough. When dry, take a penknife and cut a line through from top to bottom. Scale it off, and reunite the edges with strong glue; then paste over the line of junction a strip of paper. Then you will have a cup.

If it be rough, cut it smooth and use glass-paper. When finished it may be painted or covered with wet leather, which can be worked into relief. Or it may be made to look like ivory by the process elsewhere described. Paper may in this process be combined with soft leather rags; as, for instance, pieces of old gloves out of which the thread has been taken, old chamois, bookbinders’ clippings, or the like. This forms effectively leather.

CARTON-PIERRE, or stone-paper, is a very useful composition, which is very fully described by GEORGE PARLAND in _Work_, July 2, 1893. It consists of paper scraps, in the proportion of an ordinary washing boiler or copper one-half full of boiling water and about one-half paper waste. Add two pounds of best flour-paste; also, in a separate vessel, a quart of water, into which sprinkle a handful of fine plaster of Paris. Let it stand ten minutes before mixing it. “When the paper in the copper has become a fine pulp add the flour-paste, keeping the whole well stirred. Fifteen minutes after add the plaster, and a few minutes later rake out the fire from under the boiler. Have ready three pails of fine ground whiting; pour in one pail of whiting and stir up well, adding more whiting till the stick used to stir will stand of itself in the mixture. Let it cool, and it will be ready for use.

“Some firms,” writes Mr. PARLAND, “add powdered alum in the boiling process, others add one pint of boiled linseed-oil; but if made according to the previous directions, an excellent _carton-pierre_ will result, which gives very fine impressions from moulds. If it be cast in a plaster mould, the latter should have two or three coats of shellac varnish, and then be well oiled.... In using the _carton_, sprinkle some fine plaster of Paris on a bench, and taking a lump of the newly made _carton_, mix it well with dry plaster, adding more plaster, as bakers would add flour to their dough. Having worked it well in this way until it will not stick to the fingers, with clean hands roll pieces very smooth in the palms, or on a smooth level board, and press each roll into the cavities and hollows of the mould, _often wetting the edges of the carton_ in the mould before adding a fresh piece to it. The casts must not be more than from an eighth to a quarter of an inch in thickness, except at the outside edges of the mould.... The casts must stand about twenty-four hours, and then be baked in not more than 100° heat.”

The reader who is specially interested in _papier-mâché_ will find a series of articles on the subject in _Work_, Nos. 3, 6, 12, 17, 22, 25.

Pipeclay, to which calcined magnesia, whiting, or baryta may be added or omitted according to the body required, may be combined with _papier-mâché_ and gluten, such as gum-arabic or dextrine or flour-paste, which will form under pressure, or even by hand-rolling, a very hard and finely grained substance, which is specially adapted to painting pictures. Plates or _tavole_ are sold very cheaply in Florence of _papier-mâché_, which are as hard, heavy, and glossy as ebony. It is not generally realised that an expensive hydraulic-press or steam-engine is not needed by the amateur to harden _papier-mâché_. A common bread-roller, passed many times over the material, will work it “down and in,” quite as well as direct pressure, and very often much better.

_Papier-mâché_ mixed and macerated with indiarubber or gutta-percha and benzole (_vide_ Indiarubber) forms in many cases a very good substitute for leather. It can also be combined with _flexible_ varnish to make leather. Very valuable soles can be made, or broken ones repaired, by taking card or pasteboard and soaking it in a hot solution of indiarubber. These waterproofed soles, whether of cardboard or leather, are easily prepared, as easily applied and renewed, and they will keep the true sole from wearing out forever, if renewed.

Singular as it seems, there are not many persons who are familiar with the properties or texture of so familiar a substance as paper. We know that if wetted it grows soft, but still remains, as it were, knotty, and that when chewed it does not properly dissolve. Yet if the reader will take a piece of thoroughly wetted paper, and knead or macerate it with a knife for some time with gum in solution, he will find it gradually becomes a soft paste, as flexible and as capable of moulding as putty or clay. This is not the same as _papier-mâché_, which consists of paper merely wet or mixed and boiled with paste, and contains fibre and knottiness. The finely macerated paper, combined with an adhesive, is ductile, impressionable, sets well, and readily receives pressure on rolling, under which it becomes extremely hard. Paper thus _completely softened_ is readily made into sheets, and may be easily applied not only to fill up worm-holes in leaves and completely torn-away corners, &c., but is very useful for cracks and cavities in wood and other substances. It may be made up with any gums, such as gum-arabic, dextrine, fish-glue, and also with caseine, gutta-percha, varnish, and most of the substances used in cements. Paper when thus softened and mixed with, _e.g._, fine glue and glycerine, or with flour-paste, can be moulded and applied in ornamental forms to any surface.

There is this great difference between simply _wet_ paper, however wet it may be, and that which is completely softened by maceration. The former is always lumpy, the latter passes under the blade of a knife like soft clay or putty. When made up with gum, glue, and glycerine, or strong paste, it is, when dry, like light wood, but less brittle. Kneaded with Indiarubber solution and glue, it becomes like leather, and can be used in several varieties of repairs. Rolled into sheets, this composition makes very good and cheap artificial leather for hangings. To manufacture these, spread the composition with a broad brush or dabber on a slate or marble table, and when rather dry pass over it a wooden roller. Some practice is needed not to roll it when too soft. If intaglio patterns are cut in the roller, the sheets will give them in relief. It is worth noting here that a great many pieces of old hangings sold as leather are really only made of _papier-mâché_, or _carton-cuir_, and glue. These hangings, whether of leather or counterfeited, can be often bought in a damaged condition very cheaply, and can be easily restored with this composition, to great profit. When mixed with white lead, or oil paint and glue, soft paper becomes harder and firmer, and under pressure is as hard and heavy as any wood. White paper with holly wood or white larch or lime-tree wood in powder, and white gelatine--better if bone or ivory dust be added, with a little Naples yellow (oil)--forms a beautiful cement.

It will be seen by what I have written that cavities, holes, cracks, and defects in most substances, including wood and leather, can be perfectly remedied with paper in combination with glue, gum, or other substances; and as it is always to be obtained, a knowledge of its nature and applications cannot fail to be of value to all menders and restorers.

_Papier-mâché_, like all substantial or putty-like cements, involves moulding or casting. This subject is exhaustively treated in the _Vollständige Anleitung zum Formen und Giessen_, by Eduard Uhlenhuth; Vienna, A. Hartleben, price 3s. On the subject of paper consult the _Handbuch der praktischen Papier-Fabrikation_, by Dr. Stanislaus Mierzinski, three volumes, which is not only the latest, but by far the most comprehensive, work on the subject with which I am acquainted. And here I may observe in this connection that if my references have been chiefly to German works, it is because, in the minor technical applications of chemistry to the arts, and in preparing intelligible practical treatises on such subjects, the Germans have been, especially of late, by far the first nation in Europe.

I may mention that since writing the foregoing passages I purchased, for a mere trifle, in Florence two carved heads of the fourteenth century in walnut wood. They had suffered very much from time and wanton abuse, their noses having been hacked off. I made a mixture of soft paper-paste and gum-arabic, working the two thoroughly in together with a knife-blade till the composition was as soft as butter. This thorough maceration is essential to produce a durable body. With this I filled up the holes, made new noses, and painted the whole with Vandyke brown, or brown-black. In a few minutes the restoration was complete, and the heads which had cost one franc each are now worth at least thirty francs. I should say that the portions restored are as hard as the original wood.

It is not always an easy matter to reduce paper to a perfectly soft paste, such as is called in French _papier-pourri_. A small quantity can be mashed with a knife-blade and flour-paste or gum. A large quantity is prepared as follows:--

Take clippings of paper and leave them a long time in water, which must be occasionally changed. When quite dissolved or soft, bray the paper in a mortar, and finally boil in very hot water. To give it consistency, add flour-paste or gum. This makes a very fine cement, which will receive the most delicate impression. It is invaluable for all kinds of dry mending.

As I have shown, it can be applied to make or mend defective leaves of books, to fill up worm-holes in leaves, to repair drawings and pictures on wood or canvas, and when mixed with any gum which sets hard, to restore, add to, fill, or imitate woodwork. Under pressure and combined with different powders it becomes as hard as ebony and fire-proof. Its extraordinary value and general utility are as yet very far from being much known.

MENDING STONE-WORK

MOSAICS--CERESA-WORK--PORCELAIN OR CROCKERY MOSAIC

Mending or repairing _stone_, involving its imitations, is a widely extended branch of technical science, and one which has of late years called forth much invention. The most widely spread and ancient means of uniting and repairing this material is mortar, or the mixture of burned and then slacked lime with water. Lime is made most commonly from limestone or marble. It improves in quality when carbonate of lime in organic formation, such as sea-shells, is used; and there are degrees of excellence in these, from common oyster-shells to others of a finer kind, such as those with which the brilliantly white and hard _chunam_ of India is made. In certain places mortar, when well made, becomes with age as hard as flint. In American towns, where anthracite coal is burned, it rots away in chimneys under the influence of sulphurous acid with great rapidity. In the Pacific Islands, where lime is made from delicate small sea-shells or coral, and mortar is like a paint or enamel, a missionary has recorded that, when he taught the natives how to make it, they whitewashed everything, even to the children, who thus became white people.

The misapplied word _mastic_, which suggests a gum, refers to certain modifications of mortar into which _oil_ enters; also the oxides of lead or zinc. “Oil forms with these an insoluble soap, which includes or binds the other materials, forming, after one month’s drying, a very hard substance,” which some say is as hard as stone, but which depends entirely on the quality and combination; for I have seen so-called _mastic_ applied to coating cheaply built houses, which cracked or crumbled away like mere plaster of Paris.

To thoroughly amalgamate mastics, it is usual to put their ingredients into casks which are two-thirds filled, and then revolved by machinery. The oil is then added. At least two days are required for the process. The following recipes for mastics are among the best, having been approved by LEHNER. It may here be remarked, once for all, not only as regards mastics, but all recipes in this work, that unless the materials indicated are of the very best quality, and the processes be most thoroughly carried out, the experimenter cannot expect complete success. More than this, the experimenter must not be satisfied with a single trial. If every recipe could be at once executed by every cook, we should find the most exquisite cookery on every table in Europe. I once published the correct recipe for making objects of a peculiar kind of _papier-mâché_ hardened. It was very easy to make. I had seen specimens of the ware, and I received the recipe from the inventor. Moreover, a great deal of money had been made by it. However, soon after I had published it I received an indignant letter from the head of a large manufacturing house, stating that they had tried my recipe and utterly failed!

FRENCH MASTIC:--

Quartz or flint sand, parts 300
Powdered quicklime, ” 100
Litharge, ” 50
Linseed-oil, ” 35

PAGET’S MASTIC:--

Flint sand 315
Washed chalk 105
White lead 25
Minium 10
Sugar of lead in solution 45
Linseed-oil 35

The paste or “dough” thus formed should be ground with horizontal rollers in a mill, such as is used for chocolate, until all the ingredients are _very_ thoroughly amalgamated.

A VERY GOOD CEMENT FOR MENDING, especially where the objects are exposed to water, whether they be of stone or earthenware, is made as follows:--

Powdered glass 40
Washed litharge 40
Linseed-oil varnish 20

The powdered glass is prepared by heating glass red-hot, casting it into water, grinding and sifting it. This powder is saturated with the linseed-oil varnish, and heated in a kettle. This cement sets hard in three days. LEHNER observes that glass-powder serves in such recipes to resist the action of acids, &c., since it forms in combination on the surface a glaze of great hardness; that is, the glass and lead form a chemical combination. Pulverised calcined glass therefore acts not as an “indifferent” but as a chemical ingredient.

CASEINE, or Cheese, forms the basis of several recipes for mending stone, as when there are holes in a block or the mortar has given way. To prepare it for use (LEHNER), we let milk stand in a cool place, skimming away with the utmost care all the cream. Place this on a filter, and pour on it rain-water till it is purified from every trace of lactic acid; then tie it in a cloth, boil it in water, and spread it on blotting-paper in a warm place, when it will be a horn-like substance. This will keep for a long time. To prepare it for use, rub it in a saucer with water.

TO MEND STONE make the following:--

Caseine 12
Slacked lime 50
Fine sand 50

Another recipe:--

Boil new cheese in water till it draws out in threads, stirring in slacked lime and sifted wood-ashes in the following proportions:--

Cheese 100
Water 200
Slacked lime 25
Wood-ashes 20

This may also be used to close cavities in trees or in wood.

A CHEESE CEMENT FOR STONE, and for many other purposes, is made as follows. It may be kept for a long time, and is very durable (LEHNER):--

Caseine 200
Calcined lime 40
Camphor 1

This must be closely incorporated and kept well corked. When it is to be used mix it with water, and apply at once.

The following cement was used by the Romans especially in setting mosaics. It becomes as hard as marble, and sets with great rapidity:--To one quart of milk add the white of five eggs, and stir in powdered quicklime till a paste is formed. This composition may be used to repair or make _scagliola_, which is fragments of marble or stone embedded in a hard mass. When it sets, polish the surface with rasps, and rub down with a rough stone, and finally polish with marble dust, and then emery or tripoli. Beautiful slabs for tables, columns, floors, and walls can thus be made. It is valuable for repairing.

CERESA is allied to this. We make a basis of this or any other cement which will _hold firmly_, and press into the surface powdered glass, which may be fine or of any degree of coarseness. Coarse grains shine most brilliantly; fine powder is best adapted to delicate shading. The effect is best when mosaic stones and gold cubes are sparingly introduced. To make the gold cubes, take two small panes of window glass, cover one side of each with varnish or mastic cement, lay between them gold-leaf, and join them. Very beautiful pictures can be made in this manner. Nor is it at all necessary that they should be finely executed for ordinary decoration. All that is needed for this beautiful and little-known art is the cement, a quantity of glass or stone of different colours, and a mortar and pestle. The mosaic cubes, with those of gold, can be bought in London.

Allied to this is an art which I believe I can claim to have invented. It consists of breaking waste chinaware, crockery, or fictile ware into small squares or triangles, and setting them as mosaic in cement. The advantage of it is the cheapness of the material, and the infinite number of shades of colour which can be selected for it. Its disadvantage is, that it will not wear as a pavement, but it is perfectly adapted to walls.

A STRONG, COARSE CEMENT FOR BRICK OR STONE WORK in building is made as follows:--

Slacked lime 40
Brick-dust 10
Iron filings 10
Ox-blood 8
Water 8

The blood is stirred as it comes from the slaughtered beast with a broom for ten minutes to break the fibre. It should then be mixed with the water and kneaded with the powder. Glue may be substituted for the blood. This cement, if properly made, sets very hard and adhesively.

FOR TILES, BRICKS, OR COMPOSITION:--

Slacked lime 100
Sifted stone-coal ashes 50
Stirred ox-blood 15

It may be observed that many of the cheaper cements can be employed to form large bricks by combination with broken stone or rubble, gravel, pebbles, brickbats, &c. Another method, called CONCRETE, is to make cases of boards, and to form a solid wall by pouring in the mixture, or ramming it down, according to its hardness. Thus a house is made entirely in one piece; but its excellence depends entirely on the quality of the cement employed, and on the care taken in building. Simple lime mortar, if not of a superior quality, hastily formed, as I have seen, is very apt to crack and break off. Where hydraulic cement is cheap and good, houses can be built as firm as granite. A good and strong cement of this kind can be made as follows:--

Burned lime 10
Caseine 12
Hydraulic cement 30

The proportions may be very much varied in such cements according to their price, but generally with a satisfactory result.

Fractures or discolorations in marble, as in statuary, are so perfectly repaired in Florence that the juncture is not perceptible. Even dark spots are drilled out. The process is to drill a round concave hole, and cut the piece to be inserted so as to exactly fit as a convex plug. It is then fastened in with transparent mastic or other clear cement. It will be seen, on due consideration, that this is extremely ingenious, because by it alone can a perfectly tight fit be secured. By turning the plug in the hollow it speedily grinds itself into an accurate plug; so when the cement is applied it can be reduced to a minimum--in fact, by this means the line of junction is reduced to its finest limit.

Where a very strong cement is needed for stone-work, it can be prepared by mixing a fine cement powder--_e.g._, Portland cement--with liquid silicate of soda. As it dries almost at once, it must be promptly applied. It is particularly well adapted for building under water, since it then becomes extremely hard. Before applying it smear the stone with pure silicate.

The following is highly commended by LEHNER:--

Mending statues of gypsum or plaster of Paris is allied to stone-work. The broken edges are washed with water till no more is absorbed and the surface remains wet. Then stir fresh calcined white plaster of Paris with much water to a thin paste, and continue to stir this till it is cold. Then rapidly paint this paste on the broken edges, continuing to press the two together till they set hard.

It is, says LEHNER, a peculiarity of gypsum that when mixed with _alum_ dissolved in water it takes a much longer time to harden, but is very much harder in the end. Thus, if we let the powdered gypsum lie for twenty-four hours in alum-water, dry it, and then calcine it again, the powder when mixed with water sets to a stone as hard as marble.

Plaster of Paris and alum, combined with the fine powder of calcined glass, form a very hard and durable cement, of very general utility in all mending of stone-work.

For an exhaustive work on the subject of not only mending stone-work, but also of making artificial stone and many cements, as well as combining and adapting to use paper, cellulose, sawdust and shavings, gypsum, chalk, glue, &c., including not only ancient but also the most recent recipes, consult _Die Fabrikation künstlicher plastischer Massen_, by Johannes Hofer; Leipzig, A. Hartleben, price 4s.

REPAIRING IVORY

Works of art in carved ivory or bone are very valuable when perfect, yet when broken or defective they may very often be purchased for a trifle. Yet the process of mending them or restoring the missing portions is not difficult.

The first thing to consider is the colour. When old ivory has only acquired a delicate hue, as of Naples yellow, this adds to its attractiveness; nor are the brownish shadows and marks which gather in the angles of the reliefs repulsive. These may be left untouched, and even imitated. But a great deal of old ivory becomes of blackish bistre, or of a dirty, spotted brown or neutral tint, which has nothing in common with artistic effect, and suggests, like old slums in cities, more that is repulsive than picturesque. To clean such pieces, dissolve rock-alum in rain-water till it is white or forms a full saturation. Boil this, and keep the ivory in the boiling solution for about an hour, taking it out from time to time and cleaning it with a soft brush. Then let it dry in a damp linen or muslin rag; it will then be cleaned.

Ivory is often bleached by the simple process of damping, or wiping it with water and then exposing it to the rays of the sun; which must, however, be frequently repeated. According to LEHNER, the only perfect and certain process by which any ivory can be cleaned is to steep the article for some time in ether or benzole, in order to extract any fatty matter, then to wash it in water, and finally keep it in super-oxide of hydrogen (_Wasserstoff, super-oxide_) till it is bleached, after which wash again in water.

TO SUPPLY MISSING PORTIONS.--Take ivory-dust, such as can be bought of every ivory-turner, sift it to an impalpable powder, or else levigate or grind it down under water as fine as flour in a mortar. Then combine this with gum arabic, in alum solution, or the silicate of potash. Egg-shells, levigated, may be substituted for the ivory-dust, and are even less likely to turn grey; and very fine white glue or gelatine of the clearest kind may be substituted for the gum-arabic.

LOUIS EDGAR ANDÉS, in his able work on Ivory, Horn, Mother-of-Pearl, and Tortoise-shell, explains a process much like that already described. According to him, take finely powdered bone (or ivory-dust), combine it with white of eggs, and the result will be an intensely hard substance, which can be turned or carved like ivory. To perfect this the mass should be subjected to a heat of from 50° to 60° centigrade, and then to strong pressure. Gelatine or best glue, with glycerine, is quite as good as the white of eggs, and it may to advantage be combined with the latter. Having very thoroughly mixed the composition, take the broken ivory article, repair the missing portions, and fill the cavities with the paste. Though not equal to celluloid as an imitation of new and fresh ivory, this cement is very much like old bone and ivory, and _after a little experimenting_ the artistic amateur may succeed in so blending the _binder_ or adhesive with the dust as to take casts which are almost perfect imitations of the originals. But let it be observed in this, as in everything, one must not expect perfect success at a first trial, as too many do.

When the paste is dry, smooth the surface with a sharp cutter, so as to remove any small projections, and then polish it, first with fine emery or tripoli, then with a burnisher, finally by hand.

If you have, for example, an old flat plate of ivory, like one of the fourteenth century now before me, which I bought for a mere trifle because it was broken, lay it in an exactly fitting box--a strip of tin in a square will answer--and fill in the vacancy. The missing ornament on the upper side can be carved, or even supplied from a hardened stamp or mould of rolled soft bread-crumb. This bread-crumb can be made very hard by admixture with a very little nitric acid and water. Imitation meerschaum pipes, which are rather like ivory or bone, are made from this composition by pressure.

I may here mention that this ivory or bone cement, which is little known, is admirably adapted to repair broken inlaying. There was in Florence, in the sixteenth century, an extensive manufacture of delicate bas-reliefs for small caskets from _lime and rice_, which greatly resembled bone or ivory. It was extremely durable, probably from being extremely well worked. Specimens of it bring a high price.

A very slight infusion of Naples yellow, to which a suspicion of brown, reduced in Chinese white, has been added, gives to the paste an old-ivory colour. The corners and outlines may be shaded in Vandyke brown.

Before attempting to glue or mastic fractured ivories, they should always be washed in the alum solution, else they will often refuse to adhere.

When there is a little addition of whiting and a little oil, very well worked into the ivory paste, and it is allowed to dry thoroughly, it may be cut or carved into any shape.

Ivory or bone when very old becomes brittle or crumbling and falls to powder, because certain organic substances dry out of it, leaving chiefly lime as their residue. When the ivories from Nineveh were brought to the British Museum the celebrated Sir Joseph Hooker suggested that they should be steeped in gelatine. This effected a perfect restoration. When a case occurs in which an ivory article, a bone, or skull is so fragile that it will not bear the slightest touch without falling to dust, it may often be saved by gently _spraying_ on it water in which gelatine or glue has been dissolved. As the glue may be made by boiling old gloves, and as a spray can be easily improvised, it will be seen that excavators and openers of ancient tombs might by this means save thousands of curious relics which are allowed to perish. As it is certainly a species of mending or of restoration, it is in place in this work. This is especially to be desired as to skulls of the earliest ages, which are of inestimable value, of which we have so very few, and of which thousands have perished which might have been preserved in the manner which I have indicated.

_Sprays_ for spreading perfume or medicated liquids, which can be adapted to thin liquid glue, may be had of all chemists. But we can effect the purpose better by taking a tooth-brush, or any brush of the kind, wetting, and then drawing it over a dull edge of a knife or a strip of tin. According to J. C. WIEGLEB, a Frenchman in his time received a very large pension for this invention, which was applied to spraying pastels. The Romans made a spray, very imperfectly, by suddenly squeezing or throwing liquids from a sponge.

Ivory handles to knives and forks, when loose, can be best reset by first pouring in a little strong vinegar. When dry use acidulated glue. A common recipe for this purpose is the following:--

Resin (colophonium) 20 parts
Sulphur 5 ”
Iron filings 8 ”

Heat, and use while soft.

In repairing ivory it is often necessary to stain it of different colours. Most of the old works on recipes contain directions for this. In that of RIS PAQUOT they are given as follows:--

First prepare a mixture of copper filings, rock-alum, and Roman vitriol. Boil it, let it be for six days, then add a little rock-alum. The piece of ivory to be dyed is kept in this solution for half an-hour. _To dye Red._--Boil logwood chips or cochineal in water; when hot add lead dross (_cendre gravelée_) about 25 grammes, keep it in the fire till the colour has taken, then add rock-alum. This is strained through linen, and the ivory to be dyed is put into this liquor. _Green._--Take one quart of lye made from vine-ashes (_cendre de sarment_), 7 grammes of powdered verdigris, a handful of common salt, with a little alum. Boil it to one-half; as soon as it is taken from the fire place the ivory in it, and leave it till properly coloured. _Blue._--Dissolve indigo and potash in water, and then mix this with a quart of vine-ash lye. _Black._--Boil the ivory in the following composition:--Vinegar, 500 grammes; gall-nuts pulverised, 12 grammes; nut-shells, 12 grammes. Boil down to one-half. These are all very strong dyes, which may be used for other substances.

“Ivory can be softened and made almost plastic by soaking in phosphoric acid. When washed with water, pressed, and dried, it will regain its former consistency.” Ivory-dust thus treated can be really rendered plastic. The process requires care.

In the _Magia Naturalis_ of HILDEBRAND, a work of the sixteenth century, we are told that ivory can be imitated or repaired with a cement made of powdered egg-shells, gum-arabic in solution, and the white of eggs. Dry it in the sun.

Allied to ivory is Horn. Deer-horn was frequently used as a material whence to make a substance which was moulded into many forms. For this purpose the hardest part of the horns was selected and filed or powdered, and then boiled in strong potash lye. Thus it became a paste, which was promptly pressed into moulds. When dry the figures were carefully polished. Ox-horn can be treated in the same manner. When cracked, carved horns or powder-flasks can be mended with this paste; also with mastic and whiting. Horn in a soft state is easily coloured by mixing with it any dye.[3]

It has been recently complained in a leading review, in an article on sales of ancient works of art, that imitations of antique works of ivory are now carried to such perfection that even the learned in such matters have been deceived. This is perfectly true, and therefore it is the greater pity that such imitation, which is not necessarily very expensive, cannot be extended to our great museums, the wealthiest of which thus far seldom get beyond rough, plain plaster-casts to make duplicates of ivory-work. The artists in imitation seem to be entirely in the employ of the people who deliberately sell counterfeits for genuine relics of antiquity. But, as Martin Luther or some one once remarked in reference to adapting hymns to popular airs, “There was no reason why the devil should keep all the good tunes to himself,” so is there none why duplicates of thousands of exquisite works in ivory, bone, and horn should not be better known to the world. It is possible that, to the world at large, there is little _real_ interest in such works; but interest will come in time with familiarity.

_Apropos_ to ivory, or horn, there is a process of applying an imitation of them to any kind of surface, which is, when executed with skill, remarkably effective. It is chiefly executed in Vienna, where it is applied to leather, plaster of Paris, wood, and wall-paper. With variations, it is essentially as follows:--

Cover the ground with flexible varnish, then paint over this with light Naples yellow, graduated as nicely to some old ivory model as possible. It is best not to have it all too uniformly of one tone, since old work often has its shades. The object here need not be to ape or copy old work, but to catch what is beautiful in it. Then fill in the outlines of the pattern, and the dots and irregularities near it, or anywhere, with brown more or less dark. For this, study old ivory. Then varnish with SOEHNÉE, No. 3. A great deal depends on the quality of this second coat. Finally rub down very thoroughly with chamois and hand, and repeat the process more than once if you want it very much like ivory. Very extraordinary and perfect imitations of ivory, bone, worn and glossy parchment and brown leather, wood, marble--in short, of any kind of work of art which has been rubbed and worn smooth by hand during centuries, can be made by this process of ivorying with alternate layers of varnish, colour, varnish, and so on.

When there is no relief the paint itself can be worked with wheel and tracer, and then repainted and varnished. This is a very beautiful art, specially applicable to book-covers, and often useful in repairing old work. I would here repeat what I said, that the object of imitating effects in old works of art, or in other kinds of art--which is so staunchly repudiated by mere artisans who themselves are generally only imitators of the designs of others--is not to make counterfeits, but to take from age or art beautiful effects, however produced, and apply them to work. Those who are too conscientious to execute stencilling on a wall, or to use moulds for leather-work, would do well to first consider whether they _know enough_ to design a really good or admirable stencil, or an excellent mould, for it is in the genius which originates and executes, not in the mere means, tools, and materials employed, that art consists. Art does not depend in the least on either making skill difficult or in rendering its methods easy; it displays skill, but scorns the Chinese standard of mere industry. An artist like ALBERT DÜRER would never have prided himself on only using certain tools as being “artistic;” he would, however, have made designs which would have forced originality and art into a photograph. There are marvellous effects of corrugation in ancient walls, plays of light and shade and colour and polish in rock and strand and heaps of ashes, which LEONARDO DA VINCI knew how to catch and transfer to different subjects, and at which perhaps the artisans of his time sneered as “not artistic.”

Age, which gives a certain exquisite charm to wine and words of wisdom, has done the same to all material things, of which, indeed, it may be strangely said that wherever it does not destroy a charm it confers one, like moonlight, which renders nightly shadows more terrible or else more beautiful.

It is to be regretted that this principle, which is a very important one, is but little understood. The manufacturers of all decorative art work at present endeavour without exception to make everything staringly, cruelly brand new, or else a mere copy of old work. What they need is to draw, as REMBRANDT did, from age so much of its peculiar charm as is adaptable to modern work.

I have introduced these remarks because the mender and restorer of old ivories and bookbindings and pictures, if he regards his occupation as an art--which it really is--is peculiarly adapted to fully appreciate them. Restoring, like copying, leads to creating new work. I think that any person of ordinary intelligence can, with zeal and application, learn to mend anything as described in this work, and from such mending it is much easier to learn to make works of minor art. “Short the step from senator to _podestá_--shorter the step from _podestá_ to king.”

A great merit and peculiarity of ivory, as of horn, is that it is tough and elastic, as well as of a beautiful transparent or diaphanous quality. These characteristics have, with the exception of its graining or texture, been well imitated thus far only in _celluloid_, which is unfortunately too expensive for very general use, and, what is worse, too liable to destruction. I, however, confidently anticipate that ere long some substance will be discovered much superior to celluloid as a substitute, and probably much cheaper and less perishable. To _celluloid_ I may, however, add the sulphuretted preparations of caoutchouc and gutta-percha, known as vulcanite or ebonite. These are indeed hard, tough, and elastic to perfection, but very dark and opaque.

LEHNER, in his work _Die Imitationen_, observes that imitations of ivory must be varied to suit the colour and quality of originals. This requires a study, firstly, of the adhesive or glue which is to be used. This, when colourless, is known as French gelatine, and is very expensive. In lieu thereof the experimenter may take best white Salisbury glue or gum-arabic prepared with alum-water. Secondly, the body, which may be of carbonate of magnesia, carbonate of lime, such as powdered marble, sulphuretted lime, or powdered gypsum, chalk, starch, or flour, white oxide of tin, zinc, sulphate of barytes or Chinese white, white oxide of lead. In combining, _e.g._, magnesia with the glue, an addition of ten per cent. of glycerine gives elasticity and a horn-like clearness. To harden artificial ivory made with glue, the objects are dipped into strong solution of alum or tannin for about four minutes. The tannin is best made from gall-apples. Objects thus made have an antique ivory, yellowish hue. Red chrome alkali may be used in solution with water instead of tannin, but it gives a stronger yellow.

According to HYATT’S patent, artificial ivory is made by combining a syrup made of eight parts shellac and three parts of ammoniac with forty of the oxide of zinc. This is heated and subjected to pressure.

CELLULOID is the best material for making artificial ivory. It is made by the combination of cellulose or vegetable fibre in the form of cotton-wool treated with acid; that is to say, gun-cotton and camphor. It is sold in thin leaves, &c., which can be softened at from 100° to 125° centigrade, so as to be moulded to any form. By infusion of colouring matter, such as oxide of zinc, cinnabar, &c., celluloid is made to resemble ivory, coral, or tortoise-shell. It has often been applied to making a perfect imitation of Florentine mosaic, and of course serves admirably to repair such work when broken.

A very strong cement for ivory, bone, or fine wood is made by boiling transparent gelatine in water to a thick mass. Add to this gum-mastic dissolved in alcohol, this solution being one-fourth, and stir into it pure white oxide of zinc till it forms a fluid like honey. This is also of itself an artificial ivory, when prepared and dried in the mass. Another can be made by combining diamond cement (_vide_ Glass) with powdered ivory and a little glycerine. Also with the same, or very strong white glue and powdered egg-shells, which latter should have been boiled. Also white of egg, gum-arabic, a very little strong vinegar, and levigated egg-shells.

Another recipe for such mending or making of ivory and similar substances is to take soft and very white paper in pulp, combined with cotton-wool, treated with very dilute acid or _strong_ vinegar. To this add powdered egg-shells, made into paste with a little glycerine; amalgamate this with the paper and cotton mixture as thoroughly as possible, and submit to strong pressure or rolling.

CELLULOSE in any form, whether made from cotton, linen, wood, or other vegetable fibrous substance, affords a basis which can be treated with dilute acid to produce a horny or parchment-like substance. A modification of this is seen in making celluloid with camphor. These modified forms of organic creation can be combined with other organic substances or minerals in great variety. Thus glycerine, and at times oil of different kinds, in such admixtures confers elasticity, or a diaphanous appearance; ivory-dust has an affinity for oil and glue; and these all combine with parchment, boiled ivory-dust, and fibrine or cellulose.

Certain marine plants, such as _kelp_, yield a fibrous substance which has very peculiar qualities, and which admits of ingenious combination. Certain experiments and observations convince me that there is here a vast field, as yet unexplored, in which science will yet make discoveries and afford valuable contributions to technology.

The reader who is specially interested in this subject may consult to advantage _Die Verarbeitung des Hornes, Elfenbeines, Schildpatts und der Perlenmutter_, &c., von Louis Edgar Andés; Vienna, A. Hartleben, price 3s.

REPAIRING AMBER

HOW TO PERFECTLY RE-JOIN BROKEN AMBER, AND TO IMITATE IT--HOW TO MELT AMBER IN FRAGMENTS TO A SINGLE BODY

Amber has been admired in all ages and everywhere from its exquisite colour and semi-transparency. Many superstitions were attached to it, and many still believe that to carry a bead made from it is good for the eyesight. It is principally found on the Prussian coast, off the German Ocean, but is also picked up in considerable quantities on the English shore. It is the gum or resin of a now extinct species of pine, which was probably much like that in New Zealand, which produces the gum _kauri_, which so much resembles amber.

Some amber is yellow and clear like lemon-candy. This is extensively imitated for cigar-holders and pipe-mouthpieces, beads, &c. Then there is the clouded, varying from white to straw-colour, and the beautiful golden-brown, which appears so rich in sunlight; also the dark-brown and black. These dark-brown ambers are generally seen in old ornaments, and are of a kind which is dug out of the earth. Light amber can be darkened to brown by an artificial process.

Gum _copal_, which comes from Africa, much resembles amber, but is less beautiful and more brittle. Gum _kauri_, from New Zealand, is very much like it. Both are used to imitate amber.

There are not many who know how to mend amber when broken. I am assured that the following is a trustworthy method:--Warm the pieces, dampen them with caustic potash (_ætz-kali_), and then press them together. When well done the joining will not be perceptible. It is said that by this process small pieces of amber, amber-dust, &c., can be made into blocks.

In imitating amber, the best pieces of copal are picked out, put into an air-tight vessel, and dissolved in petroleum, sulphuric ether, or benzole. After being dried in blocks this is submitted to a great pressure. As it dries the pressure is increased.

It occurred to me many years ago that the proper way to unite copal to a tough body like amber would be to use a tough or flexible varnish as a binding medium. I find by the work of LEHNER on Imitations that he has verified this by experiment. What is also important is, that the process of hardening by pressure is by this means very much facilitated. I should judge, by all chemical laws, that a varnish infused with glycerine in combination with copal, kauri, or amber-dust would, even without pressure, form in time a substance quite as hard as amber, and much less brittle. It is to be desired that some technist would experiment on a variety of gums in this manner, and thus _fix_ or render permanent their beauty. There is a wide field here to be worked. The subject of meerschaum and amber is fully treated in a work entitled _Die Meerschaum- und Bernstein-Fabrikationen_, von G. M. Raufer; Vienna, A. Hartleben, 2 marks.

I may add that carving amber is a very elegant art, yielding beautiful results. I have known a young lady, the late Miss Catherine L. Bayard, who excelled in it. It is effected chiefly with fine files and emery or glass paper, as, owing to its extremely brittle nature, there is much risk for any save experts to use cutting tools. Amber is a very expensive material, but objects made from it are of more than proportionate value. Those who would practise carving it should begin with pieces of copal. As I have already explained, small fragments and the dust of both amber and copal can be melted and combined with clear turpentine into large masses, which are even tougher than the native gums.

An inferior, but still very pretty, imitation of amber can be made by combining almost any gum properly clarified and coloured; as, for instance, gum-arabic or dextrine with gelatine (best quality white) and glycerine. If thoroughly well combined and dried, this will wear as well as amber. Some of the gums of fruit-trees--_e.g._, of the peach and cherry--are very beautifully coloured and clear, and seem to be admirably adapted to be hardened by the same process. They occur very frequently in old books of recipes as adhesives or cements. Perfectly clear glue or gelatine with glycerine and transparent dyes form an excellent imitation for beads.

INDIARUBBER AND GUTTA-PERCHA

MENDING INDIARUBBER SHOES AND MAKING GARMENTS WATERPROOF, WITH OTHER APPLICATIONS

Indiarubber or gutta-percha enters into so many familiar and useful objects that there are few people who would not like to know how to repair them when injured.

Like the brittle or non-elastic gums, caoutchouc (with which I include the nearly allied gutta-percha) is greatly modified by admixture with certain pulverised substances, which form with it a partly mechanical, partly chemical, combination. Those who would thoroughly study the subject in all its relations may consult _Kautschuk_ (_Caoutchouc_) _und Guttapercha_, von Raimund Hoffer; Wien, 1892, Hartleben.

Caoutchouc is partially soluble in carburetted sulphur, ether, pure petroleum, or benzole, but gutta-percha is perfectly so. In this state it may be applied as a varnish or coating for repairs, as it hardens by exposure to the air. When mixed with sulphur and exposed to a heat of 110° to 115° centigrade, gutta-percha becomes what is called “vulcanised,” assuming a very light grey colour, is more elastic, and retains this elasticity at a much lower grade than before. When the heat is raised to (maximum) 180° the mass becomes very hard, tough, and black, or like horn. The conditions of its toughness, elasticity, and hardness depend upon the amount of sulphur used; as in other combinations, the harder the material becomes the less elastic it is--that is, the more brittle.

EBONITE is extremely hardened caoutchouc. It is first treated with chlorine, washed with sulphate of soda infused in water, and finally mixed with hardening substances and submitted to severe pressure.

As indiarubber or “gum” shoes are in general use, most people would consider them the proper objects to begin with. To do this, first make two separate preparations as follows:

I.

Caoutchouc 10
Chloroform 280