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:—

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.