It does not appear that any good method is known by which a discoloured ivory can be bleached. All rough usage of course merely injures the piece itself, and removes the external surface. Exposure to the light keeps the original whiteness longer, and in a few instances may to some extent restore it. It need hardly be observed that any other attempt to alter the existing condition, whatever it may be, as regards the colour of an antique or mediæval ivory is to be condemned.
It is quite a different matter to endeavour to preserve works in ivory which have suffered partial decomposition, and which can be kept from utter destruction only by some kind of artificial treatment. Almost all the fragments sent to England by Mr. Layard from Nineveh were in this state of extreme fragility and decay. Professor Owen suggested that they should be boiled in a solution of gelatine. The experiment was tried and found to be sufficiently effectual; and it is to be hoped that the present success will prove to be lasting. “Since the fragments have been in England,” says Mr. Layard, “they have been admirably restored and cleaned. The glutinous matter, by which the particles forming the ivory are kept together, had, from the decay of centuries, been completely exhausted. By an ingenious process it has been restored, and the ornaments, which on their discovery fell to pieces almost upon mere exposure to the air, have regained the appearance and consistency of recent ivory, and may be handled without risk of injury.”
We may think it to be sufficiently strange in tracing the early history of the art of carving or engraving in ivory, that we should be able easily to carry it, upon the evidence of extant examples, to an antiquity long before the Christian era: through the Roman, Greek, Assyrian, and Jewish people, up to an age anterior to the origin of those nations by centuries, the number of which it may be difficult accurately to count. These very ancient examples are of the earliest Egyptian dynasties: yet, between them and the date of the earliest now known specimens of works of art incised or carved in ivory there is a lapse of time so great that it may probably be numbered by thousands of years.