The methods of preservation which have been described in the preceding pages may be thus tabulated and summarised:

There will be no difficulty in the choice of methods for limestone or earthenware, whether kiln-dried or sun-dried, for a simple experiment will prove whether steeping is likely to cause injury or disintegration.

The methods are themselves simple and inexpensive. For organic substances the chief question is the choice of the most suitable medium for impregnation.

Iron and bronze present some difficulty, although the use of a file will readily show whether reduction is feasible.

The simplicity of the apparatus required for Krefting’s method gives it an advantage over other methods, at any rate for iron objects. Objection has been taken to the methods of reduction, because they give to the objects thus treated an appearance to which the public are not accustomed. It may be safely asserted however that this appearance more truly represents the object when in actual use, than the oxidized and rust-covered specimens to which we are accustomed in antiquarian collections. To those who value an antique object for the crust that covers it, all methods of restoration must be objectionable. Such persons ought to object to the removal of the incrustations which hide the cuneiform inscriptions on clay tablets. On the other hand, those who regard these methods with approval should go a step further and confide their collections to experienced hands for some form of treatment which may bring to light inscriptions and inlaid work which will greatly enhance their value.

To spread the knowledge of these methods and to invite the co-operation of others is the aim of this book. As to the best method to be used in each particular case it is unnecessary to lay down any hard and fast rule, for this can only be learned by observation and experience.

APPENDIX A.
METHOD OF TAKING SQUEEZES OF INSCRIPTIONS, ETC.

For this purpose a proper brush is required with strong bristles, closely set as in a scrubbing brush; the brush should have a firmly fixed handle, preferably slightly curving upwards to save the knuckles from being bruised upon the stone. A so-called “silver brush” will serve the purpose. The paper should be stout and stiff enough to resist the blows of the brush without tearing. An admirable paper, which possesses these qualities, is specially prepared for the purpose by the O.W. Company, 100, Great Russell Street, London, W. As a substitute for the specially prepared paper stout packing paper may be used with satisfactory results.

The stone should be tilted if possible at an angle of about 45°, and the surface bearing the inscription should be well washed or carefully scraped free of dirt and foreign matter and should be rendered thoroughly wet. A piece of the special paper of suitable size should be soaked in water for a minute or more. It should then be carefully applied to the surface of the stone in such a way as to prevent air-bubbles. This may be assisted by gently smoothing it with the hand or back of the brush. When close adhesion has been secured, and all air-bubbles removed (this can sometimes be done by pricking through the paper with a pin), the paper should be sharply beaten with the brush, the blows being delivered from the wrist and not from the shoulder until it begins to show a fluffy appearance. It should then be peeled off and allowed to dry, after which it may be rolled or folded without danger of injury to the embossed inscription.

Should the paper tear, another piece soaked as before may be placed on the top and beaten until it becomes incorporated with the first. If the letters are large and deep, or if the surface is much cracked, two or more sheets superimposed should be used. In the case of large inscriptions it is advisable to take impressions by sections, care being taken that each sheet slightly overlaps the preceding one to prevent the possible omission of some of the letters.

It is also useful to take at the same time a pen or pencil copy of the inscription, for a comparison of the copy and the squeeze will often prevent errors in deciphering. The squeezes can be very well deciphered by artificial light, while doubtful letters may sometimes become clear on holding up the sheet to the light. The reverse side of the squeeze, upon which the inscription stands in relief, may afford great assistance when read by the aid of a mirror. A photograph of the squeeze will often reveal more than a photograph of the inscription itself.

The method is described by S. Reinach in his “TraitÉ d’Épigraphie Grecque” (Introduction, p. XX. ), where he also refers to HÜbner, “Ueber mechanische Copien von Inschriften,” 1871.

APPENDIX B.
ZAPON.

Further particulars may be given of the new preparation known as Zapon. This substance is now made on a large scale, and can be obtained from the British Xylonite Co., Brantham Works, Manningtree (Xylonite lacquer F. 6631). The following excerpt is from a short communication in “Prometheus” (XV. 1904, pp. 485 and 499), which deals with the preservation of wax seals and of glass.

Zapon, the invention of Crane, of Shorthills, U.S.A., has been used for 20 years past for the protection of metals from oxidation and the action of sulphuretted hydrogen. Although the products of the various manufacturing firms differ in composition, zapon is essentially a solution of nitro-cellulose in various solvents. The nitrated cellulose, i.e. gun-cotton (pyroxyline), is generally, with the addition of camphor, dissolved in a mixture of amyl acetate (hence the peardrop-like smell) to which distillation products of petroleum, etc., are added. It comes into the market as a faintly yellow, slightly oily liquid. Its use as a preservative depends upon the fact that the evaporation of the solvent leaves behind it a fine transparent coating of gun-cotton (pyroxyline). Zapon for preservative purposes must have a neutral reaction, and must not under any circumstances redden litmus paper. Its use in this connection is due to Schill, who also recognised its suitability for other materials, as, for example, for plaster casts, the treatment of which is eminently simple, for it consists in dipping small casts, or in painting larger ones with a soft brush. It is advisable to begin at the top and apply it from above downwards, using a clean dry cloth to wipe off any excess of the fluid which collects in the deeper parts of the cast. If zapon containing about 4% of gun-cotton is used, the coating left on drying is scarcely visible; with a 5% solution a certain degree of polish results. Casts treated with zapon are less easily damaged by dust than those untreated, and may be cleaned with soap and water without injury to their surface, provided that a soft brush is used, but brushes which are stiff enough to injure the zapon coating will damage the contours of the statue. It should only be used for objects kept under cover, for rain and wide variations of temperature will attack them almost as readily as untreated casts. It can be used with equal success for antiquities of stone, clay, baked or unbaked, or for plaster after the soluble salts have been thoroughly removed by steeping, for if this has not been done the salts will soon crystallize out and loosen the protective coating. For objects which are free from salts impregnation with zapon possesses the advantage that it renders them less liable to damage from handling or dust, whilst the appearance is scarcely altered, if at all. This applies also to antiquities of metal, for unless the injurious chlorine compounds are removed by simple steeping, or reduction and subsequent steeping, treatment with zapon is useless. To bronzes, which in spite of mechanical cleaning show a somewhat unpleasant grey non-metallic appearance, zapon often imparts a distinct metallic lustre. To enhance this lustre by a second vigorous application is not recommended, for this gives the impression of a varnish. To protect articles of silver from the blackening influence of sulphuretted hydrogen, zapon is very useful, but does not afford absolute protection unless it has been thickly applied. In collections of armour much use may be found for this material. The objects are dipped and then placed in a drying oven at 105°F. [40°C.] to secure rapid drying and uniform distribution. The amyl acetate or other solvent is best conducted away, as it evaporates, into a flue or into the open, although the vapours can hardly be considered dangerous to health.

The following references will afford some information on the use of zapon in the preservation of Archives:

E. Schill, “Anleitung zur Erhaltung und Ausbesserung von Handschriften durch Zapon-ImprÄgnierung,” Dresden, 1899.

O. Posse, “Handschriften Konservirung,” Dresden, 1899.

G. Sello, Das Zapon in der Archivpraxis (“Korrespondenzblatt des Gesamtvereins der deutschen Geschichts- und Alterthumsvereine,” L., 1902, p. 195).

Schoengen, Over hat Zapon (“Nederl. Archivenblad,” 1902, 1903, Nos. 1 and 3).

J. Perl, Das Archiv-Zapon (“Korrespondenzblatt,” LII. , 1904, pp. 119 and 435).

G. Sello, Die bei der Zaponverwendung in der Archivpraxis gemachten Erfahrungen (“Korrespondenzblatt,” LII. , 1904, p. 439).