Some years ago, when crossing the Kasr-el-Nil bridge, a youth of the fellaheen class edged up to me and asked if I would purchase some seals. He said, “I have some very good ones.” I asked to see them and he produced one. I knew very little about seals, but thought there was no harm in buying a few. In the end I spent 8s. upon them, and when I got home examined them carefully. Apparently some of them were made of carnelian and had the characteristic marks of the stone, though they were considerably weathered.
One does not show antiquities in the frank manner that is common to other hobbies, so I put one in my pocket, and placed the others away in a safe drawer. Some days went past, and then my opportunity came. I was in the shop of a dealer noted for his keenness in detecting frauds, and after discussing various objects with him, I said, “Oh, I came across a seal the other day. Just look at it, will you?” and I casually passed it over the counter to him. He examined it carefully, and then a grim smile overspread his face. “How much did you pay for it?” “I paid 8s. for a lot,” I replied. “Oh, well then, you need not grumble, for they did me out of as many pounds as you paid shillings,” said the dealer. The seals were imitation, very cleverly made of glass, and rubbed with sand to produce the appearance of age.
Ancient Pigments
Ancient pigments always show at some part the unfaded colour. There is no such thing as uniform degradation of colour. There should be no general appearance of decay. The ancient things were made of fresh material, and were preserved carefully.
Egyptian blue is composed of sand, copper oxide, and soda, mixed together, ground finely, then moistened with water, tied up in a tiny bag the size of a walnut, put into a furnace and heated to the temperature of red-hot copper. This must be done in a small furnace, and the temperature must not be carried too high, or an ordinary green glass will result. The temperature must be just enough to fuse the copper, soda, and silica into what is called a frit, that is, the stage which immediately precedes the fusion of the ingredients which would result in glass. The ball of frit is taken out and pulverised, mixed with glue or gum arabic, and used as a paint. The depth of colour decreases if the paint is ground too finely.
The green colour is either the natural green ore (malachite), or an oxide or artificial carbonate.
The purple colour is manganese oxide.
The red colour is simply earthy hæmatite or iron oxide.
The black colour is either carbon or black oxide of iron, or both mixed together, or the black oxide of manganese.
The yellow is plain yellow ochre, sometimes mixed with a little white.