Note 252 — ESSAYS. (continued 3)

It is to be regretted that Baron Bertholdy did not live to complete and publish his essay on the glass and paste of the ancients, as applied to the production of cameos, intaglios, &c., in imitation of true gems. He had collected a great mass of materials, and had had some very beautiful specimens engraved. Among other fragments, I saw in his possession, in 1819, several handles of drinking-cups, on which the maker’s name and place of residence, namely, Sidon, were stamped before the glass was cold, some in Greek, some in Roman letters.

Mr. Hatchet has analysed many of the ancient glasses and pastes; but he did not find cobalt in any of them. In some very ancient beads found in one of the oldest tombs of Egypt, he found the colouring matter was manganese. Yet Davy speaks of a blue glass which appeared to him to be tinged with cobalt as common among the ruins of Rome; and says, moreover, that on analysing different ancient transparent blue glasses, he had found cobalt in all of them.