A curious quid pro quo appears in a fifteenth century treatise on gems written in French. Here, in a list of engraved gems suitable for use as amulets, we read, “If you find a dromedary engraved on a stone with hair flowing over its shoulders, this stone will bring peace and concord between man and wife.” The original Latin text read, “If you find Andromeda on a stone with hair flowing over her shoulders,” etc.[202] The translator’s art which could turn Andromeda into a dromedary almost equalled that of the enchantress Circe. A few even of the early writers were disposed to be sceptical as to the virtues ascribed to these engraved gems, and did not hesitate to assert that the Greek and Roman engravers executed their designs for ornamental purposes rather than to fit the gems for use as talismans. This was undoubtedly true in a large number of cases but nevertheless, as we have seen, many engraved talismans were really cut in the early centuries. As the art of gem engraving was not practised in the Middle Ages, some medieval writers suppose that the engraved talismanic gems current in their time were not works of art, but of nature, and Konrad von Megenberg accepting this view, gave it as his opinion that “God granted these stones their beauty and virtue for the help and comfort of the human race,” adding that when he hoped to receive help from them he in no wise denied the grace of God.[203] Damigeron writes of the sard that, if worn by a woman, it is a good and fortunate stone. It should be engraved with a design showing a grape-vine and ivy intertwined.[204] A celebrated topaz was that noted by George Agricola as being in the possession of a Neapolitan, Hadrianus Gulielmus.[205] It bore, in ancient Roman characters, the terse and pregnant inscription: Natura deficit, Fortuna mutatur. Deus omnia cernit. This was very freely rendered by Thomas Nicols as follows:[206] Nature by frailty doth dayly waste away. Fortune is turn’d and changed every day. In all, there is an eye know’s no decay. Jah sees for aye. There is in the Imperial Academy at Moscow a turquoise two inches in diameter, inscribed with a text from the Koran in letters of gold. This turquoise was formerly worn by the Shah of Persia as an amulet, and it was valued at 5000 rubles by the jeweller from whose hands it came.[207] It is well known that Napoleon III was inclined to be superstitious, and there is not, therefore, anything inherently improbable in the report that he left the seal he wore on his watch-chain to his son, the unfortunate Prince Imperial, as a talisman. This seal is said to have borne an inscription in Arabic characters, signifying “The slave Abraham relying on the Merciful One (God).”[208] The talisman lost its virtue on that unlucky day when, in far-off Zululand, the heir to so many hopes was cut off in the first flush of early manhood (see page 64). V On Ominous and Luminous Stones THE OPAL