extraordinary size and richness of colour, and had a turquoise de la vieille roche that was the envy of all the connoisseurs.

He discovered wonderful stories, also, about jewels. In Alphonso's Clericalis Disciplina a serpent was mentioned with eyes of real jacinth, and in the romantic history of Alexander, the Conqueror of Emathia was said to have found in the vale of Jordan snakes "with collars of real emeralds growing on their backs." There was a gem in the brain of the dragon, Philostratus told us, and "by the exhibition of golden letters and a scarlet robe" the monster could be thrown into a magical sleep and slain. According to the great alchemist, Pierre de Boniface, the diamond rendered a man invisible, and the agate of India made him eloquent. The cornelian appeased anger, and the hyacinth provoked sleep, and the