PURPURA, in natural history. See MUREX: where we have given an account of the Tyrian method of dyeing purple with a liquid extracted from the fish. It has been affirmed, however, that no such method was ever practised. "At Tyre (says Mr Bruce) I engaged two fishermen, at the expence of their nets, to drag in those places where they said shell-fish might be caught, in hopes to have brought out one of the famous purple-fish. I did not succeed; but in this I was, I believe, as lucky as the old fishers had ever been. The purple fish at Tyre seems to have been only a concealment of their knowledge of cochineal; as, had they depended upon the fish for their dye, if the whole city of Tyre applied to nothing else but fishing, they would not have coloured 20 yards of cloth in a year."