_Tyrian Purple._—The most highly prized ancient dyestuff, and one concerning which much interest has always been felt, was the so-called “Tyrian purple.” This was obtained from the juices of certain species of snails found in the waters of the Mediterranean Sea, and, indeed, in the ocean waters of many other warm climates. Two species of this class—the _murex Brandaris_ and the _murex trunculus_—were used extensively by the ancients, and great mounds of their shells, such for instance as the so-called Monte Testaccio at Tarentum, are still found along the shores at places famous, in old days, for their dyeing establishments. Other shellfish of the same general type, known as _purpura lapillus_, are found quite abundantly, not only in the Mediterranean, but also on our own coast and along the shores of Central and South America. They have been used by the natives in Nicaragua and elsewhere, from time immemorial, for obtaining a similar color. [Illustration: _Purpura lapillus_ _Murex trunculus_ _Murex Brandaris_ FIG. 1—SHELLFISH USED BY THE ANCIENTS FOR TYRIAN PURPLE] These shellfish were so much sought after in the old days that, by the time of the early Middle Ages, they were almost exterminated, and the dye disappeared from commerce entirely. But, long before that, in the early days of the Roman Empire, the coloring matter was so expensive that fabulous sums were paid for cloth or yarns dyed with it, and its use was practically confined to the imperial family. In fact one of the imperial titles in the Eastern empire—_purpureogenitus_, “born to the purple”—was due to this fact. Some interesting information upon the value set on this dyestuff by the ancients is afforded by the so-called Edict of Diocletian, fragments of which, engraved on stone tablets, have been found in different parts of the old Roman Empire, ranging from Egypt to Asia Minor. By this edict, issued in A.D. 301, the emperor Diocletian attempted to fix the market price of the principal articles of commerce, for the Eastern empire. According to this, the price of wool, heavily dyed with this color, was worth about $350 a pound, in gold. The dyestuff, as we learn from the description of the process by ancient writers, was obtained from a whitish or yellowish liquid found, two or three drops at a time, in a particular vein in the body of these animals. This juice, when exposed to air and especially to sunshine, forms the purple or violet color, much in the some manner that the blue color of indigo is formed from the yellow juice of the indigo plant. The shellfish in question, having for many centuries been left undisturbed, are now quite common in the waters of the Mediterranean, and are occasionally to be found in the poorer quarters of Venice and other Italian seaports, exposed for sale as food.