PURPLE-SHELL. A gastropod mollusk of the genera Murex and Purpura, whose secretions give a purple stain. Certain other mollusks, as ,lanthina and Aplysia, yield a violet-hued liquor, while others, as Area, pour forth red blood. The discovery and use of this color are prehistoric and myths have arisen to explain them. Long before the beginning of the Christian era the gathering of the mollusks and application of the dye were practiced in factories all about the east ern part of the 1,1editerranean, several species of small Alurex serving the purpose—principally Murex tranceles. The most famous place of pro duction was near Tyre, whence the product came to be called Tyrian purple. It was limited in supply and costly, and from an early time—tra dition says from the era of Romulus—was re served wholly for the use of royalty in Church and State. Hence the terms and symbolism of this color as imperial, and the phrase porphyrogeni tes—'born to the purple.' I'he color is still re served in various ceremonial usages to officials of high rank. Accounts of the various tints are given by Pliny (Natural History, Vol. II., Book IX.) and by others. The most highly esteemed Tyrian hue was a deep blood-color, but full violet, heliotrope and intermediate shades were made by blending. Tarentum, in Southern Italy, also produced a famous red, and great heaps of broken shells in that neighborhood remained in 1789 to attest the importance of this ancient industry. The process was one of crushing the shell and macerating the animal. The juices were at first
nearly colorless, hut on exposure to the light and proper treatment the rich purple hue was developed. Sunlight seems to have been neces sary.
Of the mollusks other than Alurex which yield the dye, the most important is the nearly related Purpura, especially the 'dog-whelk' (Purpura levities), a shell the size of an almond or smaller, which abounds on both coasts of the North Atlantic, and which has been used from early times both in Great Britain and in New England as a source of an indelible violet ink for marking, ornamenting and even dyeing textile fabrics. The color appears to be confined to a 'vein' or gland near the head, which yields a drop of viscid liquid, which when first dropped upon the cloth, or used with a pen to draw letters or an orna mental design, is colorless, but as soon as it is exposed to the still, changes rapidly from light to deep green, to blue and at last to a fine Purplish red. "If the cloth he now washed with scalding water and soap, and laid again in the sun, the color changes to a beautiful crimson," which is permanent. This dye was extensively used in Ireland in the 15th century, for orna menting woolen's gowns in drawn designs; and was} persons made their living by this art. Con sult worts on conehology and antiquities: espe cially Lovell, Edible .11ollusea of Ureat Britain (2d. ed. London, ISS.1).