The name is thought to have derived from a mispronunciation of twill (or tweel, as filtered through the Scottish accent), which describes a fabric with a diagonal weave, whose irregular appearance derived from the weaving of two or three weft threads instead of just one. Since this method was used in the major textile centers that stood in the nineteenth century along the river Tweed, which separates Scotland from England, and which would help to explain the confusion. Tweed is world-famous for its robust construction, which ensures its great durability and long life. At first, grey and black threads were used, and the classic motif was herring-bone. Today it is produced in many colors and patterns. Harris tweed is a special variety made famous by the Dowager Countess of Dunmore who encouraged it among the manufacturers of tweed on the islands of Harris, Lewis, Uist and Barr, in the Outer Hebrides. The label Harris Tweed guaranteed that the cloth was made from pure virgin wool, carded, woven, spun, and hand-dyed with plant dyes by the inhabitants of those islands. Nowadays it is no longer an artisanal fabric; instead it is produced in some 600 mills, in a quantity of nearly three million meters per year. Excellent in quality, with its distinctive light-dark pattern, especially in herring-bone, and in a vast array of colors, it differs from normal tweed because it is rougher. Harris Tweed became a registered trademark in 1909 and the logo, a globe, is taken from the Dunmore family crest. Donegal (or Irish tweed) is another type of tweed, originating from County Donegal in Ireland. Linton tweed, produced by the English Linton company, founded in 1919 by William Linton, was used in haute couture by such fashion designers as Chanel and Schiaparelli, as well as Dior, Balenciaga, Courrèges, Balmain and Saint-Laurent.