One of the great difficulties of the weaver is the shading off or gradation of the colours, which is rendered more difficult by the design being reproduced on the wrong side from the position of the weaver. Hatching and stippling are resorted to in order to prevent a harsh or mosaic-like appearance, and it is here that the great skill and artistic knowledge of the weaver are most required. An extraordinary number of tones and shades are used in an important piece of work, all of which require to be fast dyed in colour in order to secure durability of tone in the fabric. It is said that M. Chevreul, the late famous French chemist and director of the dyeing department of the Gobelins, had composed a chromatic prism of 14,420 different tones. The best wool used in principal tapestry works on the Continent has always been imported from Kent in England. The art of tapestry weaving was originally acquired from the East, where carpets of a floral and ornamental design were woven in the imitation of the old hand-made embroideries. In Europe the names of Sarazins or Sarazinois tapestry were given to these products from the fact that they were made and exported by the Saracens. Perhaps the earliest woven tapestries of Europe were the Flemish, which were first made towards the end of the twelfth century. The towns of Arras, Oudenarde, Lille, Brussels, Valenciennes, Tournay, and Bruges were celebrated for the manufacture of tapestry, of which the town of Arras was the most important, hence the old name of “Arras” used in England for all kinds of storied tapestry. Flanders was a rich and powerful country during the fourteenth and fifteenth centuries, and at that time the ports of Bruges and Antwerp were the greatest in the world. The various trades were protected by the great corporations or guilds against the encroachments of the nobles on their rights, and the most sturdy and turbulent of all the guilds was that of the Flemish weavers, by reason of their numbers and general prosperity of their trade. The product of the Flemish looms found its way to all parts of Europe and particularly to England, and as far as design and workmanship were concerned, and in the flat treatment of the former to the material, these old Flemish tapestries have never been excelled. The flat decorative treatment in the figure subjects of the earlier work, consisting of allegorical designs and romances by such artists as Roger van der Weyden, Stuerbout, Hugo van der Goes, and other artists of the Van Eyck school, were singularly appropriate to the material, and immensely superior to the more gorgeous effects of colour and misapplied shading of the later French tapestries. Examples of this earlier work are still in existence in the museums and palaces of Europe.