ng to the principle of the use of outlines of different colours
defining and relieving the different forms in the pattern upon different
grounds. The rectangular influence arising from the technical conditions
of the work gives a definite textile character to the design which is
very agreeable; besides, as a question of line and form, in a carpet or
rug which is rectangular in shape and laid usually upon rectangular
floors, the squareness of form harmonizes with the conditions and
surroundings of the work in use. The Persian designer, indeed, appears
to be so impressed with this feeling, that he uses a succession of
borders around the central field of his carpet or rug, still further
emphasizing the rectangularity; while he avoids the too rigid effect of
a series of straight lines which the crossing of the threads of the weft
at right angles to the warp might cause, by changing the widths of his
subsidiary borders and breaking them with a constant variety of small
patterns, and inserting narrow white lines between the black lines of
the border.

[Illustration (f127): Sketch to Illustrate Treatment of Borders in a
Persian Rug.]

[Effect of Texture on Colour]

In tapestry the effect of the emphatic warp worked vertically in the
loom, but hung horizontally, has a very important influence upon the
effect. If we took a piece of paper coloured with a flat even tint, and
folded it in ridges, the quality of the tint would be at once changed,
and so in tapestry the passing of the wool of the wefts, which form the
pattern or picture, over the strong lines of the warp--which are broad
enough to take the outlines of the cartoon upon them--produces that soft
and varied play of colour--really colour in light and shade--which, over
and above the actual dyes and artistic selection of tints, gives the
peculiar charm and effect in tapestry.

This sheen and variety are more or less evident in all textiles, and a
good textile pattern only adds to the variety and richness of the
surface. The different thicknesses or planes of surface and the
difference of their texture caused by the different wefts being brought
to the surface of the cloth or silk (from the simplest contrast of
line presented by the simplest arrangements of warp and weft, to the
complexities of many-coloured silk stuffs and brocade) alone give a
value to the surface pattern.

In cut velvet the same principle of contrast of s