26 1 ne the outer ply 16 provides a smooth neat appearance to the bi ply fabric and provides an entrapment barrier to the inside channel ridge fabric allowing it to trap the air being held in the inside channel this speeds body moisture evaporation the inner ply 18 on the other hand provides a ridged effect with the plurality of adjacent courses of the thick yarns b providing a thicker fabric which alternates with the fabric produced by the plurality of adjacent courses of thin yarns a which is thinner this is diagrammed in fig3 wherein the thicker fabric courses are shown at 26 and the thinner fabric courses are shown at 28 in the inner ply 18 the thicker fabric sections provide ridges appearing on both the inside surface of the bi ply fabric and on the interior surface of the inner ply of the bi ply fabric the ridges in the inside surface of the inner ply 18 define the sides of channels or valleys 27 which lie against the body of the wearer and the spacing between the ridges on the interior surface of the inner ply 18 provide valleys 29 the valleys 29 are closed by the other ply 16 to provide channels within the interior of the bi ply fabric extending in a course wise direction in registry with the interior valleys 29 the valleys 27 on the inner side of the inner.