Too much importance cannot be attached to properly controlling the tension of the rubber warp. On its uniformity depends not only the quality, but also the cost of the web. The greater the weight of slack rubber woven into the web the more costly it becomes and the poorer the quality. A very accurate sense of touch is required in testing the tension of the rubber threads as they are being delivered into the goods. The rubber warp requires the highest possible tension before breaking or chafing of the thread takes place. Each rubber thread should be under this high tension so that when the goods come through the press roll the desired contraction will take place uniformly, and a flat piece of web will be produced that will have plenty of life. It must always be remembered that the individual threads of rubber which constitute a rubber warp will act as a series of small springs, working in unison with each other. Each one should have equal power to contract the fabric at its own particular part. If any one of these strands or springs is chafed and weakened, it lessens the contracting power, and the result is that the weakened or less contracted part is of relatively greater length than the parts where the rubber threads have retained their full power. Moreover, the appearance of the goods will be spoiled by the chafed particles of rubber pricking through the face, particularly on the white and lighter colored goods. Before such webs can be marketed they must be subjected to a buffing operation to remove these dirty particles, which is accomplished by passing them over a highly speeded, cloth covered roller, which will remove the loose particles by friction and high velocity. But this operation adds to the cost. A high and uniform tension of the rubber warp is so important that most manufacturers keep men specially employed in the testing of the threads, instead of leaving this matter to the weavers. These testers acquire such a keen sense of touch that they can obtain very economical and satisfactory results. Talc or soapstone is freely used as a lubricant to reduce the risk of chafing and breaking of the rubber threads. The warps are arranged so as to allow the threads to pass through a bed of plush, loaded with talc, which adheres to the rubber threads and makes them work very smoothly. This is especially important in damp weather, which is the worst condition for the weaving of elastic goods. At times factories have stopped operations when the weather was especially humid. LET-OFF MOTION [Illustration: Fig. 1.—Individual Take-Up Motion for Wide Space Looms] [Illustration: Fig. 2.—Individual Rubber Warp Let-Off Motion]