The weaving operation begins when the warp, or the longitudinal threads of the piece to be woven, has been fixed in position on the loom. The threads used for the warp are what in spinning are called "twist." These long threads, or "ends" as they are sometimes called, when placed on the loom pass through the openings of the "reed," a sheet of metal cut like a comb into spaces of the width required for the special coarseness or fineness of the material to be woven. The twist also passes through loops known as "healds." Thus the first element to be taken into account is the thickness of the threads of the warp, the number of threads going to make up an inch of width, and the total width of the piece to be woven. The work of the loom is to throw across the warp the cross threads or "weft." These threads are carried in the shuttle which flies to and fro and passes over and under the warp threads alternately, or at such angles and intervals as are provided for by the arrangement of the warp in the "healds" and "reed." The weft or cross threads are termed "picks." Thus the second element in determining the price is the fineness and closeness of the weft. The fineness is determined by the number of counts of the yarn. The closeness may be determined by counting the number of threads or picks in a given length actually woven, or by a calculation based upon the mechanical action of the machine. In many cases the number of picks can be easily settled by counting, but in almost every instance the most exact method is by calculation, based upon the sizes and divisions of the wheels and of the "beam" in the loom. The "beam" is the bar or pole round which the cloth is rolled in process of weaving. The third element is the total length woven, and a fourth is the nature and quality of the material used. This latter is an especially important element in price. The smaller the openings in the "reed" through which the threads pass, the finer and closer the crossing of the weft, the greater in number and more delicate are the threads to be watched by the weaver, and the greater is the liability to breakage of threads. Closer attention and greater dexterity are needed in the weaving of fine than of coarse materials, but on the other hand the weaving of the coarser yarns may mean harder physical labour though not requiring so much skill. The harder work is paid for at an increased rate, though less wages may be earned by the operative.