threads leaves the second reed, it passes partially round a small guide roller, then almost wholly round each of three cylinders arranged deg.o deg., and finally on to the loom beam.  Each cylinder is 4 feet diameter, and three of them occupy a position between the left supplementary frame, and the central frame in Fig. 29, while the remaining three cylinders are similarly disposed between the central frame and the supplementary frame of the right in the same illustration.

The number of steam-heated cylinders, and their diameter, depend somewhat upon the type of yarn to be dressed, and upon the speed which it is desired to run the yarn.  A common speed for ordinary-sized jute is from 18 to 22 yards per minute.

[Illustration:  FIG. 30 A MODERN YARN DRESSING MACHINE WITH SIX STEAM-HEATED CYLINDERS]

A different way of arranging the cylinders is exemplified in Fig. 31.  This view, which illustrates a machine made by Messrs. Charles Parker, Sons & Co., Dundee, has been introduced to show that if the warps under preparation contain a comparatively few threads, or if the banks are made larger than usual, two warps may be dressed at the same time.  In such a case, three cylinders only would be used for each warp, and the arrangement would be equivalent to two single dressing machines.  The two weaver’s beams, with their pressing rollers, are shown plainly in the centre of the illustration.  Some machines have four cylinders, others have six, while a few have eight.  A very similar machine to that illustrated in Fig. 31 is made so that all the six cylinders may be used to dry yarns from two banks, and all the yarns wound on to one weaver’s beam, or all the yarns may be wound on to one of the beams in the machine in Fig. 31 if the number of threads is too many for one bank.

[Illustration:  FIG. 31 DRESSING MACHINE FOR PREPARING TWO WARPS SIMULTANEOUSLY By permission of Messrs. Charles Parker, Sons & Co.]

Suppose it is desired to make a warp of 700 threads instead of 500, as in the above example; then 350 spools would be placed in each of the two banks, the threads disposed as already described to use as much of the heating surface of the cylinder as possible, and one sheet of threads passed partially round what is known as a measuring roller.  Both sheets of threads unite into one sheet at the centre of the machine in Fig. 31, and pass in this form on to one of the loom beams.

It has already been stated that the lower roller in the starch box is positively driven by suitable mechanism from the central part of the machine, Fig. 29, while the upper roller, see Fig. 30, is a pressing roller and is covered with cloth, usually of a flannel type.  Between the two rollers the sheet of 350 threads passes, becomes impregnated with the starch which is drawn up by the surface of the lower roller, and the superfluous quantity is squeezed out and returns to the trough, or joins that which is already moving upwards towards the nip of the rollers.  The yarn emerges from the rollers and over the cylinders at a constant speed, which may be chosen to suit existing conditions, and it must also be wound on to the loom beam at the same rate.  But since the diameter of the beam increases each revolution by approximately twice the diameter of the thread, it is necessary to drive the beam by some kind of differential motion.