Such is a brief description of the most important of the preparatory processes of cotton spinning. There are innumerable details involving technical knowledge which fall outside the province of this story. =Drawing Frames.=--It is a very common thing for a new beginner in the study of cotton spinning to ask--what is the use of the drawing frame? As a matter of fact, the unpractised eye cannot see any difference between the sliver or soft rope of cotton as it reaches, the drawing frame and as it leaves the frame. The experienced eye of the practical man can, however, detect a wonderful difference. It has been shown that the immediately preceding operation of carding--amongst other things--reduces the heavy lap into a comparatively thin light sliver; thus advancing with one great stride a long way toward the production of the long fine thread of yarn ready for the market. No such difference can be perceived in the sliver at the drawing frame. This machine is practically devoted to improving the thread finally made in two distinct and important ways. 1. The fibres of cotton in the sliver, as they leave the Carding Engine, are in a very crossed and entangled condition, not at all suited to the production of a strong yarn by the usual processes of cotton spinning. The first duty of the drawing frame may be said, therefore, to be the laying of the fibres in parallel order to one another, by the action of the drawing rollers. 2. The sliver of cotton, as it leaves the card, is by no means sufficiently uniform in weight per yard for the production of a uniform and strong finished thread. It will easily be conceived by the readers of this story of the cotton plant that the strength of any thread is only that of its weakest portions. Take a rope intended to hold a heavy weight suspended at its lower end, and assume it to be made of the best material and stoutest substance, but to contain one very weak place in it; this rope would practically be useless, because the strength of the rope would only be that of the weakest part. The drawing machine in cotton spinning aims at removing the weak places in cotton thread, thus making the real strength of the thread vastly greater than it would otherwise be. The method by which these important objects are attained may be briefly explained as follows:-- From four to eight, but most usually six, cans of sliver from the previous machine are placed behind the frame, and the ends of the slivers conducted over special mechanism within the range of action of four pairs of drawing rollers. This passage of the cotton is shown very clearly in Fig. 17.