Page:Popular Science Monthly Volume 16.djvu/652

 machines, seriatim, he is able to arrive at a classification of them, according to the kind of work which it does. Thus he finds one set carding the cotton-wool supplied to it, so that its confused tangle gives place to a parallel laying of the fibers. He would see another taking up the bundles of carded wool, and drawing them out (after repeated doublings to secure uniformity) into a long, soft cord. This cord he would then trace into the roving-machine, which, by a continuation of the drawing process, further reduces its thickness, at the same time giving it a slight twist to increase its tenacity, so that it admits of being-then wound upon bobbins. Thence he would trace the cord into the spinning-machine, which at the same time stretches and twists the cord, producing from it a yarn whose fineness might vary considerably in different machines. Finally, he would see the spun yarn carried, some as weft and some as woof, into the power-loom, from which it emerges as woven cloth—the final resultant of the whole series of operations.

Concentrating now his attention upon any one of these machines, he studies its wheels, levers, and other moving parts, and tries to comprehend their several actions and the bearing of these upon each other. By long and scrutinizing observation he masters the whole series of sequences, and traces the distribution of motion from a single large axis, through the hundreds (it may be) of separate pieces of the machine directly or indirectly connected with it; and he might thus frame a description of the working of the machine, which might be perfectly correct so far as it goes, and which yet would be defective in one most essential particular—the statement of the force or power by which it is moved. For, so far as mere visual observation could teach him, the machine might be self-moving; and he might thus attribute to each kind an inherent power of carding, roving, drawing, spinning, or weaving, as the case might be.

Carrying his observations further, and noticing that one or another of these machines comes to a standstill, but resumes its motion after an interval, he may include this occasional suspension also in his general expression; but, perplexed by the want of any regularity in its intervals, he will seek some further explanation. Continuing his patient watch, he will see that the stoppage of the machine follows the pulling of a handle by the man in attendance upon it, and that, when the handle is pulled the other way, the machine goes on again; and thus he will be led to introduce a certain position of this handle as one of the antecedent conditions of the machine's action. Still pursuing-his inquiries, he finds out that the axes of the several machines are all in mechanical relation with one great longitudinal shaft, being connected with it either by continuous bands passing around pulleys, or by trains of wheelwork; and at last he discovers the important fact that the movement of the handle which stops the machine breaks the continuity of that relation, shifting a strap from a "fast" to a "loose"