Page:Popular Science Monthly Volume 41.djvu/525

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was largely to that class of work that the McKay machine was turned.

The close way in which the McKay machine was held tended to check further improvements for a time. The suggestions afforded by it and its success, however, were open to all, and several inventions were later offered to the public. Most important among these were the Goodyear and McKay machines for welted PSM V41 D525 Insole channeler.jpgFig. 12.—In-sole Channeler. sewing, the first mechanism for stitching the soles on lasted shoes. In Fig. 5, which represents a section of a boot, a is the upper, b the in-sole, and c the out-sole, while d is the welt, e the stitching of the sole to the welt, and f the stitching of the upper to the same. Following the process of lasting—that is, after the upper has been carefully drawn over the last—the welt is put in position around the sides up to the heel. The thin edge of this is then caught together with the upper and inner sole. The outsole is afterward tacked to the insole and, through a narrow channel made around the edges of it, sewed to the welt. The difficulties in the way of getting a machine which would do this, not simply as well as the hand, but do it at all, were many. The method which finally succeeded originated in a patent secured in 1862, by August Destory, for a curved-needle machine for sewing out-soles to the welts; but the machine did not work satisfactorily until it was taken in hand by Charles Goodyear, the son of the inventor of the India-rubber processes. This machine simply transforms the swinging movements of the hand and forearm in sewing into lateral and vertical ones, but the principle in the two operations is identical. There is one difference which in a way may be said to be even a point in favor of the machine sewing. In hand sewing the thread is drawn clear through its full length each time, and thus is weakened by constant wear. In the machine, only so much is drawn through as is necessary to form the stitch. These machines have been perfected and multiplied until what is known as the Goodyear system is the result. This system includes machines for sewing the welt on, attaching the sole to the upper, for lasting the upper, for