Page:Popular Science Monthly Volume 41.djvu/527

Rh thousand of them, and they have to be changed with every variation in the style. Originally shoe-lasts were whittled out of rough blocks of wood by hand, but in 1815 Thomas Blanchard, well known in his day as an inventor, devised a lathe for turning them out by a less laborious process. A pattern had first to be made, and then this and a block of wood were fixed on the same axis and made to revolve around a common center in a swinging lathe by a pulley and belt on one end of the axis. The cutting wheel turned on a horizontal axis, and to it were attached a number of irregular cutters which acted like gouges when the wheel was set in motion. This wheel was placed opposite the block, while opposite the pattern was a friction-wheel of the same size. By the combined movements of this axis and a sliding carriage the irregular surface of the pattern caused the axis on which the friction-wheel was to alternately approach and recede, and this motion was in turn communicated to the knife-wheel. The result was that a duplicate of the pattern was produced from the block of wood. The last lathe has been improved since in many ways, but they are all based on the principles introduced by Blanchard.

It is impossible to more than name some of the other machines which have been introduced and which have done much to hasten the manufacture and reduce the cost of foot-wear. The sole-die machine was introduced about 1851, operated first by foot-power and later by steam. The buffing machine, a sanded cylinder for the purpose of giving a velvety finish or "nap" to the bottom of the sole, followed in 1855, and the eyeleting machine in 1864. Other machines of more recent date are the beating-out machine, between the forms of which the sole of the shoe, after the channel groove has been filled with naphtha cement, is subjected to enormous pressure; the trimming machine, whose revolving knives remove the rough edges of the sole; the burnishing machine, and the heeling machinery. It can not but be a source of gratification to Americans that the most of these inventions have had their origin on this side of the ocean, and that those that did not so originate have received their greatest development here. The experiments in England with the sewing and nailing machines had not enough success to warrant any serious claim to the invention. The American shoe-factory is the triumph of American ingenuity. There is no better word than "ingenuity" to describe it. It stands for the discovery of no new principle in mechanics. It represents the utilization of no new force in Nature. But it does contain within it some of the most remarkable adaptations of mechanical principles already known and the most marvelous devices for supplanting the work of the fingers. A modern shoe-factory would make a fitting monument for the Patent Office.

To realize how the introduction of machinery into the tanning