When the Vienna Exposition, in 1873, was held, a great advance was shown in this and all other classes of agricultural machinery. Reapers and mowers were lighter in construction, and far less in cost, and stronger and more effective in every way. The old original machines of McCormick on which he had worked for twenty years prior to the 1851 triumph, had been succeeded by another of his machines, on which an additional twenty years of study, experiment and improvement had been expended. An endless number of inventors had in the meantime entered the lists. The frame, the motive gearing, the hinged cutter-bar and knives, the driver’s seat, the reel, the divider, for separating the swath of grain to be cut from the uncut, the raising and depressing lever, the self-raker, and the material of which all the parts were composed had all received the greatest attention, and now was awaiting the coming of a perfect mechanical binder that would roll the grain on the machine into a bundle, automatically bind it, and drop the bound bundles on the ground. The latter addition came in an incomplete shape to Vienna. The best form was a crude wire binder. In 1876 at the Centennial Exhibition at Philadelphia, the mowers and reapers blossomed still more fully, but not into full fruition; for it was not until two or three years thereafter that the celebrated _twine_ binders, which superseded the wire, were fully developed. Think of the almost miraculous exercise of invention in making a machine to automatically cut the grain, elevate it to a platform, separate and roll it into sheaves, seize a stout cord from a reel, wrap it about the sheaf, tie a knot that no sailor could untie, cut the cord, and throw the bound sheaf to one side upon the ground! So great became the demand for this binders’ twine that great corporations engaged in its manufacture, and they in turn formed a great trust to control the world’s supply. This one item of twine, alone, amounted to millions of dollars every year, and from its manufacture arose economic questions considered by legislators, and serious litigation requiring the attention of the courts. At this Centennial Exhibition, besides twenty or more great manufacturing firms of the United States who exhibited reapers and mowers, Canada, far-away Australia, and Russia brought each a fine machine of this wonderful class. And not only these countries, but nearly all of Europe sent agricultural machines and implements in such numbers and superior construction that they surpassed the wildest dreams of the farmer of a quarter of a century before. Up to this time, about eleven thousand patents have been granted in the United States, all presumably on separate improvements in mowers and reapers alone. This number includes, of course, many patents issued to inventors of other countries.