After the self-raker was introduced the next important improvement was in the binding of the grain. At first the cut grain was raked into a receptacle which was dumped by the driver of the machine when enough had accumulated to form a bundle and the bundles were bound by men following the machine. As in the evolution of the raker, the next step was to provide a platform for these men on the machine so that they could ride as they bound the grain and finally in 1873 a self-binding attachment was invented which increased the efficiency of the machine manifold. This self-binder, however, called for the use of wire which did not meet with favor as a binding material because of the difficulty of cutting it without a special tool. Efforts were therefore made to introduce twine instead. But twine cannot be fastened by mere twisting; it has to be tied and a mechanical means of tying a knot was far from an easy problem to solve. While it is true that the human body is a machine and every movement of which it is capable may be reproduced by mechanical means, the difficulty is to copy many operations without involving such complexity of members as to make the mechanism wholly impracticable. The human hand is really a very intricate piece of mechanism which by long generations of evolution and development has become wonderfully deft. It exhibits this deftness and complexity of movement in tying knots and the very intricacy of this operation was enough to baffle the majority of inventors. There was one inventor, however, who was not to be thwarted even by so formidable an obstacle as this. In 1864 Jacob Behel secured a patent on an attachment for binders which would actually tie a knot. The mechanism passed the twine around the gavel of grain, formed a loop in the two ends, and tied a simple overhand knot in much the same way that the hand ties this knot. Ten years later Marquis L. Gorham improved the mechanism and built a successful twine binder. Finally in 1879 John F. Appleby perfected the binding mechanism, completing the last stage in the development of the modern automatic self-binding reaper.