A machine exhibited at the World's Fair in London, by C. H. McCormick, had the "straight sickle blade," but alternating the cuts every few inches. With such a machine it is impracticable to cut grain, much less grass, efficiently, divested of the reel. That plan has since been changed to a much more efficient blade, the scolloped edged sickle. That it was used in the Northwestern States by others several years previous to its adoption by C. H. McCormick, we believe admits of just as little doubt, as rests with the priority of invention of the Reel, Rakers-seat, etc. There is one other important feature, patented in 1845 and referred to in the Pusey letter;--an "Iron case to preserve the sickles from clogging;" these we will also take a look into after a while. Obed Hussey, as appears by the evidence before us, made his first machine in Cincinnati, Ohio, where he then resided, in the spring of 1833, and it was patented the same year. [Sidenote: The Hussey Principle] His principle--the arrangement and construction of the Guards and Knives--was precisely identical with those used by him at the present day, except an improvement patented in 1847, leaving openings at the back end of the slot in the guards for the escape of particles of straw or grass that might get in between the blades and guards. It was communicated at the time by letter with a diagram to a personal friend now living, and of the highest respectability, from whom we have a certificate, and copy of the drawing. The knives or cutters, for lack of more suitable materials were made out of hand saw blades cut into suitable form, and riveted to a bar, vibrating through an opening or slot in the guards. [Sidenote: An Early Experiment] Judge Foster, residing within a few miles of the city, and to whom he applied, kindly offered him every facility to test the machine by cutting grain, ripe and unripe, being himself greatly interested in its success. When taken to the field, a considerable number of persons were attracted to the spot; and rather to the discomfiture of the inventor, for it may well be supposed it was an anxious moment to him, and he desired _no witnesses to his failure_. The machine was started; but owing to some part giving away, or some slight defect not apparent until then, it failed to work satisfactorily. One burley fellow present picked up a cradle, and, swinging it with an air of great exultation, exclaimed, "this is the machine to cut the wheat!" After the jeers and merriment of the crowd had somewhat subsided, the inventor remedied the defect, and assisted by the laborers present--the horses having been removed--pulled the machine to the top of an adjacent hill; when alone, he drew the machine down the hill, and through the standing grain, when it cut every head clean in its track!