The department of Agricultural Machinery and Implements was decidedly the most interesting of any. No other can at all equal it in the rapidity and universality of progress from year to year. Of Plows, there cannot have been less than two hundred on the ground, exhibiting a great variety of novel excellence. One with two shares, contrived to cut two furrows at once, seemed the most useful of any recently invented. The upper share cuts and turns the sward to the depth of five inches, which is immediately buried seven inches deep by the earth turned up by the deeper share. Since it is impossible to induce one farmer in twenty to subsoil, this, as the next best thing, ought to be universally adopted. Seed-Sowers, Corn-Planters, Reapers, Fanning-Mills, Straw-Cutters, &c., &c., were abundant, and evinced many improvements on the best of former years. A Mower with which a man, boy, and span of horses, will cut and spread ten acres per day of grass, however heavy, on tolerably level land--both cutting and spreading better than the hand-impelled scythe and stick will do--was among the new inventions; also two threshers and cleaners, each of them warranted to thresh and nearly clean, by the labor of four men, a boy, and two horses, over one hundred bushels of wheat or two hundred bushels of oats per day. The testimony of candid citizens who had used them, and the evidence of our own senses, left no doubt on our mind of the correctness of these assertions. But we do not write to commend any article, but to call attention to the great and cheering truth which underlies them all. Agriculture is a noble art, involving the knowledge of almost all the practical sciences--chemistry, geology, climatology, mechanics, &c. It is not merely progressive, but rapidly progressing, so that fifty days' labor on the same soil produce far more grain or hay now than they did half a century ago. And every year is increasing and rendering more palpable the pressing need of a PRACTICAL COLLEGE, wherein Agriculture, Mechanics, and the sciences auxiliary thereto shall be ably and thoroughly taught to thousands and tens of thousands of our countrymen, who shall in turn become the disseminators of the truths thus inculcated to the youth of every county and township in the country. And thus shall Agriculture be rendered what it should be--not only the most essential but the most intellectual and attractive among the industrial avocations of mankind. HORACE GREELEY [Illustration: THE VIRGINIA REAPER. _Exhibited at the Crystal Palace, and the New-York State Agricultural Fair, by Cyrus H. McCormick_.] WILLIAM ROSS WALLACE. [Illustration]