Of all the arts of life, there is none which draws its knowledge from so great a variety of fountains as practical agriculture. Every branch of human knowledge is mutually connected--we may say interwoven with--and throws light upon, or is enlightened by, every other. But none of those which largely contribute to the maintenance of social life, and conduce to the power and stability of states, is so varied in its demands upon the results of intellectual inquiry, as husbandry,--or rural economy in its largest sense. Look at that magnificent ship, which cleaves the waters, now trusting to her canvass and wafted by favouring breezes; now, despite the fiercest gales, paddling her triumphant way over hill and valley, precipice and ravine, which the raging sea, out of her fertile materials, is every moment fashioning beneath her feet. Is there any product of human art in which more intellect is embodied than in this piece of living mechanism? The timber can tell of the axe of the woodman on far-distant hills, and of the toils of many craftsmen in fitting it for its present purpose. The iron of the researches of the mineralogist, the laborious skill of the miner, the alchemy of the smelter, the wonders of the tilt-hammer, the ingenuity of the mechanist, and the almost inconceivable and mathematical nicety by which its various portions are fitted to each other, and, like the muscles and sinews of the human body, made to play together for a purpose previously contemplated--an uninstructed man might almost say, previously agreed upon among themselves. The steam, of what hidden secrets of nature!--the mysteries of heat, which could not hide themselves from the searching genius of Black,--the chemistry of water, which the ever-pondering mind of Watt compelled from unwilling nature,--the endless contrivances by which its fierce power was tamed to most submissive obedience in the workshops of Soho. The compass may for a moment carry us back to the fabled mountains of our infancy, in which the hidden loadstone attracted the fated vessel to its ruin; but it brings us forward again to the truer marvels of modern magnetism, and to the intellect which has been expended in keeping the needle true to the pole-star in the iron boat, where, surrounded by metallic influences, countless attractions are incessantly soliciting it to deviate. And when, as the mid-day sun mounts to the zenith, the sextant and the quicksilver appear, how does it flash upon us that modern navigation is the child of astronomy; and that the mind embodied in the latest Rossian telescope is part and parcel of the inappreciable mass of thought to which, "walking the waters as a thing of life," that huge steam-frigate owes its being!