In no other part of the world, perhaps, can the beneficial effects of Guano be more plainly seen than in the tide-water region of Virginia. In the counties of King George, Westmoreland, Richmond, Northumberland, Lancaster, in the northern neck, as the peninsula between the Potomac and Rappahanock is termed; thousands of acres of land so poor and worthless a few years ago, it was barely rated as property, are now annually producing beautiful crops of wheat, corn and clover, solely by the application of Guano. In the meantime, the discovery of such an easy means of improving a worn out and barren soil, has increased the money value of land three or four hundred per cent. This is not all. Heretofore, the only part of this district considered worth cultivation was the bottom land bordering the rivers and creeks; the forest land yielding scanty crops for two or three years after being cleared, scarcely paying for the labor, while its value was rated at from $1 to $4 per acre, and unsaleable at that. Since the introduction of Guano, it is found these forest lands, which are of a sandy, loamy character, and much more pleasant than the bottom lands to till, can be cultivated with equal or greater profit than the stiff lands upon the bottoms. The writer has seen repeatedly in the counties mentioned, luxuriant fields of wheat, corn and clover, while directly alongside of such crops, the ground was almost as bare of vegetation as the sea-shore sands, too poor, as the common expression is there, to bear poverty grass. And what produced this change? Simply a dressing of 200 lbs. of Guano to the acre. DR. FAIRFAX'S EXPERIMENTS WITH GUANO. In April 1850 the writer was on the farm of Dr. Fairfax of King George county, who was one of the first, if not quite the first person in that part of the State who ever made use of this substance as a manure; and his wheat was then so large that a good sized dog was hidden from view in running through the field; while upon a neighboring piece of land of exactly the same quality, sowed at the same time, the ground scarcely looked green; in fact, it was remarked at the time by way of contrast to the one field hiding a dog, that the other would not hide a chicken--indeed, an egg might have been seen as far as though no wheat was growing upon the ground. Both fields were just alike, both plowed and sowed alike, without manure, except 200 lbs of Peruvian guano upon one, and that sure to bring fifteen or twenty bushels to the acre, while the other would not exceed three bushels.