One of his first trials was with the African, of which he applied 400 lbs. to the acre upon 27 acres, which would not produce three bushels of wheat to the acre, in its natural condition, but with this application, notwithstanding it was 32 per cent. water, and, consequently, had lost much of it ammonia, he made an average of 12-3/4 bushels to the acre on the whole field. Upon another, he increased the usual average yield from 8 to 18 bushels, while, in his opinion, the permanent improvement of the land was of greater value than the increased yield of the first crop; for now clover will grow where none would grow before; another advantage arising from guano is, the wheat ripens so much earlier (15th of June) it escapes the rust, so apt to blight that which is late coming to maturity. He now sows wheat in the fore part of September, three pecks to the acre, after having previously plowed in 200 lbs. of Peruvian guano to the acre, and after the first harrowing sows the clover seed. The land is a yellow clay loam, uneven surface, very much worn; in fact, without the guano, and with all the manure that could be made upon the farm--for no straw no manure--not worth cultivating. Dr. F. had been using guano three years, at the date of our visit, and thought his prospect good for a thousand bushels of wheat upon the same ground, which, without guano would not produce one hundred and fifty. MR. NEWTON'S EXPERIMENTS. The Hon. Willoughby Newton, of Westmoreland County, was one of the earliest and most successful experimenters in the use of guano in Virginia. He owns large and productive farms on the Potomac, but on account of the forest land being more healthy for a residence, he bought a tract of it for that purpose; not having any design of ever putting it into cultivation. In fact, it was so poor he could not. The manure of the farm, if it had not been wanted there, was several miles distant--too far to haul; and so the land lay an uncultivated, unprofitable barren waste around his fine mansion; but it did not lay so very long after he discovered the renovating power of guano. It is now annually covered with broad fields of wheat, from which he has realized upwards of twenty bushels to the acre; and the most luxuriant growths of clover upon which he can pasture any amount of stock he pleases, where three years previous a goat would have found difficulty in sustaining life. Mr. Newton's first experiment--what was then an experiment is now a certainty--was made with African guano. But we will give the account of his operations in his own straight-forward, easily understood, farmer-like language.