It will soon be a great object with American farmers to cultivate locust-trees, in all locations to which they are adapted. Even in this new world, we shall soon be dependent on cultivated timber for fence-posts, railroad-ties, and building purposes. Our native forests are rapidly disappearing, while demand for timber is as rapidly increasing. Probably no other tree is so profitable for cultivation in this country as the locust. It is of rapid growth, and hard and durable, and adapted to many uses. The second-growth locust is not so durable as the native forest-tree, as found in parts of Ohio; but, cut at a suitable age and at the right season of the year, it is as durable as white cedar, and much more valuable. The profits of the culture would be great. An acre of locust-trees fifteen or twenty years old would be worth fifteen hundred or two thousand dollars. The expense of growing it, aside from the use of the land, would be trifling. The grove would afford a good place for fowls, while the blossoms would be nearly equal to white clover for honey. The limbs would make excellent wood, and the ground would need no planting for a second growth. Fortunate will be the men on the prairies of the West, and along the railroads and rivers of the land, who shall early plant fields of locust. The profits of it will greatly exceed the increase in the value of the land. MANURES. Soils, manures, and preparing the soil--plowing, harrowing, &c.--are the three great subjects in any good agricultural work. We shall treat this subject under the following divisions:-- 1. The substances of which manures are composed. 2. Preparation and saving of manures. 3. Time and modes of application. 4. The principles of their action upon plants.