This, however, does not prove that the law of which we have been speaking does not exist, but only that there is some antagonizing principle at work, capable for a time of making head against the law. Such an agency there is, in habitual antagonism to the law of diminishing return from land; and to the consideration of this we shall now proceed. It is no other than the progress of civilization. The most obvious [part of it] is the progress of agricultural knowledge, skill, and invention. Improved processes of agriculture are of two kinds: (1) some enable the land to yield a greater absolute produce, without an equivalent increase of labor; (2) others have not the power of increasing the produce, but have that of diminishing the labor and expense by which it is obtained. (1.) Among the first are to be reckoned the disuse of fallows, by means of the rotation of crops; and the introduction of new articles of cultivation capable of entering advantageously into the rotation. The change made in agriculture toward the close of the last century, by the introduction of turnip-husbandry, is spoken of as amounting to a revolution. Next in order comes the introduction of new articles of food, containing a greater amount of sustenance, like the potato, or more productive species or varieties of the same plant, such as the Swedish turnip. In the same class of improvements must be placed a better knowledge of the properties of manures, and of the most effectual modes of applying them; the introduction of new and more powerful fertilizing agents, such as guano, and the conversion to the same purpose of substances previously wasted; inventions like subsoil-plowing or tile-draining, by which the produce of some kinds of lands is so greatly multiplied; improvements in the breed or feeding of laboring cattle; augmented stock, of the animals which consume and convert into human food what would otherwise be wasted; and the like. (2.) The other sort of improvements, those which diminish labor, but without increasing the capacity of the land to produce, are such as the improved construction of tools; the introduction of new instruments which spare manual labor, as the winnowing and thrashing machines. These improvements do not add to the productiveness of the land, but they are equally calculated with the former to counteract the tendency in the cost of production of agricultural produce, to rise with the progress of population and demand. § 3. —In Railways. Analogous in effect to this second class of agricultural improvements are improved means of communication. Good roads are equivalent to good tools. It is of no consequence whether the economy of labor takes place in extracting the produce from the soil, or in conveying it to the place where it is to be consumed.