_Law of diminishing returns._—In considering the value of farm products, it is necessary to notice a natural tendency in all products of the earth toward greater cost of effort in production. This is called the law of diminishing returns, and is illustrated in every industry where the accumulations of nature are depended upon for making labor effective. Hunting, fishing and mining afford familiar illustrations of more work of the same kind for equal product. Agriculture, however, gives the most extensive available illustration of the facts grouped under this law. In the first place, the farmer is subject to it by mere location. The product of a field near his house and barn costs less exertion than the product of a more distant field. In the second place, he is likely to have chosen for his first efforts in crop raising the land most readily yielding its fertility in crops. If he extends his operations to less productive soil, he must work more for the same product. In the third place, if a certain amount of work upon a certain field will give him twenty bushels of wheat, he must give a good deal more than twice as much work in the way of tillage and manufactured fertilizer to make a crop of forty bushels. The proof of this is clear in the disposition of farmers to buy more land instead of to increase labor upon a limited space possessed. A specific statement of the law of diminishing returns is that _in the cultivation of land an increased amount of effort under usual conditions fails to give a correspondingly increased amount of produce_. _Exceptions to law of diminishing returns._—Exceptions to this law are easy to find, as where the first selection of land in a new country has had reference rather to safety from wild beasts and savages or malarial diseases than actual store of fertility. Another exception is found in any new country, where imperfect adjustment of labor to conditions of soil and climate are liable at the outset to prevent the full use of natural powers of the soil. So evident are these two exceptions in imperfectly developed agriculture that some have disputed the general fact, yet all must admit the certainty of diminished returns from multiplication of the same kind of efforts upon the same space, and general proof is abundant in all long settled communities.