Nitrogen and potash are about the best elements in artificial fertilizers and perhaps the hardest to retain. We have learned that nitrogen can be best and cheapest added to the soil by means of certain cover crops, or crops sown only to be turned back into the ground as green manure. It is also present in large quantities in stable manure, if it has not leached away before being put on the field. But this book could scarcely tell you all about the best ways of handling manure to get the best returns. The Government, however, has done this, in Bulletin 192, and you cannot do better than send for it and study it carefully. You will learn from it the immense importance of taking proper care of the manure you have, and how to get the best possible results from its use. Also, what sorts of manure are best for what special purposes. If the manure is carefully handled, that which is obtained from stock fed for soiling purposes—that is, especially to provide manure—is the best. It contains almost all the elements that the growing crops took from the soil. One well-fed dairy cow will produce 12¾ tons of manure in one year, says Prof. E. B. Vorhees, and this manure will contain about 117 pounds of nitrogen, 77 pounds of phosphoric acid, and 89 pounds of potash. This much stable manure, if all the constituents are saved by housing and careful handling, will grow about 70 bushels of wheat and the accompanying straw. As all this nitrogen, phosphoric acid and potash have been drawn from the soil first in the crops fed to the cow, the only way to keep up the fertility of the soil is to return them to it. In the form of commercial fertilizers these would cost more than $30, or 20 cents per pound for nitrogen and 4½ cents per pound for potash and phosphoric acid. So if you keep one cow and feed her well, she will return to you almost her value in manure each year, to say nothing of the milk and butter your family can have. The family horse, as well as the cow, will give you valuable returns in manure, if you know enough or care enough, to preserve it properly. When immediate spreading on the fields is not possible, the manure, both liquid and solid, should be kept in a tight pit, or under cover. If too much litter has not been used, the liquid part will prevent loss from too rapid fermentation. But if there is litter enough to make the manure very dry, some water should be added from time to time to let fermentation go on without loss. Manure thus cared for will be ready for use on the land at any time that it is needed, and will contain practically all the necessary fertilizing properties.