_Value of Guano on account of its Phosphates._--He who wishes to have the best grazing grounds, where he can present the richest and most nutritious herbage to his cattle, will keep his ground well supplied or manured with guano that abounds in phosphates, knowing that it will supply the needed nutriment to the grass, and by the grass to the cattle; and thus his stock will be kept in a high condition and full flesh, either for the farm or the market. Again; he who raises wheat, corn, or other grains, has an equal inducement to look to it that his manures are abundantly impregnated with these essential elements. Phosphates, so available to the raiser of stock, are equally so to the producer of grain; because the size, richness, and nutritious qualities of the grain depend largely on the presence of these in the soil. A farmer, therefore, has a vital interest in this matter, and should obtain what best suits his purpose. The most intelligent English farmers are so well convinced on this point, that substances containing only ten per cent. of phosphate of lime, are sought after, dissolved in sulphuric acid and water, and sprinkled on the soil. Bone dust also is used, and to a certain extent, is available, because one of the principal constituents of bones, is phosphate of lime. But the article in which the phosphates are the most convenient, because the most minutely distributed, is guano; and this, when judiciously used, must find favor wherever it can be obtained. That which contains a large proportion of phosphates, in combination with ammonia, nitrogen and alkaline salts, apparently in the exact proportion required by nature, such as analysis and experience proves is the case with Peruvian guano, will be sought after by every farmer who reads the evidence of its value which we have given in these pages. It is idle to talk of bones to restore the waste of phosphates in the soil that is being constantly carried away in grass and grain, beef, pork, mutton, milk and cheese, much of which passes into the sea from the sewers of cities, to be there retained in that great reservoir for the future use of men. It is from that we are now drawing our present supplies. Happily for mankind in all civilized countries, the discovery of guano has, in a providential manner, met the very wants of the times, in reference to the reinvigoration of certain kinds of soil, since this manure furnishes the elements most needed to supply the waste arising from cultivation, and to develop vegetation.