The impossibility of procuring bones enough to supply the wants of the comparative few now engaged in using guano, may be readily learned by any farmer who uses ten tons of guano per annum, if he will undertake to "pick up bones" enough to furnish him the same amount of phosphates contained in that quantity of guano. Then if all who are now using it, would drop guano and take to bones, it would soon be found to be hard picking. Save all the bones and apply them to the soil, is a standing text with us; upon the same soil use all the guano your can procure and you will not need to pick bones--you will grow bones to pick. It may be very patriotic to talk about expending the money at home, for bones, instead of sending it to Peru, for guano; but that talk is all for Buncombe, there is not a particle of sound reason in it. If all the bones in the United States could be saved and applied to the land again, we should still fall short of a supply, and be obliged to do as England did before the introduction of guano; go about and ransack grave yards of great battlefields, for more bones. With all the guano imported, or that will be imported, and all the bones that will be saved, there will still be room for more phosphates in the millions of acres of hungry soil in America. What would be the effect if a few such farms as Willoughby Newton's, and Col. Carter's, who each use 30 to 40 tons per annum of guano, should come all at once into the bone market for their supplies. In our opinion there would be such a rattling among the dry bones, we should hear no more about substituting them for guano. The fact is an incontrovertible one, that nothing on earth nor under the earth, or in the sea, has ever been discovered, which can be used as a substitute for guano. Its small bulk is alone sufficient to commend it to favor. The Royal Agricultural Society of England offers a prize of L1,000 and the gold medal of the society, for the discovery of a manure with equal fertilizing properties to the guano, of which an unlimited supply can be furnished in England, at L5 per ton. "_Analogy between Bones and Guano._--There is a striking analogy in composition between bones and guano, which is, for other reasons interesting to the practical man. The following table exhibits the composition of bones compared with guano, supposing both in the dry state. Bones, as they are applied to to the land contain about 18 per cent. of water. Ichaboe guano from 20 to 25 per cent. _Bones._ _Guano._ Organic animal matter, 33 56 Phosphates of lime and magnesia, 59 26 Carbonate of lime, 4 6 Salts of soda, 4 10 Salts of potash, trace trace Silicious matter 0 2 ---- ---- 100 100"