THE CULTURE OF FAKM CHOPS. 



CHAPTER XXXIII. 



MANUFACTURED MANURES. 



The necessity for the production of the largest possible 

 crops to meet the exacting competition of the very exten- 

 sive and fertile grain producing regions of the North-west, 

 opened by the trans-continental railroads; together with the 

 general depression of prices of agricultural products during 

 several years past, has led to the introduction and use of a 

 variety of manufactured manures; commonly called artifi- 

 cial fertilizers. These consist chiefly of Superphosphate of 

 Lime, made from bones, either raw or which have been 

 boiled to extract the glue from them, or from the various 

 mineral phosphates; the so called Special Fertilizers or com- 

 plete manures, prepared for particular crops ; Sulphate of Am- 

 monia, a waste product of the gas manufacture; Fish Scrap 

 or Fish Guano, a refuse of the fish oil factories ; Dried Blood 

 and Flesh; Ground Bone; Wool Waste; Castor Oil Pom- 

 ace; Leather Waste; Soot; Cotton Seed Cake, and other 

 oil cakes; all of which furnish a very large amount of most 

 valuable plant foqd for crops, and which form the basis of a 

 trade at present amounting to many million dollars, and 

 rapidly extending and increasing in value and importance 

 to the farmers. The most important of these is 

 SUPERPHOSPHATE OF LIME. 



This fertilizer consists of phosphate of lime in the form of 

 bones; or the mineral apatite; or the organic remains of 

 prehistoric animals which are found buried in vast quanti- 

 ties near the sea coast of North and South Carolina, and 

 known as Charleston phosphates; which are treated by sul- 

 phuric acid. This acid decomposes the phosphate of lime, 

 and unites with a portion of lime, leaving the phosphoric 

 acid in a separated and soluble condition. The discovery 

 of this process is due to the eminent German chemist Liebig, 

 who was led to it by a series of investigations in regard to 



