538 AGRICULTURE. 



sustained, and mainly brought about, by the public analysts, 

 and the laws passed at their instance. 



The chief ammoniating materials, used in the manufacture of 

 ammoniated superphosphates, are various nitrogenized organic 

 matters, mainly of animal origin ; sulphate of ammonia, and 

 nitrate of soda ; rarely, nitrate of potash is used. The phos- 

 phates used in making this class of goods are exclusively of 

 mineral origin. Animal bone costs more than double as much 

 as mineral phosphate, and no manufacturer using bone could 

 compete in this trade. The term " bone phosphate of lime," 

 often used in the report of the analysis, has led many to sup- 

 pose that bone is the source of the phosphate ; but " so much 

 phosphoric acid equivalent to so much bone phosphate of lime" 

 means only that that quantity of acid would combine with three 

 equivalents of lime to form that quantity of tribasic phosphate, 

 which is the form existing in bone. The statement is of no 

 possible value, for the phosphoric acid referred to is the aggre- 

 gate of soluble, insoluble, and so-called " reverted," found in the 

 sample. The actual meaning is, that this quantity of phosphoric 

 acid is chemically capable of forming the stated quantity of 

 " bone " or tricalcic phosphate. 



Among the "ammoniates" of organic origin used in this line 

 of goods, undoubtedly the best is steam-dried blood, known to 

 the trade as red blood ; the fire-dried or black blood is partially 

 charred, and of less value. Fish-scrap, or the refuse of fish-oil 

 factories, is an excellent " ammoniate " ; as is, also, slaughter- 

 house refuse of one sort or another, sold as " Animal Fibre," 

 " Flesh Dust," and by other names. Woollen refuse, hair, hoof 

 and horn shavings, form a secondary class, which analyze well 

 but produce very little effect in the field. Finally, parched and 

 ground leather scrap, which is the refuse of shoe and harness 

 factories, which analyzes remarkably well, is almost entirely 

 worthless, and is unfortunately largely sold and used. 



It is here that the false and misleading results of the work of 

 analysts, as published, produce great mischief. All these am- 

 moniates are indiscriminately reduced to ammonia, by the ana- 

 lytical process, and reported as of identical value, and that value 

 deduced from the cost of such materials as steam-dried blood 

 and sulphate of ammonia. That that which is inferior should be 



