CHEMICAL COMPOSITION AND COMMEKCIAL 

 VALUE OF PHOSPHATIC MANURES. 



WHEN superphosphate of lime was first introduced into agri- 

 culture, it was exclusively prepared from raw or boiled bones. 

 It was then sold more frequently under the name of dissolved 

 bones and of German compost than under that of superphosphate. 

 Animal black or bone-charcoal, in the shape of refuse from 

 sugar-refineries, and South-American bone-ash, were soon recog- 

 nised as valuable materials for the production of artificial 

 manures. In some respects these refuse matters were found even 

 superior to bones for making superphosphate. They are now 

 eagerly bought up by manure-merchants, and extensively employed 

 in the manufacture of phosphatic and other artificial manures. 



The timely discovery of fossil bones and phosphatic nodules 

 in the Suffolk crag, and of chalk coprolites further provided an 

 abundant source of phosphates in our own country, to meet the 

 yearly increasing demand for those artificials which owe their 

 efficacy principally to the valuable phosphate of lime which 

 they contain. But raw and boiled bones, animal black, South- 

 American bone-ash, Suffolk and Cambridgeshire coprolites, are 

 not the only materials that are employed at the present time in 

 the manufacture of superphosphate. Apatite from Norway, 

 phosphorite from Estramadura, Sombrero phosphate or Crust 

 guano, American phosphates of various kinds, and certain 

 phosphatic guanos, are likewise imported into England in consi- 

 derable quantities, and converted, by means of sulphuric acid, into 

 valuable manures, to the mutual benefit of producer and consumer. 



Manure manufactories are now spread over the length and 

 breadth of the country, and in all these works the staple product, 

 under whatsoever name it may be sent out, is in reality, in nine 

 cases out of ten, superphosphate of lime. The consumption of 

 this kind of manure, large as it is at present, is increasing every 

 year, and is likely to increase for years to come. It must not be 

 supposed that the large demand for phosphatic manures is the 

 result of extraordinary exertions on the part of the manure-mer- 

 chants, or is due to a prevailing, and it may be passing, faith in 

 this class of fertilizers. It rests on the universal experience of 

 farmers that no description of manure repays a judicious outlay 

 so well as this, especially when applied to root-crops. Whilst 

 other kinds of fertilizers have been tried on a large scale, 



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