350' Chemical Composition and Commercial Value of 
XVIII. — On the Chemical Composition and Commercial Value of 
Norwegian Apatite, Spanish Phosphorite, Coj>rolites, and other 
Phospliatic Materials used in England for Agricultural Purposes. 
By Dr. Augustus Voelckeu. 
When superphosphate of lime Avas 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 em- 
ployed 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 con- 
siderable 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 
othf-r kinds of fertilizers have been tried on a large scale, 
